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The Converter’s Guide to the Galaxy and EV

Conversions

By

Richard W. Marks President

EnVironmental Transportation Solutions, LLC

rev. December 15, 2008 Rev. April 24, 2015

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Table of Contents Introduction: .................................................................................................................................... 3 Chapter 1: The Art of Designing a “Real” Vehicle or an EV Conversion Vehicle ........................ 8 Chapter 2: High Voltage Safety and Overall Vehicle Safety/Reliability/Durability ................... 18 Chapter 3: EV Batteries for Conversion Vehicles ........................................................................ 24 Chapter 4: EV Chargers for Conversion Vehicles ........................................................................ 37 Chapter 5: Drive Systems for EV Conversions ............................................................................ 41 Chapter 6: Automotive Electrical Systems for EV Conversions .................................................. 59 Chapter 7: Original ICE vehicle and its systems .......................................................................... 66 Chapter 8: Conversion Process .................................................................................................... 73 Chapter 9: Example of an “OEM-grade” conversion ................................................................... 77 Chapter 10: Conclusions about Conversions .............................................................................. 108 Chapter 11: Bibliography ............................................................................................................ 110 Chapter 12: Appendices .............................................................................................................. 112

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Introduction: Welcome to the Converter’s Guide to the Galaxy and EV Conversions. Why the Galaxy? Well, EV’s or Electric Vehicles work just about any where. We put EV rovers on the Moon and they work great. EV’s do not burn anything! They do not need oxygen to function. Solar energy can easily be converted to electricity and is exactly what powers most satellites in outer space. So when you take your EV into the Galaxy, you are ready to rock and roll on the highways in the Galaxy. But putting aside this meager bit of humor, I want to get serious about electric vehicles and in particular their high voltage safety and the use of proper design elements in building a conversion vehicle. This book is not a how to do guide although Chapter 9 speaks to converting a vehicle as an example of how the principles are applied to a create a “road-worthy” conversion vehicle. The Guide provides insight that is not readily available for electric vehicle converters today. The author’s experience in the automobile industry is extensive and he brings that knowledge to help converters understand the reasons for doing things “OEM automotive-like” and the potential consequences for not doing items that way. The choice is yours on how to build your EV Conversion; this book gives insight into how to do your conversion with proper focus on safety from many different perspectives. I recommend that you read this book carefully with an open mind; the only difference in doing it better is knowledge that you can gain here and a few extra steps and pennies. I have read many preambles from suppliers about their parts/services and the need to be careful. I am going to paraphrase what is stated very well in CafeElectric’s Owner’s Manual. Please read this.

WARNING! READ THIS PAGE TO SAVE LIVES

This book is only intended to provide basic guidance for elements of doing an electric vehicle conversion and should be used by qualified and experienced installers/builders. Electric Vehicles use Fatal Voltages (120 to 300+ volts). Do not attempt to work on them unless you are trained in safe design and working practices specific to Electric Vehicles. A vehicle using the various components described in this book can be capable of killing people!

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This can occur both from high voltage shocks and due to many other methods including driver error and unintended acceleration. It is the responsibility of the vehicle designer, installer and builder to insure a safe work-process and finished product. The fine print: Very Important!! The author of this Converter’s Guide to the Galaxy has no control of third party procedures used in the selection and installation of the components mentioned in this book or the modifications that may be made to a vehicle based on guidance provided. The author assumes no liability for vehicle functionality or safety after third party installation of the EV conversion parts either recommended or not recommended or advice given. It is the responsibility of the vehicle designer and component installer to test and qualify their application and to insure proper safety and functionality. The author assumes no responsibility for the applicability of these guidance principles and recommendations in any use. Futhermore: The recommendations and guidance given are intended for use in experimental vehicles and can be very dangerous if not operated properly and responsibly, therefore the reader/modifier/operator assumes all liabilities and risks associated therewith. With the purchase of this book the reader/modifier/operator assumes all risks and acknowledges acceptance of said risk with the purchase and use of this book to modify, convert and operate electric drive vehicles. Additionally, with regard to design or other recommendations and/or product recommendations, the reader/modifier/operator is solely responsible for determining their applicability and suitability for use, for the purpose intended by the reader/modifier/operator. The purchaser(s) of this book agree(s) that they will insure that the purchased products and methods used to convert an existing vehicle will only be used in a safe and lawful manner consistent with the laws, rules, and regulations of the geographic area of the product operation and will assume all risks and liabilities associated therewith and will hold the author, its agents, employees, officers, suppliers, publisher, and vendors harmless. Please note that is not to indicate that EV’s are unsafe or dangerous. If done properly EV’s are very safe. The purpose of this introduction is give this simple advise: Be careful and respectful of high voltage, it can kill you. Enjoy this guide and please update me with your experiences and suggestions to improve this book. Technology changes daily in our lives and

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it will not take long before there are better ways to do things than what is indicated here. But most important is to enjoy your experience converting your gas car/truck to electric drive...it is the future and the future starts today. That you can count on! Respectively submitted, Richard W. Marks President EnVironmental Transportation Solutions, LLC Detroit, MI www.EcoVElectric.com RWMarks@EcoVElectric.com Biographical background on author: The author has always been interested in mechanical and electrical things. From early ages he took things apart and put them back together. He took that interest to college and graduated from University of Maryland with a BSME (Mechanical Engineering). He then went on to Cornell University and graduated with a MSME. He was recruited by General Motors Research Labs and went to work with GM in Warren, MI. He decided early on he wanted to get the experiences necessary to become a Car Division Chief Engineer. While that never happened, he did get a variety of great experiences in areas of vehicle structure, safety, durability, ride pleasibility, weight control, international structures program coordination, aero dynamics, chassis systems, and electric vehicles. He spent 25 years with GM, but his last 5 years were involved the EV1 electric vehicle program and with EV conversion programs. He worked on the vehicle systems and assembly side and was involved with all the engineers and management team on the entire vehicle. He then initiated an activity to develop EV conversions that GM and its manufacturing partners could build in their own plants. While the EV1 was exceptional, it was also very expensive to develop and build. Conversions offered GM an opportunity to market and sell a much lower price EV to the commercial and consumer markets. He and his team built the first Chevy S10 conversion for GM and GM took that to production, but not with the author involved or in the way he had originally intended. The S10 GM built was costly and did not do very well in the market for many reasons. After the S10, he pursued a relationship with Toyota to build a Geo Prizm conversion in the Fremont, CA plant. That project got relatively far along,

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until GM and Toyota could not resolve financial issues. Then his team converted a Geo Tracker 4 door to electric drive for a management demonstration and it was accepted as a worthwhile project to continue. The team pursued a relationship with Suzuki to convert the Tracker in the CAMI plant in Canada. Suzuki got very involved in the project and wanted to do this. Between the Toyota and Suzuki projects, the author made many trips to Japan and Europe and met with many of the suppliers making EV parts. Tracker was coming in initially too expensive and the team was told to reduce the cost by 30% if it was ever to reach production. Six months later the team had reduced costs more than 30% but GM decided they had changed their minds. The author then went off and pursued a couple other conversions. One was going to be a low cost Postal Truck conversion (never built), well before the USPS issued their RFP for one in the 1998 time-frame. The other was to convert a small car, the “Chevy,” being built for the Mexican market (Actually it was a German Opel small car produced in Mexico). This project was coordinated and guided with two outside suppliers who had a great deal of electric vehicle experience. Two cars were converted. The one selected was outstanding and demonstrated how simple and low-cost a small car conversion could be. The car did not have air conditioning, but did have everything else. It went 65 mph and about 50-60 miles on a charge. It could be assembled in Mexico on the assembly line and brought to the US and certified. But again GM got cold feet and it was at that point that the author decided that his commitment to EV’s was far greater than GM’s. He left GM and walked out the door after nearly 25 years. The over the next 6 years, the author took on two jobs with a couple of Tier 1 suppliers to the major US OEM’s. He got great experiences to complement his GM experiences. He learned how to quote projects, work with Tier 2 & 3 suppliers, did supplier development, learned quality systems, did Process Sign-Offs and Production Part Approval Processes, worked with manufacturing sites and even set up a low volume assembly line to build a specialty automotive truck. All of this was done as he continued to be in charge of the Engineering & Design Teams, and responsible for Project Management and Profit/Loss. Both jobs ended when both companies re-organized under new management from outside of the US. At that point the author came back to his passion for electric vehicles and started a consulting company on EV’s, EnVironmental Transportation Solutions, LLC. He consulted for two companies trying to develop neighborhood and highway electric vehicles. Both companies failed to find investors and pay him for his work so finally he left to do his own road-worthy electric Low Speed Vehicle. He brought his work back to Michigan

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which included several prototypes he, with the help of others, had built (at his expense.) The EcoVElectric is the product his company is working on to get funded. Hopefully, if there are any proceeds from this book, they will go to help EcoV become a reality. So thank you for buying the Guide! It should help the EV cause in many different ways. Lastly, in 2007 he joined the Electric Automobile Association (www.EAAEV.org) and got involved in creating a new Michigan Chapter. His goal was to help the EV converters of the EAA to understand better how to improve their conversions in many different regards. His focus has been on safety and reliability. This Guide is a result of that desire. Join EAA; it is a great organization and they will help you with your conversion, too. UPDATE: A lot has happened since I started this book. In 2008 there were only rumors of up and coming electric vehicles and plug-in hybrid electric vehicles. Today, in 2015, there are more and more choices for people interested in EV’s. Unfortunately most are very expensive but to reduce the price there are number of incentives or tax credits, both at Federal and State levels. While I don’t particularly support tax breaks for the wealthy, they do exist and if you make enough money or lease an EV you will benefit. The interest in doing EV Conversions has lessened since a good EV conversion can still cost a lot of money and hardly competes with today’s EV’s and all their fancy electronics. One should note that EV’s are being greatly subsidized by both the Government and more by the automakers. Nobody today is making any money on EV’s, NOBODY. What is missing in today’s World are affordable EV’s for the masses. Be sure to check out my company EcoVElectric.com. Conversions can be an attempt to build an affordable EV and if that is your intent then my book may be of help to you doing it safer. Best of Luck to you!

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Chapter 1: The Art of Designing a “Real” Vehicle or an EV Conversion Vehicle

Congratulations! You have made a conscious decision to learn more about converting old generation, oil-addicted Internal Combustion Engine (ICE) vehicles into next generation clean technology transportation solutions. Electric vehicles are coming and the pressure for the automotive OEM’s (Original Equipment Manufacturer) to build them is growing daily. There is much available to read about EV’s and why they make so much sense. There is controversy as well: are EV’s really good for the environment? But besides that, there is definite certainty that EV’s will reduce our Nation’s dependency on foreign oil, improve the air quality in our cities, and can provide new long lasting jobs in America through the building of EV’s and their associated parts and systems. All it takes is action and desire. You have shown the desire! Now let’s take some action! Electric vehicle technology is a disruptive technology today for the OEM’s and for all the industries supporting ICE technology (Interestingly, 100years ago, EV’s were the mainstream and oil burning gas engines were coming on strong because of cheap oil.) EV’s will change everything we know about cars today and the consumers will love them. They will require a whole new way for the auto industry and support industries to function and operate profitably. EV’s do not have the complexity of ICE’s resulting in less maintenance and repair. There are no gas fill-ups, no oil changes, no emissions controls, no tune ups, no exhaust systems and with some advance technologies, like regenerative braking, there will be significantly less brake service. All these items will affect auto dealership and after market service industry dramatically. For us the consumer, it sounds great and we can’t wait; but there are dark forces in the Galaxy that do not want this to happen and are dragging their feet. We have seen these forces operate particularly over the last 15 years, since 1994 when California proposed a ZEV (zero emission vehicle) standard which would have require 10% of a large OEM sales in California to be ZEV’s. I was at General Motors at that time and joined forces with the GM EV team to develop and produce the GM EV1. In 1993 actually diverted myself away from the EV1 to get involved in conversion vehicles. GM spent nearly a $1,000,000,000 to develop and produce the 1000 EV1’s (This translates to about $1,000,000 a piece for the each EV1 they built and leased and it included all the R&D, tooling, purchase of very limited production parts, manufacturing and sales/marketing).

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Competing with the clean sheet design of the EV-1 were conversion vehicles that were much more likely to be significantly lower cost to the consumer. The GM EV technology people were against conversions at first because they could do so much better theoretically with a clean sheet design; but someone has to pay for all of the newer technology and that person is you, the consumer or GM Corporate as a longer term investment. These were exciting times and the GM technology people were eager to make ground-up EV’s happen. But EV’s are not new and in fact have been around and continue to come around about every 10 years for the last 100 years. But today, the times have really started to change. Oil this week was nearly $140/barrel and the price of gasoline has hit $4.10/gal as a National average and everyone expects gas will continue to rise higher; $4, $5, $6, $8, $10/gal? Climate change and carbon emissions from burning oil are in the forefront of everyone’s mind as well as. Also air quality is a concern in every populated region of the World. So the question is when will I be able to buy an EV? The answer provided in this guide is RIGHT NOW!!!

How hard can a conversion really be?

The task to design a “real” or a production-like product that behaves the same way as contemporary vehicles of today, is complex and not easily understood by those who have never done it by way of working with an automotive OEM at the engineering level. First, let me explain my term “real.” A “real” vehicle is designed to meet specific customer expectations and when produced in quantity delivers on that promise and does so within the budget planned and the time allotted. What does a real vehicle have to do? It is the integration of hundreds of parts working together in the context of a higher basic plan. Things do not happen by accident; they happen because of the plan. Systems integration is one of the least understood terms and is the one task that separates the good, the bad and the ugly from the great. Systems integration is making the whole greater than the sum of the individual parts. How is that possible? Here is a simple case in point. Search the whole galaxy (Earth will do) and find the very best parts you can find from cars all over. Find the best engine, best transmission, best seats, best doors, best chassis, etc. Now assemble them to build the best car in the world. It will not work, because the parts do not even fit together, they were never designed to work together; that is the job of system integration. Second, let’s define what is complex. The customer is complex in terms of how he or she will use the product and what he or she will expect (you as a

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converter are a customer and so are the people you show your car to.) Customer satisfaction is a mult-level list of factors that go into determining how well the product will be received, ultimately sell and return satisfaction over time. There are performance factors, such as ride comfort, handling, quietness, driveability, operating range on a full charge (EV’s remember!), and how well the vehicle handles the daily missions the driver gives it. There are reliability and durability factors like economy of operation, carefree operation, and quality of parts and systems. There are market factors: perceived value (performance/$), styling, size and image. There are safety factors like damageability, safety and security. And lastly there are outside factors like repair costs, insurance cost, company provided service & assistance, and warranty. Overall the task is to balance all these factors and end up with a long-term happy customer. Looking at recent history only supports how difficult the car business is. The auto industry has not seen new competitors coming into the market. There are exceptions in Asia, but even there, these new companies are learning from older companies through partnerships. One area of interest in the US has been alternative fueled vehicles including electric conversions. There have been many new companies started and then collapse as they learn about the complexities. In order to be successful at any thing, there are: 1.) things you know, you know; 2.) things you know you don’t know but can get help to solve those before it is too late and; 3.) (these are the killers) the things you don’t know, you don’t know. If this last group is significant, you will fail or worse, you will kill or injure someone, if not yourself. This Guide will hopefully greatly reduce the #3 items and help you make sound decisions based on knowledge, not just gut feel. If you want to build a hobby car or a toy car, that is one goal, but if you want a serious EV that you or anyone can use and depend on, that is another higher level goal. So what does a real EV need to be able to do and what are the issues that need to be addressed: Range/Performance:

1. Battery life in miles 2. How far at highway speeds 3. How far at city driving speeds 4. 0-60 mph acceleration time 5. 60-0 stopping distance, feet 6. Curb mass, lbs or kg 7. How steep a hill and for how long and at what speed?

Vehicle Energy Efficiency:

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1. Energy consumption at 55 mph, Watt-hours/mile 2. Energy consumption on city driving schedule, Watt-hours/mile 3. Tire rolling resistance coefficient 4. Transmission efficiency 5. Motor efficiency 6. Controller efficiency 7. Charger efficiency 8. Battery charge efficiency, self-discharge characteristics, and storage

life. 9. Brake rotary drag, Nm

10. Aerodynamic drag coefficient 11. Accessory loads, Watts

Packaging

1. Impact speed at which damage starts to occur to drive system parts, mph

2. Front and rear end packaging for crush 3. Crash deceleration pulse, g’s 4. Maintenance and service accessibility 5. Cargo volume, liters or cubic feet 6. Heating and cooling for passengers

Risk and Failure Modes:

1. Handling high voltages 2. Battery failure modes, consequences and prevention (this includes

everything from batteries gassing and exploding, leaking chemicals, thermal issues, battery failures that leave you stranded, to even containment of batteries and high voltage in accidents and roll-overs)

3. Protection of people inside and outside of vehicle in accidents Vehicle Dynamics

1. Steering efforts 2. Steering response 3. Understeer 4. Coarse road noise 5. Vehicle structural bending frequency, Hz

Environmental Issues:

1. Ambient temperatures in which vehicle will be operated 2. Peak low temperature 3. Peak high temperature 4. Road conditions: salty, dusty, humid, dirt roads, rough roads,

potholes, twisty, up and down hills

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5. Typical weather conditions: rain, snow, fog, hot and sunny, mild, cool and cloudy

6. Other issues, like car washes, alignment equipment, tire repair or rotation, and service repair station jacking locations

7. On a broader scale: end to end lifecycle carbon footprint and environmental impact (Meaning the total impact of producing,(planning, designing, and testing) the vehicle; mining, growing, refining, transporting, etc, the raw materials and subcomponents; assembling and transporting finished vehicles; operating (fuel, maintenance, waste products, storage, etc.) and recycling (landfills, materials recovery), etc)

What does my conversion have to do? This is an important question you need to think about carefully. If you plan to build it and drive it on Sundays to EV events, that is one thing. If you plan to use it daily to accomplish a specific set of missions, that is something else. If you plan to use it to promote a business of converting cars, that is great but also more complex because you have to do it right and safe so nobody gets hurt regardless how stupid they might be and what dumb things they might try. The only thing that all EV conversions must be is SAFE. There are no excuses for not taking the time, effort, and expense to insure no one will get hurt with your EV conversion. This is not an absolute black or white, but rather various shades of grey or understanding the risks and consequences with each decision you make. This guide will tell you how a reasonable high quality conversion on a limited budget should be done as if it were done by someone who understands the issues an OEM would consider. Why mention OEM’s? Well think about the complexities of modern automobiles and how reliable today’s cars are and how long they last. This is not by accident. In a conversion we are using maybe 75% of the original car that the OEM built (frame, suspension, brakes, steering, body, accessories, handling, ride, crash worthiness, etc.). This saves you time, money, and aggravation. This is important and this is why you don’t want to screw up what the OEM’s have spent millions of dollars validating and testing. Where Do I Start? The first question is how much do you want to spend converting an existing vehicle? This answer will change as you learn more about your options. The second question is how far do you want it to go on a charge? This is based on how fast (top speed) do you want your EV to go and how fast do

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you want it to accelerate? You will need to decide what will be your typical driving cycle (speed, distance and terrain.) Answering these questions starts to frame your choices. Limits to consider:

1.) Vehicle rated Gross Vehicle Weight, Front Axle GVW and Rear Axle GVW. (Grosse Vehicle Weight Rating is base vehicle, all fluids, all options, all passengers @ 68kg (150 lbs) each and all rated luggage capacity) These are important because they are the limits that OEM use to design, test and validate the safety, durability, reliability and integrity of their vehicles and in particular their chassis and drivetrains. For crashworthiness, the problem gets sticky since testing is done at maximum curb weight plus driver and passenger. EV conversions can approach GVW, but special care is needed relative to crashworthiness, since the battery weight is part of curb weight. (Curb weight is base vehicle with options and all fluids) GVW numbers are usually posted on a sticker in the front door opening.

2.) Weight of conversion vehicle as received and its front and rear axle

weights. Note what is missing, like full fuel or various missing parts.

3.) Weight of vehicle’s Internal Combustion Engine (ICE) parts 4.) Weight of the EV parts that will be added back in to make the

conversion a functional vehicle. This needs to be as complete as possible because many little missing things will add up significantly. (To help you calculate and estimate how the center of gravity (CG) will be affected by your choices, I suggest building a spreadsheet that will calculate CG (example is in Chapter 9.) This requires knowing the weight of the object and fore/aft location in the vehicle. For the fore/aft location, I suggest using the front axle as the 0” point from which everything else is measured.

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5.) The rear axle location is simply 0 + wheelbase. Any object in front

of the front axle is a negative dimension. You multiply (weight x location) to get a value (note, added parts are + weight and deleted parts are - weights.) Do this for all the parts and then add all the weights in a total sum of total vehicle weight and add all the weight x location products into a sum. Then divide the weight x location sum by total vehicle weight and you get the location of the CG relative to front axle center.

For an example, we will use our recent Cavalier conversion (Chapter 9). We took the weight of the Cavalier as received without engine, fuel tank, fuel, exhaust system, AC system, and cooling system. We used race car scales to get the four corner weights. The first two entries into our spreadsheet were front axle weight: 1690 lbs and rear axle weight: 951 lbs. Front axle is at 0” and rear axle is 104.1” We then estimate everything we could possibly think about going into and out of the vehicle. For example, we eliminated the spare tire with jack & tools. The weight is coming out so it is negative or -38.9 lbs at 113”. The electric motor is an addition at 156 lbs and is located just forward of front axle or -2” (note the negative location). As you complete this analysis you have a complete Bill of Materials, with a running total of the weight of your conversion and the CG location. You can compare front and rear axle weights to the limits you have set. You can take your model and add passengers & cargo to see where the vehicle is at GVW. But what is really useful is to put the batteries in different locations and see the effect on overall vehicle CG.

0” 104.1” -x” Weight

IN +Plus

Weight OUT

- Minus +x”

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6.) Add and subtract all the above to calculate and set your GVW limit. The differences will tell you how much battery weight you have available to complete your vehicle.

7.) There are things you can do to help yourself gain more reserve for

batteries. Remove content from the vehicle that is not needed, such as insulation materials in the interior or hood blankets for noise control, all the miscellaneous brackets, tubes, hoses, clips, shields associated with a gas engine vehicle. Installing lighter seats or aluminum wheels are other options if available. If you have a 5 or 6 passenger vehicle, you can eliminate the center seating positions and pick up 150 lbs person in the GVW (but make it obvious that those positions are no longer available for seating.) If you need more, you can look at substitute materials for body exterior panels, sometimes the OEM’s will make steel hoods standard but have an aluminum hood for use in heavier models. Just find yourself a good race car guy and ask him what he would do to lighten a car!

Some basic observations.

1.) People like pickups because they can carry a lot of cargo weight (GVW) and have lots of space for batteries. But remember if you substitute 800 lbs of batteries for the 1000 lbs payload capacity, you have a truck that can only carry 200 lbs. But on occasion you can typically exceed GVW for short periods since many manufacturers understand pickup trucks are often overloaded and they are designed for a slight reserve.

2.) EV’s do not carry a lot of “fuel” or energy. The 800 lbs of

batteries is equal to about the energy in a quart of gasoline! (1 gallon of gas is about 125,000 BTU’s or 36.4 kWh) So how can an EV go 40 miles on a quart of energy? EV’s are very efficient where as gas engine powered vehicles are not. Internal combustion engines operate as heat engines and all of this heat generated from the burning of fuel and the friction of the moving parts must be removed; the cooling system and exhaust system do that by throwing it away. The best ICE’s operate at about 20% efficiency or in other words, 80% of the energy is thrown away and does not move you down the road.

3.) Because the energy requirement for moving a vehicle down the road is little, the more work you have to do moving a heavy vehicle

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down the road fast or up the hill eats up your energy quickly. EV’s like to be light weight so they do not consume less energy to move.

This is most apparent when you consider the rolling resistance of your tires. The rolling resistance coefficient relates the force required to turn the tire over with a given load on it. Typical tire rolling resistance coefficients are in the range of 0.010-0.015. This means if you have a truck and it weighs 4000 lbs, the force required to move it down the road is 60 lbs. (4000X0.015). Force is related to work (or energy), which is force times distance, ft-lbs (N-m) and force is related to power, which is force times distance per unit of time, ft-lbs/sec. (N-m/sec or Watt) Note that power is the rate you are doing work so as you go faster you need more power to continue to move. Let’s take the 4000 lb (17,792 N) truck and drive it at 62 mph (100 km/h). It takes 7.4 kW of power to just roll down the road (17792N x 0.015 x 100000m/hr/3600sec/hr/1000W/kW) and 5.9kW at 48 mph (80km/h) and 4.4 kW at 36 mph (60 km/h). So if you are driving for an hour at those speeds, the energy you take out of your batteries to overcome rolling resistance at 62 mph is 7.4kWh, but you did go 62 miles! But that is not all that is coming out of your batteries to move you down the road. Aerodynamic drag is proportional to the square of the speed, the drag coefficient (Cd,) the frontal area, and density of air. Trucks are bad for aero (high Cd) and have large frontal areas. A truck could be taking another 15 kW at 60 mph, 8 kW at 50 mph and 3.4 kW at 35 mph. All these are additive so now your truck doing 62 mph is consuming 7.4 + 15 = 22.4 kW and if you do this for an hour that is 22.4kWh, which means you won’t be able to go for an hour and will probably be limited to under 30 miles.

4.) Size does matter here and the power and energy consumption for a

pickup is 50% more than a subcompact car. Now you know what your trade offs are. (But there are more losses too; there are motor/controller/gear box efficiencies, brake drag, electrical accessory load to just hit the top five. We will not deal with them here at this time. In the examples that follow, you will see why we do the things we do to try minimize these other losses, too.)

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Industry Standards, Guidelines and Federal Safety Standards that should be noted.

1. Federal Motor Vehicle Safety Standards (FMVSS) identify testing conditions and standards for those tests that are all OEM’s are required to satisfy. These can be found at http://www.nhtsa.dot.gov/cars/rules/standards/FMVSS-Regs/pages/Part571.htm Title 49: Chapter V - National Highway Traffic Safety Administration; Department of Transportation; Part 571 Federal Motor Vehicle Safety Standards ; Subpart B—Federal Motor Vehicle Safety Standards 571.101– 571.500

2. SAE (Society of Automotive Engineers, International) publishes engineering guidelines (May 2008), often referenced in FMVSS.

a) J1715 Electric Vehicle Terminology b) J1766 Recommended Practice for Electric and Hybrid

Electric Vehicle Battery Systems Crash Integrity Testing. c) J1772 SAE Electric Vehicle Conductive Charge Coupler d) J1773 SAE Electric Vehicle Inductive Coupling e) J1797 Recommended Practice for Packaging of Electric

Vehicle Battery Modules f) J1798 Recommended Practice for Performance Rating of

Electric Vehicle Battery Modules g) J2288 Life Cycle Testing of Electric Vehicle Battery

Modules h) J2289 Electric Driver Battery Pack System Functional

Guidelines. i) Energy Transfer System for Electric Vehicle – Part 1:

Functional Requirements and Systems Architectures. j) J2344 Guidelines for Electric Vehicle Safety k) J2464 Electric Vehicle Battery Abuse Testing l) J2380 Vibration Testing of Electric Vehicle Batteries m) J2358 Electric Low Speed Vehicles n) J1742 Connections for High Voltage On-Board Road

Vehicle Electrical Wiring Harnesses – Test Methods and General Performance Requirements

o) J1673 High Voltage Automotive Wire Assembly Design.

UPDATE: SAE continues to publish new Standards for Electric Vehicles; please check SAE Standards for new information.

3. IEEE 4. UL

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Chapter 2: High Voltage Safety and Overall Vehicle Safety/Reliability/Durability This is a subject that is critical for all to understand. I will try to provide “facts” by which you can make your own decisions. My purpose is to educate you with my knowledge of what OEM’s are concerned about so at least you will hopefully understand better the compromises you are making and the specific consequences you and others will face. Most of us would like our conversions to be:

1. More than science-fair projects on wheels 2. Reliable so we count on our conversion to do certain jobs for us day in

and day out without wondering if it will complete its mission. 3. Safe to operate reliably both electrically and mechanically, regardless

of weather. 4. Safe as any normal vehicle and if we are in an accident we or anybody

else would not get hurt because of what or how we have done the conversion.

5. Comfortable that if we take riders or children out in our vehicles that we are not exposing them to something that could cause harm to them.

6. Reliable and not require a lot of maintenance and service work or “adjustments” all the time to keep it working. I call it “Plug and Play.”

7. Fail safe enough that if we forget to do something, somebody unknowingly won’t get hurt including ourselves.

These are choices you have to make and if you decide to make trade offs on safety, performance or reliability, then go ahead and do it, but BE AWARE of the consequences that might result for you and others. High Voltage Warnings: High voltage can kill you! IEEE has established that any voltage over 44 V has the potential to overcome normal skin resistance and cause electrical shock. This varies by individual but it is a scientific fact. But it is not the high voltage as much as the current that will kill you. We have all probably worked with 120 VAC electricity in our homes. And have at least once touched the wrong wires and got a shock; maybe even tripped the circuit breaker. Household current is usually on a 15 Amp circuit breaker which limits the current exposure to 15A. In your EV you maybe operating at 120 to 170 VDC or more, but your batteries maybe be capable of putting out in excess of 1000 A! This will kill or burn you if you do something wrong or unintentional.

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Does this mean EV’s are inherently dangerous? No, EV’s can be very safe and perhaps even safer than standard gasoline vehicles but it does not come without significant study, planning and sound execution. If you don’t understand this danger, you will likely get into trouble and not even realize it. Our purpose is to provide you with education so you can do it right and do it with the proper precautions. That is our purpose. What should you do about this? CAUTION and RESPECT are the words. Some basic rules:

1. Get advise or help from “knowledgeable” experts (the issue is what is a “knowledgeable expert?”) I would look into their tool box. If all of their tools are covered in black electrical tape, that is a step in the right direction because they have had accidents and have learned something (hopefully). Check the tools again and see how many are burnt from dropping on high voltage connections, the fewer burnt tools the better unless they are just plain lucky. Last check their hands and see how many burn marks they have from shorting batteries with wrenches in their hands. I have seen people where their wedding rings were literally melted off their fingers (very ugly burn). In fact, many mechanics will take off all conductive jewelry when working with high voltage. Good advice.

2. Never, Never, Ever work alone with high voltage. If you do

something wrong it is important to have someone there who can help you and get you help. Never grab the person being electrocuted, use a non conducting device to break the connection, like a wood broom stick.

I am not trying to scare you, only put the fear of respect into what you are doing. You are working with deadly levels of electricity. With proper precautions, none of this is ever going to happen or cause you any harm.

3. Plan for the worse and then plan to avoid those things. This is basic Design Failure Mode and Effects Analysis (DFMEA). This is a science of understanding what the potential failures could be, the effects of those failures and how to make changes to eliminate those failures. In this case the failure is electrical shock. This science was developed by aerospace and automotive and is used world wide with almost all product design today. For example, we have all dropped a wrench accidentally. It happens to the best of us. If you drop a

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wrench on a battery what are the possible failure modes? The wrench shorts out a battery. A shorted battery like this can deliver 1000A across the wrench and will be very dangerous. It will cause sparks and even flames. It will melt the wrench and if you are holding it, you can get burnt very badly. So now we understand the failure mode and the effects, so how do you prevent this? Insulating all of your connections and battery posts is one preventative solution, eliminating the need to connect batteries with mechanical tools, and possibly wrapping all your tools in insulating materials. And there are other ways that I am sure you can come up with, the issue is there is a need to do something to prevent this failure mode from occurring.

4. Use gloves or better yet use insulated gloves

5. Never put your hands across a potential short – electricity

entering one hand and exiting the other puts the current across your heart, which is not good.

6. Don’t stand in water – since your body becomes the ground circuit

particularly if your high voltage has a ground to earth (and it should not!).

7. Wrap your tools in insulating material – if you drop a wrench you

will not created a short as easily 8. Provide a Master Disconnect Switch for Service – this is used to

open the pack so as to not expose the person doing service to the whole pack battery voltage.

9. Insulate all your connections so as to not leave exposed

conducting connections

10. Simply be careful and respectful of high voltage. It

can kill you. High Voltage Requirements for a “Safe” Electric Vehicle (these are adapted from 1999 EV America Technical Specifications; see bibliography):

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1. Vehicles shall not contain exposed conductors, terminals, and contact blocks of devices of any type that create the potential for personnel to be exposed to 50V or greater. Access to any high voltage component shall require the removal of at least one bolt, screw or latch. Devices considered being high voltage components shall be clearly marked as HIGH VOLTAGE with wiring in orange color or orange sleeving, if at all possible (orange battery cable needs to be specially ordered and then still may not be available in small quantities. I have used orange electrical tape on the ends high voltage wiring. Standard automotive gage orange wiring (10 AWG to 22 AWG) is readily available.) These markings should be installed at any point the voltage can be accessed by the end user.

2. Propulsion power shall be isolated from the vehicle chassis such that

leakage current does not exceed 0.5 MIU (Measurement Indication Units; at 120 VAC at 60Hz: 1 MIU = 1 mA). The human body is less sensitive to higher frequencies, such as what might come out of a high frequency controller, so the current is expressed in MIU (there are devices you can buy to make these measurement, called current leakage testers). To make these measurements, simply place a low current ammeter between potential high voltage and ground on the chassis and ground (earth).

3. Charging circuits shall be isolated from the vehicle chassis such that

ground current from the grounded chassis does not exceed 5 ma at any time the vehicle is connected to an off board power supply in accordance with UL Standards. Read charger section for more information.

4. Vehicles shall be equipped with an automatic disconnect for the main

propulsion batteries. The disconnect device shall operate to isolate the propulsion circuits any time the chassis becomes energized from contact with the propulsion battery or its associated circuits. This disconnect shall be capable of interrupting maximum rated controller currents.

5. A manual service disconnect shall also be required. A decal or label

should be affixed to driver’s sun visor. A similar decal should be affixed to the inside of the vehicle such that it is clearly visible to individuals located outside the vehicle through the lower left-hand corner of the rear window. This disconnect should be operable from the driver’s seated position. It shall require the following capabilities

a. Manual action to break the connection b. The disconnection is physically verifiable

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c. The disconnection does not create exposed conductors capable of becoming energized while exposed.

d. The key-switch may be used to satisfy the operability portion of the manual service disconnect requirement, if it interrupts all control power going to the controller and the main battery contactor(s). This disconnect is not required to operate under load.

6. Safety interlock system – The vehicle shall be prevented from being

driven with the key turned on and the drive selector in the drive or reverse position while the Vehicle’s charge cord is attached. Additionally, the following interlocks shall be present:

a. The controller shall not initially energize to move the vehicle with the gear selector in any position other than PARK or NEUTRL.

b. The start key shall be removed only when the ignition switch in the “OFF” position

c. With pre-existing accelerator input, the controller shall not energize or excite such that the vehicle can move under its own power from this condition.

7. Operation of Hazard lights – Hazard lights should be capable of at least

one hour of continuous operation in the event of shutdown or isolation of the main battery pack or failure of the DC-DC converter system. This subject can be debated; there are two options. First, my recommendation is rather than carry around a weight of a standard extra car battery to provide 12VDC along with its charger, simply use a good reliable DC-DC converter to reduce your battery voltage to a regulated 13.6VDC. Wire the DC-DC directly to the batteries so that it uses half of the pack for voltage & power. Second method is probably safer and involves adding a small SLI battery with the DC-DC tied across the pack to charge the battery. The SLI battery is not a deep discharge battery so your 12V system will be basically powered off the DC-DC anyway. However in case of a high voltage shut down, the SLI could power your hazards lights. The question is if your EV batteries or major system fails and you lose all power, will your DC-DC lose power as well. This may depend on how the DC-DC is wired into the system and what the failure occurrence is.

8. State of Charge Indicator – The vehicle shall include a state of charge

indicator for the main propulsion batteries. Indications should be accurate to ±5% of full scale.

9. Connectors – Low voltage connectors should follow SAE or standard

automotive requirements. High voltage connectors should utilize

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obvious labeling, locking devices, should be keyed to prevent miss-connections, and should be moisture proof.

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Chapter 3: EV Batteries for Conversion Vehicles BATTERIES Now let’s talk about batteries which are where EV’s all begin. Since most of us have limited budgets we are probably looking at lead acid battery technology. What are the issues that need to be considered?

1.) Safety is number one 2.) Availability 3.) Size and weight and ability to package into the vehicle’s available

space. 4.) Long term cost of ownership or life cycle cost based on your

expected duty cycle. 5.) Voltage is a secondary issue since you are trying to balance the

weight limits with the voltage limits. If you can handle 6 volt batteries and get more lead (weight) in then you would get with fewer 12V batteries, use 6V. Lead acid batteries (PbA) have a specific energy that is about 30 Wh/kg. If you are looking for 10kWh of battery energy, then 10000/30 = 333 kg or 735 lbs of battery weight. But remember, more batteries mean more connections and more racks & restraints and usually more problems with battery pack balancing and management.

6.) Charging goes hand-in-hand with any battery pack system design.

This needs to be factored in as well at the front end of the design stage not after it is all done. More on this later.

7.) “Active” Battery monitoring and balancing the pack. Large strings

of batteries should see the same current going through all of them and the voltage should be very close to nominal x number of batteries. If the batteries start to drift apart on a voltage at full charge, you are on the edge of a cliff. There are many reasons why batteries can drift apart. Battery manufacturing variability, age of batteries, particularly if the batteries are not the same age when bought, temperature variation in the batteries (some are in a hotter area or are seeing less cooling, maintenance (if required) is not done correctly to all batteries, or poor charging algorithm is damaging the batteries. You want your entire set of batteries close

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when in full charge or discharged. This imbalance can happen for lots of reasons. Primary reason is the quality level of the batteries you are using and even well known manufacturers have drift in their manufacturing processes over time. My recommendation is to buy batteries from the same lot made on the same day and made relatively recently. You can “cheap” out and use whatever you find lying around but you will get mostly problems in the long run. You may even want to take your voltage meter to the battery store and measure each battery you intend to buy. If one falls outside the others, get another one. How close should they be and be maintained at? Good question. My goal is to keep them within a ±0.1V of each other. Is this easy to do? Absolutely NOT. This gets into a lot of complications but it rests on the battery, charger, and the monitoring system.

8.) What happens when the batteries start to drift apart? First you will

lose range and than the range will get worse. Batteries don’t like two things: 1.) being overcharged or 2.) being over discharged. a. Overcharging will cause gassing within the battery which results

in loss of electrolyte and possibly swelling of the battery case (sealed batteries).

b. Over discharging can kill your batteries to point that they may not return to normal.

c. A typical lead acid battery is considered 100% discharged at 10.5 V. You should never take your batteries to this voltage. About 80% depth of discharge is all you want to use and this is approximately 11.4 V/module (open circuit, no load.)

d. So what happens with an unbalance pack? Your drive-system is expecting a certain voltage and current and if one battery is down in voltage it will deplete more rapidly than the ones around it. This can ruin this battery further or even fail it. As a battery fails it will increase in resistance which lowers the current flow, this commonly is a result of sulphate crystals covering the positive plates or battery running out of water. On the charging side, you can ruin your good batteries. Most chargers charge to certain voltage limits for the whole pack, if one battery is down (your bad one) this will result in overcharging all the other batteries. The charger is looking to charge the entire pack to that set voltage limit, which can cause gassing which releases hydrogen, oxygen and consumes your electrolyte thus reducing the chemical performance of your battery. To see this, let’s say you have a 144VDC nominal pack with 12 PbA flooded batteries. Let’s say your charger charges the batteries to the max limit of 16.2 VDC x 12 = 194.4VDC; but say one battery is down 2V,

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then the others will be charged higher until the pack gets to 194.4 or the other 11 batteries will be charged to 16.4V. This voltage level is above the max limit and will cause more gassing and possible damage to the good batteries. This does not happen immediately but the trend is set and your performance will be a continuous degradation. If this unbalance is not caught early, you may ruin the optimum performance of the whole pack.

9.) “Passive” Battery monitoring – this is a process of monitoring your

batteries and understanding what they are doing. Monitoring is done in operation (watching current and voltages), in charging, and in maintenance modes. A simple way to measure batteries is with a voltage meter. You can build a device with a rotary switch and wires to each battery terminal and can read quickly what the voltage is across each battery. A device like the e-Meter (now Xantrex – Link 10 meter, seen below) is useful for monitoring battery pack functions and provides a good “fuel gage.” It has many useful functions, but it is a simple “passive” monitor not an “active” battery management system.

Selecting Batteries – Factors to consider Update: In 2015 there are many more choices for batteries. In 2008 there were really only 2 battery chemistries for EV’s – lead acid and nickel metal hydride. NiMH batteries were expensive and hard to get. Lithium batteries were not available in forms acceptable for EV conversions. Today, a whole new world has opened up, BUT high quality Li batteries are a major challenge to find and use. I believe that Li batteries with the proper chemistries are the Holy Grail for EV’s and Conversions. Li can provide 3X the energy at 1/3 the weight and last 3X as long. Prices are rapidly coming down as volumes have continued to grow. The major “type of battery” still missing is higher voltage and capacity battery modules, similar to the 12V

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lead acid modules. Modules are mono-blocks with cells in both series and parallel. The World’s automakers are dragging their feet on standardizing and sharing module sizes because they know that high volume, fully automated assembly of modules will drop the price of EV’s drastically. Now back to 2008!

1.) Wet cell or sealed? This is an important decision and one that should be made carefully. In my opinion, there is only one option that is safe for use in a roadworthy electric vehicle and that is a sealed battery. All OEM’s in the world provide sealed batteries in new cars. These are a different kind of lead acid battery since they are used for Starting, Lighting and Ignition (SLI). They are not deep cycle batteries. Many of these are sealed flooded battery technology since they must be low cost. Most after market replacement SLI batteries are sealed as well.

2.) Sealed batteries are usually of two types, gel-cell or absorbent

glass mat (AGM). Both have electrolyte but in a gel cell it is suspended in a gel material and in an AGM the electrolyte is sparsely (starved) stored in a glass mat. Both are sealed valve regulated and can be dropped or cracked and will not spill electrolyte in any position even upside down. Because they are sealed they have recombinant technology which means that the oxygen that is normally produced on the positive plate in all lead acid batteries recombines with the hydrogen given off by the negative plate. The “recombination” of hydrogen and oxygen produces water, which replaces the moisture in the battery. Therefore the battery is maintenance free and never needs watering. Never mess with the valve regulator, never open the batteries, and never overcharge the batteries. Do not buy “additives” to restore bad/ruined batteries. If you do this, all bets are off on your batteries. Just leave them be and they will work great for you.

3.) Gel battery or AGM? Both share similarities but gels have better

deep cycle life, superior shelf life, very rugged & vibration resistant, better temperature resistance or less temperature sensitivity, and offer the lowest cost per cycle (cost/life cycles). Gels are higher initial cost, heavier, and require a voltage regulated charger and do not want to be overcharged. If you want to build a dragster and want high power (or the ability to deliver high current discharges); Gels are not the right batteries for dragsters. AGM’s offer lower initial cost and can accept higher charging voltage than a gel battery but they do have shorter life cycle in deep cycle

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applications. All these issues are a function of how you use your batteries. Many claim impressive long lives and long mileage lives out of their batteries. This depends of how deeply you discharge your batteries. Most lead acid will do 400-500 cycles at 100% depth of discharge.

4.) Lastly, there is always new technology being developed and the

science is always changing and improving. What is good today may not be the best tomorrow. There is much interest currently in Li-ion batteries, but in the last few years, the chemistries and technologies have improved tremendously and continuously.

5.) Wet cell batteries – The International Society of Automotive

Engineers, SAE has about 50 standards which involve electric vehicles. These standards are developed over time and are updated or eliminated if they become outdated. There are references to SAE standards in most Federal Motor Vehicle Safety Standards (FMVSS). Wet cell batteries are very difficult to make compliant with these international safety standards. First, there can be no leakage into the passenger compartment including while conducting the roll over procedure following all crash tests. You are limited to 5 liters from everywhere else. We are converting automobiles for use on public roads and with that we have certain responsibilities to ourselves, our occupants and those around us. We are not building golf carts or fork lift trucks. Cars get into accidents and people can get hurt. Cars operate in a variety of weather and road conditions. People do a variety and sometimes strange things with their vehicles. We need to recognize these issues and make the proper decision for battery selection.

a. With that said, flooded lead acid batteries are not sealed, ever.

Adding a watering system does not seal the batteries. The sulfuric acid is in a liquid solution and moves around. Flooded lead acid batteries can never be mounted other than vertical because the electrolyte will leak out. They can not be sealed because of the gases released during charging and discharging. The water breaks down into hydrogen and oxygen and escapes.

b. What happens when a battery is turned over, as in an accident?

They will leak acid and this can be in direct violation of SAE standards and FMVSS requirements (see FMVSS 305 for EV electrolyte spillage, battery retention, and electrical shock protection.) If a battery is hit directly and the case cracks, most of the acid will leak out. If they are in a crush zone in a crash,

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they can literally exploded and spray acid everywhere. Sulfuric acid is considered to be a hazardous material. In a car battery the typical concentration is about 60% water and 40% sulfuric acid. In addition, the solution also has lead concentrations in it as well. When sulfuric acid comes in contact with human flesh, it withdraws water, leaving a black charred carbon residue, in place of living tissue. If you disagree, please read the MSDS (material safety data sheets) that all battery producers issue.

c. Sulfuric acid is not flammable by itself but it can cause and

support a fire by reacting with other chemicals/materials and liberating enough heat and/or hydrogen to ignite ordinary combustibles and even cause an explosion.

d. What if I put the batteries into a sealed container? The

container can not be sealed because you must release the hydrogen and oxygen generated during discharge and recharge or you can have an explosion if a spark occurs. (Never put an open/non-sealed contactor in a battery box!)

e. Another issue with flooded batteries is the release of sulfuric acid

outside the batteries, basically fumes. This residue can ionize materials around it and conduct electricity from the battery. So now you have your battery grounding to your car! These fumes also corrode everything in sight, particularly your battery terminals, cables, crimps and restraints. If you use metal strapping to retain your batteries, these can cause shorts you never even dreamt of.

f. But my biggest concern is crash-worthiness. FMVSS requires

that cars sold to the public by a manufacturer must comply with FMVSS standards. The tests are numerous, but basically the major tests are 30 mph front and angle barrier impacts, 30 mph rear moving barrier impact, and side impact. After these tests there is a small amount of acid that can leak and then the vehicle is rolled over with the same limits on total leakage. It is virtually impossible to meet these standards with a flooded lead acid battery in an EV conversion. These are not arbitrary standards but are standards developed to offer reduced injury to people in accidents. If you review the NHRA rules for drag racing both open wheel vehicles and motorcycles are not allowed to use anything but a sealed battery. Other vehicles require the batteries to be in a sealed fully enclosed container that will not expose driver/people to its contents in event of an incident. In

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these cases the dragsters open the battery containers when charging and when they are running, they run only for a few minutes.

g. MY RECOMMENDATION IS TO AVOID FLOODED LEAD ACID

BATTERIES IN A CONVERSION. Will flood lead acid batteries power the car? YES. Are they road-worthy? NO! This is your decision and now you know the consequences.

Where do I put the batteries?

1.) As you determine your battery choices, this will become clearer, but here are more things to consider.

2.) Maintain vehicle GVW and weight distribution. A large part of

vehicle handling is weight distribution. If you start with a vehicle that has 60% front/40% rear weight distribution and end with 40% front/60% rear, you have changed the handling of the vehicle tremendously. Is it still drivable? Yes/Maybe, but it will not do all things the original car was designed to do. A heavy rear biased car may under certain conditions want to spin the tail out in turns (oversteer.)

3.) Don’t put all the batteries at the front and/or rear end of the

vehicle, this too will affect handling. This creates a high polar moment of inertia, which is what you have to overcome in order to turn into a corner quickly. A car with high polar moment of inertia will seem like a boat going into a corner. If at all possible try to locate the batteries as centrally as possible but exterior to passenger compartment. This provides the other benefit of putting the batteries in the same area as the passengers who you are also protecting with the crash structure that was originally designed. Protect the people, protect the batteries. Putting the batteries in the front or rear end has the potential for crash safety issues. In a crash the vehicle crumples to absorb the energy of the impact, thus softening the deceleration of the vehicle and reducing the injury forces the occupants see. If your batteries fill the crash zone, including the battery racks to hold the batteries, then you are potentially preventing the vehicle’s structure to crumple and will transmit higher forces into the passenger compartment which the passenger compartment may not have been designed to with stand.

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4.) Battery pack containers, trays or racks. There are lots of ways to do everything and many work quite well. Here are guidelines I would suggest that you consider.

a. Now that you know where you want to put your batteries, how

do I hold them in place? They must be restrained and restrained safely. If you answer, “I don’t get into accidents, I don’t really care, It’s not that important;” You are WRONG. I have seen examples on the Internet where somebody takes out the back seat, lays down a piece of plywood and lays flood lead acid batteries on the plywood and then wires them together...and that is all. This is so incredibly dangerous! Say your batteries are typical EV batteries and weigh 70-80 lbs each. You hit something or someone hits you and you stop abruptly at 10g’s (this is mild accident). Your 80 lb batteries are now flying with a force of 800 lbs. I would not want to get hit by an 800 lb object and your battery wiring will only slow them down a little.

b. Batteries need to be restrained and secured to the vehicle’s

structure. Again this means that the tray or support holds them in position and secures them from being ejected in all directions. Most batteries have features molded into the case that allows hold down provisions, consider using these if possible. For additional security I would recommend some form of hold down over the top of the batteries as well (this can be a strap, or a full cover.)

c. Since weight is all important, I would not recommend going to

the junk yard and picking up steel scrap and welding/bolting it all together. Think about the supports and what they have to do and you will probably come up with a better, but lighter solution. Steel is easy to weld so it is usually used. Use the section properties of the steel not just the gage. Rather than building the support with 1½” angle ¼” thick, think about 16 gage (0.063” thick) 1” square tube with a 16 gage flange welded to the bottom to rest batteries on. This will be lighter, stronger and less than half the weight. You could also weld a Z flange for the perimeter frame with cross tubes of thin gage to stabilize. If aluminum is available, use it because it will be half the weight. Another solution could be to make the tray out of fiberglass or fiberglass sandwich, if you can. Fiberglass is not reactive with the battery acid. SEE PICTURE ATTACHED??

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d. Insulating the tray for cold weather. The issue is how cold do you want to operate the vehicle in? I prefer to store the vehicle in the winter in a garage if available. If you want to operate below 0oF and have the vehicle sitting outside in that weather, you are probably in the wrong climate. EV’s like warm weather and in very cold weather the batteries lose capacity quickly. Battery heaters can be used but usually only when charging and power is available to power the heaters. (A group 31 battery can be heated with either a silicon heater pad on the bottom or with a wrap around the sides. These heaters require 50W-80W each at 120VAC. With 12 batteries that is 600W to 1000W of power required. They must be thermostatically controlled to typically 75o - 80oF. You obviously need them in an insulated box to avoid heat loss. So can you use your traction batteries to power your heaters while you are at work? A lot depends on temperature, insulation and heater controls. My suggestion is probably not but it depends on many things. Build it, measure it, and decide for your self, but remember you have precious little energy to spare and EV’s do not operate as efficiently in cold weather, regardless of the battery issues.) If you put the batteries in a box (and it can’t be sealed,) it must be able to vent out the hydrogen if released. Be careful to not overheat the batteries as to boil off the electrolyte and remember in summer to take the insulation out so again as to not overheat the batteries.

e. My recommendation is to allow the batteries to vent naturally to

the atmosphere through natural convection and avoid stacking the batteries so that no air can flow around them. Batteries operating at different temperatures will age differently and eventually drive voltage imbalance in your pack.

Battery Facts to help you:

1.) How much useable capacity does a battery have, based on standard specifications given? The first thing I learned working with battery manufacturers and on the General Motors EV programs was, “there are liars, damn liars, and battery engineers” (this is a joke, of course, but it illustrates that you need to be careful reading and understanding the data that battery companies provide.)

2.) Typical data (or standard data) are:

a. Model number

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b. Nominal voltage of the module c. CCA (cold cranking amps) @ 0oF

d. MCA (marine cold cranking amp) @ 32oF, (cold cranking amps

are the maximum number of amps that can be pulled from the battery until 1.2 V per cell is measured and the cell is 100% discharged under load)

e. Reserve capacity is a standard BCI (Battery Council

International) battery test that all lead acid battery manufacturers subscribe too. It measure the minutes of reserve capacity with a 25A load until the battery reaches 1.75V per cell or 10.5 V with a 12V module

f. Nominal capacity at C/20. This is the critical measurement for

predicting range of the vehicle. This tells you how much energy your battery can store which translates into how far you can drive it on a full charge. Manufacturers of deep cycle batteries usually will provide other capacities at various discharge currents using the term C. C/20 is the current that can be drawn for 20 hours. C/5 is the current that can be drawn for 5 hours. (For example a battery that has a C/20 capacity of 100 Ah (Amp-hours) will allow 5A to be withdrawn for 20 hours). In an EV application with lead acid batteries running continuously, you are most interested in looking at C/1 or C/2 rates (1 to 2 hours of continuous operation). Many times this is not available, but IT IS VERY IMPORTANT TO UNDERSTAND. Battery capacity “shrinks” at higher discharge levels, meaning the faster you discharge them the less usable energy they hold. For example the 100 Ah battery at C/20 (5A discharge) will be about a 55Ah battery at 100A discharge (C/0.55 or 33minute discharge)...significantly different. See Peukert’s Equation below for how to approximate what you want.

g. BCI case size, which is a set of standard battery dimensions that

the whole industry uses. This standardization allows you many different manufacturers making a “size” interchangeable battery.

h. Dimensions are usually given is length, width, and height. Be

careful to understand on the height measurement how this is made and whether the terminals are part of this or not.

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i. WEIGHT, the all important measurement. Everything being equal, more weight means more lead and more lead means more ability to store energy.

Peukert’s equation: Peukert's Law, presented by the German scientist W. Peukert in 1897, expresses the capacity of a lead-acid battery in terms of the rate at which it is discharged. As the rate increases, the battery's capacity decreases, although its actual capacity tends to remain fairly constant. Peukert’s constant (dimensionless) reflects this non-linear characteristics. It is not exact but fairly representative of what to expect. Typical constants are in the range of 1.1 to 1.3 and vary with battery, even if same materials are used. Larger plates, heavier plates reduce the effect somewhat and aging increases the effect and the constant. More commonly, manufacturers rate the capacity of a battery with reference to a discharge time. Therefore, the following equation can be used: t = H/((I * H)/C) ^ k Where:

t is the hours to discharge at new discharge rate of I, Amps H is the hour rating that the battery is specified against, such as 20 hr

rating C is the rated capacity at H, such as 100Ah capacity at 20 hr discharge

rate I is the discharge current in Amps that you want to know battery

capacity k is Pueket’s constant

For an ideal battery, the constant k would equal one; in this case the actual capacity would be independent of the current. The Peukert law becomes a key issue in a battery electric vehicle where batteries rated at 20 hour discharges are used(discharged) at much greater rates in about 1-2 hours. An electric vehicle usually will be able to operate for 1 to 2 hours before needing to be recharged. Percentage of Available Capacity from a 100Ah Battery at different discharge

rates using different Peukert exponents

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Discharge Rate in Amos C/→ 20 10 6.0 4 2 1.3 1 0.5 0.4 0.3 0.25 0.2

n 5 10 16.7 25 50 75 100 200 250 300 400 500 1 100 100 100 100 100 100 100 100 100 100 100 100

1.1 100 93 89 85 79 76 74 69 68 66 65 63 1.2 100 87 79 72 63 58 55 48 46 44 42 40 1.25 100 84 74 67 56 51 47 40 38 36 33 32 1.3 100 81 70 62 50 44 41 33 31 29 27 25 1.5 100 71 55 45 32 26 22 16 14 13 11 10

For example: A 100Ah battery with a Peukert exponent of 1.25 will deliver on 47% of its capacity (47Ah) when supplying a 100A load or being discharged at C/1 rate. Anothere example: A 200Ah battery being discharged at 50A until fully discharged (equivalent to a 25A discharge on a 100Ah battery) If the battery delivered 72% (144Ah) the Peukert’s exponent would be 1.2 Let’s look at a more realistic application and comparision. The Cavalier EV Conversion has a gel cell battery rated at (C/20) of 97.6 Ah (close to the 100Ah in chart). In real applications the vehicle will go about 50 miles or have a run time 1-2 hrs. The C/1 rate is 64.5 Ah (measured) which indicates Peukert exponent of about 1.15. Now, let’s say that I wanted to do some drag racing and was setup to be able to pull a 500A draw (and that batteries could deliver that), going to the chart you can see that the battery is capable of delivering only about 50Ah. In terms of a fuel tank analogy, your fuel tank shrinks as you pull fuel faster out of it! Battery State of Charge (SOC) or depth of discharge (DOD) These are ways to figure out how much more driving you can do before your batteries are empty. Your EV “fuel gage” measures Watt-hours of energy. Watt-hour counters can be programmed with battery capacity, Peukert’s exponent, and other particular batteries characteristics. They then count watt-hours and can display various information relating to the state of charge of the battery pack, including remaining energy and thus range, which is what the Link 10 meters do. Other methods include direct voltage measurement, specific gravity measurements, current measurements. All have some significant limitations and all change over time particularly as the batteries get older.

1.) Direct voltage measurement: This uses the voltage of the battery cell as the basis for calculating SOC or the remaining capacity. Results can vary widely depending on actual voltage level, temperature, discharge rate and the age of the cell and

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compensation for these factors must be provided to achieve a reasonable accuracy. If you look at a graph of open circuit voltage versus residual capacity, you will note for a high capacity Lead Acid cell, the cell voltage diminishes in direct proportion to the remaining capacity. Some batteries drop off faster than others which mean you are losing power or speed as the battery discharges. Voltage is not a good predictor of range left or of charge left, but it is good to know when it is time to quit driving and recharge.

2.) SOC from Specific Gravity (SG) Measurements - This is the customary way of determining the charge condition of flooded lead acid batteries. It depends on measuring changes in the weight of the active chemicals. As the battery discharges the active electrolyte, sulphuric acid, is consumed and the concentration of the sulphuric acid in water is reduced. This in turn reduces the specific gravity (SG) of the solution in direct proportion to the state of charge. The actual SG of the electrolyte can therefore be used as an indication of the state of charge of the battery. SG measurements have traditionally been made using a suction type hydrometer which is slow and inconvenient. Nowadays electronic sensors which provide a digital measurement of the SG of the electrolyte can be incorporated directly into the cells to give a continuous reading of the battery condition. This technique of determining the SOC is not normally suitable for other cell chemistries, particularly sealed batteries. Again this is not a predictor, but current status reading.

So what is the best way to implement a fuel gage? A gage that can integrate the current draw over time with a Pueket’s constant is best to predict energy used/left. But unlike your gasoline car, if you drive hard your EV energy drops faster. Watch your fuel gage, always reset your trip odometer each time you charge, and watch your foot on the accelerator pedal. As you drive more and more you will become comfortable with the range you can expect. The other instrument that can help you is the current you are drawing (Link 10 has this as a display option). If I knew more about the vehicle’s tachometer, I would convert this to be an ammeter so you could tune your driving style to minimize current draws. Final Words of “Wisdom”

The answer to 90% of the questions about EV’s can be answered quite simply, “It’s the batteries, stupid.”

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Chapter 4: EV Chargers for Conversion Vehicles

What are the requirements for a charger?

1. First question is on-board, off-board or maybe both. I believe the on-board charging option is mandatory due to limited range a conversion will have, particular with lead acid. Off-board is very limiting. But a low power on-board and a high power off-board may make sense, if you can afford it and find them.

2. What power level? There are standards for three levels of charging for

the consumer. a. Level 1 charger is 1kW and is good for 120VAC @ 15A household

circuit. b. Level 2 charger is 3kW and is good for 240VAC @ 15A circuit c. Level 3 Charger is 6kW and is good for 240VAC @ 30A dryer

circuit. These are guidelines and you can really use anything you want, just remember if you want to charge your batteries away from your house, will there be a receptacle to plug into?

3. There are detailed Underwriters Lab specifications for chargers, and SAE has them too. I would follow SAE because they were written around automobiles and they reference the other standards.

4. A key issue with chargers is electrical isolation. What does this

mean and why is it important? The charger should be electrically isolated from the vehicle chassis such that ground current from the grounded chassis at any time while the vehicle is on charge or the charger is connected to an off-board power supply does not exceed 5 mA. This minimizes potential shock when touching the vehicle. To test this all exposed conductive surfaces of the charger and vehicle frame should be evaluated. With the charger plugged into the wall, measure current flow (leakage current) from the vehicle to the return and ground circuit of the plug (this is the white wire in the cord and the green wire. In 220 V, it is the while wire; the black and red carry 120V phases, and some 220V lines will also have a green ground)

5. Leakage current defined: “Leakage current” is a generic term applied

to any form of unwanted currents. “Leakage current” or more accurately, “touch current” as it relates to electrical shock hazards is the current that flows to ground through the human body due to inadequate insulation or improper grounding between internal supplies

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and accessible conductive parts. Since the human body’s reaction to electrical shock depends on many variables, one of which is the frequency of the current being experienced. Human body is less sensitive to higher frequencies so sometimes the unit, Measurement Indications Unit (MIU) is used to correct for frequency. But for standard 60Hz current a 0.5 MIU is equivalent to 0.5 milliamps (0.5mA) which is the same for DC currents. Burn hazards can occur at 70 mA and this is considered the safe limit to prevent leakage current related electrical burns.

6. High voltage connections – there shall be no non-insulated connections

that could expose people to high voltage on the outside of the charger (high voltage is defined as any voltage greater the 42.4V)

7. Weather protection – Chargers are usually mounted outside the vehicle

both for cooling of the electronics inside the charger and to prevent occupants from accidentally touching high voltage or touching a high temperature surface on the charger. This would mean that the charger needs to be environmentally sealed. If the charger were to overheat or fail and catch fire, the damage would be contained outside the vehicle. The charger should not have ventilation holes that would allow water to enter the charger, either in operation on the road (prior to charging) or in stationary operation while plugged in for charging.

8. Wiring to the batteries and to the wall plug should have sufficient

insulation to prevent electrical shorting of the wires and should be wire gauge sufficient to carry the charger input and output currents.

9. Input Power: the plug configuration should be compatible with

standard wall outlets, 120VAC or 220VAC including a ground circuit. The charger should be able to handle from standard 60Hz to 50Hz alternating current. Ground fault circuit interrupters (GFCI) are not required.

10. Vehicle charger connections – the type, size and location of the point

of the vehicle should be described and identified. It should be designed so that convenience is in mind for the operator. The outlet or plug should accept common extension cords of proper gage based on current and distance.

11. Vehicle shall be prevented from being driven with the key turned on

and the drive selector (gear shift) in forward or reverse while the vehicle’s charge cord is attached. In addition:

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a. Controller shall not initially energize with the charger plugged into the wall.

Not directly related to the charger but important safety issues are:

b. Controller shall not initially energize to move the vehicle while the vehicle is in other than neutral.

c. Controller shall not initially energize if there is a pre-existing

accelerator input.

12. Should be able to charge completely in less than 12 hrs 13. True power factor of 95% or greater and harmonic distortion rated at

≤ 20% (current at rated load). This is important from the standpoint of the chargers effect on the utility grid and really is only applicable to higher power charging stations. These goals are still good and should be achieved even at lower charging power levels.

14. Charger should be fully automatic determining end of charge

conditions are met and transitioning into a mode that maintains the main propulsion battery at a full state of charge while not overcharging it, if continuously left on charge. The charger does not need to have an on/off switch which is why it should be automatic. It is not acceptable for the charger to need active adjustment, control and monitoring by the end-user of the charger. This is a science-fair project approach and not true automotive “plug and play” approach. When people can adjust things (other than perhaps the initial set-up of the charger), they have the potential of messing up the charger and battery charger algorithms which could result in improper charging of the batteries that could lead to more serious problems, such as overcharging and releasing explosive hydrogen gas.

15. The charger should have over-load protection. This would be in the

form of a fuse or circuit breaker. Access for replacing or resetting requires removal of the cover of the charger (be sure the charger is unplugged and disconnected from the batteries before do this. Understand why the overload circuit was tripped before resetting the charger.

16. Operator visual information shall include lights or something to

indicate the status of the charger. The lights should indicate the charger is plugged into an AC outlet. The lights should indicate when

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the charger is charging and when it is complete. Having no lights is not a good way to indicate the charger is finished.

17. Acceptable operating temperatures for the case: Per UL, the case and

surrounding parts should not exceed 140oF. Final note: There are a large variety of chargers available for the conversion market. Most of these “work” but most are not plug-and-play. Many are not isolated, many require constant playing with adjustment, very few do any battery pack management, many have exposed connectors, etc. At least I have tried to tell what to look for, so whatever ever you buy, you now know the consequences of your decision. UPDATE: With Lithium ion batteries there has been a lot of work done to develop Battery Management Systems (BMS). These complex systems are designed to insure the batteries stay in balance and are not over charged or over discharged. With some of the poor quality and inconsistent performance from lower cost batteries, these BMS units have been the “fix” for poor quality. The people who design them will never agree to test systems with and without their BMS units which I find interesting. I believe as the World gets to higher volume, automated assembly systems, that batteries will become higher quality and more consistent in performance. I believe the need to monitor on an individual cell basis will stop and the BMS will be used to adjust primarily for temperature differences in larger packs and to perform some higher level balancing need. The key issue with Li batteries is whether the failure mode is open or shorted? Lead acid almost always fails, open. Some Li chemistries can fail shorted which can create a thermal hazard. Choose wisely if you go the Li route.

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Chapter 5: Drive Systems for EV Conversions The drive system is defined as motor, controller, transmission, batteries, and charger. The drive system is what makes an electric vehicle, drive electrically. We cover many of these parts separately, so in this part of the guide, we will talk about the motor and how the power gets to the wheels and moves the car (usually a transmission system). Our conversion is basically a plug-in battery electric vehicle (BEV). This is in contrast to hybrid electric vehicles (HEV’s) which retain the ICE (Internal Combustion Engine) and uses the ICE to propel the vehicle and charge the batteries, while the electric motor can supplement the mechanical drive system and capture regenerative braking. There are numerous types of hybrids, but basically fall into two or three classes. Parallel hybrids use both the ICE and electric motors to propel the vehicle. Series hybrids use only the electric motor with batteries and the ICE is designed to run a generator to charge the batteries when they require recharging. The generator system is designed to generate enough power to run the vehicle continuously until it runs out of fuel. Lastly there is a combination of the series and parallel systems that functions in transition between the two. Toyota’s Synergy Drive in the Prius is such a combination. Fuel cell vehicles (FCV’s) are also electric vehicles where hydrogen is used as a fuel to power a fuel cell which generates electricity to charge batteries or super-capacitors and provide electrical power to the motor. Motor choices for today There are several types of motors, but the one that remains the most common, available, and affordable is the series DC brushed motor. These are good choice today but with time, we hope to see better technologies become more affordable. The list is (in increasing levels of efficiency):

1. Series DC brushed motor 2. Separately excited DC brushed motors 3. AC induction motors 4. Permanent magnet DC brushless motors

The development of the electric motor has provided us with one of the most efficient and effective means of accomplishing work that man has ever seen. Without electric motors, many aspects of our current civilization might not have been possible. Electric motor principle is relatively simple in that it converts electrical energy into mechanical energy. I will just cover some

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basics and there is a lot more information available, but this will provide some background and understanding of motor basics including magnetism, DC motor theory, construction and components, basic DC motor terminology, as well as define several different types of DC motors.

Magnetism

It is commonly known that magnets will attract various types of metal when held in close proximity. The magnet does this because of a common force called a "magnetic field". "Lines of Flux" typically help show a visual representation of magnetic fields. The stronger the magnetic field, the more lines of flux will be shown. Lines of flux are always drawn directionally to shown the distinct movement from North pole to South pole.

Magnetic principle in an electric motor can be represented by visualizing a permanent magnet and a simple electromagnet created with a single winding and a small battery. Place the permanent magnet which has a permanent and distinct North pole and South pole fixed and in close proximity to the electromagnet wire coil . Run current through the electromagnet to create a South pole and a North pole. The permanent magnet will exert a magnetic field which with a little help to start the electromagnet coil, will start to rotate. In magnetism, similar poles repel each other and opposites attract. So, naturally through the laws of magnetism, the permanent magnet wants to attract and repulse the wire’s electromagnetic field. Once it starts turning, the force of attraction between the unlike poles becomes strong enough to keep the magnetic field rotating. Once stopped, the unlike poles line up, the rotor would normally stop because of the magnetic attraction between them.

This is a very simple motor – two parts and a battery! Our explanation is also simplistic of how a magnetic field causes an electric motor to turn, and real life motors are much more complex, but the principle is the same.

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AC vs. DC Magnetism

Reversing the magnetic polarity in electric motors varies in principle between AC (Alternating Current) and DC (Direct Current) motors. With DC power, the current always flows in one direction and with AC, the current flow direction changes periodically. In the US, the most common form of AC power is what flows through your house and is 120 VAC (Volts Alternating Current) 60 Hz. This means that the current flow changes direction 120 times per second. This can also be called 60 Hertz AC. This is named after Mr. Hertz, who first thought of AC current. I will not cover AC motors, but typical simple AC motors run at some multiple of the 60 Hz switching frequency. 60Hz is 60 cycles/per second or 3600 cycles/min. Many AC motors run at 1800 rpm or 3600 rpm. I will leave AC motor theory at this point. Lots of information is available for you to read else where.

DC Motor Theory

The first motors were called dynamos from the Greek word dynamis which means power. "Motor" comes from the Latin word "motus" which means one who imparts motion. The dynamo was not invented by one person, and was a mass collaboration of many people, from many different places around the world.

Motor Basic Principles

To change mechanical energy into electrical energy, i.e. a generator, you need to move a conductor through a magnetic field. The opposite is also true. If electrical energy (current flow) is applied to a conductor in a magnetic field, a mechanical force and mechanical energy will be produced as we did with our simple motor above.

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DC Motor General Composition and Construction

Typical DC motor or generators are composed of basic components which we'll define below: an armature, an air gap, poles, and a yoke which form the magnetic circuit; an armature winding, a field winding, and a commutator which form the electric circuit; and a frame, end bells, bearings, brush supports and a shaft which provide mechanical support.

NetGain Technologies, Warp Motor

• Armature Core or Stack: The armature is made up of thin magnetic steel laminations stamped from sheet steel by a die. Slots are punched in the laminations with another die. The laminations are welded, riveted, bolted or bonded together. The armature is the central portion of the motor which spins inside the field as represented by the permanent magnet in our fist basic example earlier.

• Armature Winding: The armature coil is the winding, which fits in the

armature slots and is eventually connected to the commutator. It either generates or receives voltage depending on whether the unit is a motor or a generator. The armature usually consists of wire, either round or rectangular and is insulated from the armature core.

• Field Poles: The poles are made from solid steel castings or from

laminations. At the air gap, the pole usually fans out into what is know as a pole head or pole shoe. This is done to reduce the reluctance of the air gap. Normally field poles are formed and placed on field pole cores and then the whole assembly is mounted to the yoke.

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• Field Coils: The field coils are windings, which are located on the poles and set up the magnetic fields in the machine. They also consist of copper wire and are insulated from the poles. The field coils may either be in shunt windings (in parallel with the armature winding) or series windings (in series with the armature windings) or a combination of both.

• Yoke: The yoke is a circular steel ring, which supports the field, poles

mechanically and provides the necessary magnetic path between the pole. The yoke can be solid or laminated. In DC units, the yoke also serves as the frame.

• Commutator: The commutator is the mechanical rectifier, which

changes the AC voltage of the conductors to DC voltage. It consists of a number of segments normally equal to the number of slots. The segments or commutator bars are made of silver bearing copper and are separated from each other by mica insulation.

• Brushes and Brush Holders: Brushes conduct the current from the

commutator to the external circuit. There are many types of brushes. A brush holder is usually a metal box that is rectangular in shape The brush holder usually has a spring to keep the brushes firmly in contact with the commutator. Each brush usually has a flexible braided copper shunt or pigtail which extends to the lead wires. The brush assembly is often insulated from the frame and is made as a movable unit about the commutator to allow for adjustment.

• Frame, End Bells, Shaft, and Bearings: The frame and end bells (caps)

are usually steel, aluminum, or magnesium castings used to support the basic machine parts. The armature is mounted to a steel shaft, which is supported between two bearings. In many golf cart “3/4 motors”, the second bearing is often located inside the differential as part of the differential input shaft.

Typical Golf Cart Motor ready to attach to rear axle assembly

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Armature Windings

Armature windings can be a very complex topic and I will leave that for you to pursue further. One issue I do want to mention is a quality issue. A high quality motor will be balanced and trued before assembly. This means the armature air gap is consistent and uniform. The armature is sealed and coated to prevent the windings from moving even at full rated speed. Lastly the armature is balanced dynamically to run smooth with minimal vibration. Many motor manufacturers to cut costs don’t balance their armatures, hoping that by consistently winding them, they are close enough. Sometimes this shows up as “noise” in the transmission, when in fact it is all motor induced.

Field Windings

The field windings provide the excitation necessary to set up the magnetic fields in the motor/generator. There are many types of field windings that be used in either motors or generators. In addition to the following field winding types, permanent magnet fields are also used on some DC applications (both brushed and brushless).

• Series Wound motors have the armature connected to the field in series. To get high magnetic field, the field winding is large gauge wire with just a few turns maybe as few as 6. Torque and speed control are achieved by a throttle that varies the current flowing through the field and the armature. Series motors offer very high starting torques and good torque output per amp, but have generally poor speed regulation. DC motors like all motors have high torque at low speed and decreasing torque as the speed increases. In fact, it is current that determines torque and voltage that controls speed. Speed of DC series motors is generally limited to 6,000 rpms and below (there are always exceptions). Series motors should be avoided in applications where they might "lose their load" (stepping on the clutch and exciting the throttle) because of their tendency to "run-away" and exceed max rpm under no-load conditions. Never run a series wound motor in a no-load situation. Series wound motors are the industry standard in golf carts, industrial vehicles, and EV conversions. However the industries are changing tremendously with newer technologies. Separately excited motors are becoming the standard in golf carts today and the motors were introduced in the mid-90's. AC motors are starting to take over the industrial fork lift truck world due to higher efficiencies and long run times.

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• Straight Shunt Wound motors, with the armature shunted across the field, offers relatively flat speed characteristics. Combined with controlled load speed, this provides good speed regulation over wide load ranges. While the starting torque is somewhat lower than the other DC winding types, shunt wound motors offer simplified control for reversing service. This winding is connected in parallel with the armature, Shunt windings usually consist of a large number of turns in a small size. This is a good winding for reversing since it provides the same amount or torque in both directions. Shunt wound motors often have a rising speed characteristic with increased loads.

• Separately Excited Winding used in DC brushed motors (SEPEX) are a

unique type of DC brushed motor with a separately excited armature and stator windings. In a series motor, these windings are in series and you will see large wires making both the stator and armature windings. The motor works because of a magnetic field created by passing current through these windings. This magnetic field is a function of current and number of winding turns around the stator. With a separately excited motor, the electronic controls can adjust the current to the stator separately from the armature. This results in a “variable speed/torque” motor. A SEPEX motor can have very high start-up torque, but by field weakening with motor speed, also achieve higher motor speeds (with less torque). SEPEX stator is made of much small diameter wire but many more turns. SEPEX motors with their controllers can provide regenerative braking easily and safely to the motor. Unfortunately, there are not a lot of these motors and controllers available in the sizes we need to do an EV conversion. They are more expensive to make and consequently the industrial world prefers cheaper is better. Separately excited motors are a type of shunt winding and many modern golf carts and Low Speed Vehicles use these.

• Compound Wound (stabilized shunt) motors utilize a field winding in

series with the armature in addition to the shunt field to obtain a compromise in performance between a series and shunt type motor. This type offers a combination of good starting torque and speed stability. This is also known as compound excitation. The series winding can be designed as a starting series only or as a start and run series.

• Stabilized Shunt Winding is similar to the compound winding, this

winding consists of a shunt winding and a series winding. The series or stabilizing winding has a fewer number of turns than the series winding in a compound wound machine. It adds to the torque of one

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direction of operation and subtracts in the reverse direction of operation and in regeneration (half speed reverse and regenerative braking).

AC induction motors AC induction motors have the greatest potential because of the existing production capability in the World today building AC motors. Literally everything we own with an electric motor runs off of household AC current. In industrialized countries it is estimated that 65% of the energy consumed comes from operating AC motors. There are 100’s of millions of motors built daily around the globe. These go from the very small to the very large in size. There are many kinds of AC motors. Wikipedia.org is an easy source to read to learn more. However, the 3-phase AC induction synchronous motor is the one of choice for EV’s and electric drives. Almost all AC motors in use daily are oversized, under-rated in order to be air cooled by ambient conditions. Once we get into electric vehicle drive motors, cooling becomes an issue as weight and size become increasingly important. AC drive motors are starting to take a foothold in industrial electric vehicles, like fork-lift trucks. The golf cart industry is starting to look at AC drives, too. AC drives can be more efficient and reliable with lower maintenance requirements than DC brushed motors. AC motors require a more electronically complex controller, but with mass production and our computer manufacturing capabilities, the prices will fall. The feature that I find desirable is regenerative braking, which is very easy to do with an AC motor. Motor Selection What you need to do is figure out your specifications for performance. These would include:

1. How heavy is the vehicle with batteries and driver

2. How fast is top speed 3. How fast to acceleration 0-60 mph 4. What grades (how steep is the hill and how long is the accent) do you

need to climb and at what speed; typical specification is climb a 3% grade at a sustainable 55 mph and climb a 6% at 45 mph with two 75 kg people starting at 50% State Of Charge (SOC).

5. How far to travel on a charge

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• If you are trying to build a dragster, you need a different guide than this

one. • If you want to build a race car, you need different guide than this one. • If you are building a road-worthy, use-it anytime, no excuse EV, it

needs to be, reliable and safe everyday, then this is your guide. Motor curves: What they mean & What assumptions you can make Every motor manufacture will provide motor performance curves. These curves tell some of the story, but not necessarily all. Different companies use different formats, but usually most of the information is there. Typically the curves will show at a given voltage, what the torque (ft-lb or Nm), motor speed (rpm), Amps, power output (hp or KW), and efficiency (% of power out to power in).

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Warp 9 @ 72 and 144 VDC

0.0

20.0

40.0

60.0

80.0

100.0

0 2000 4000 6000 8000

rpm

Torq

ue, N

-m,

Pow

er, k

W N-m @72N-m @144kW @72VDCkW @144VDC

Re-plot data at 72 VDC & 144 VDC see effect of voltage

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For you with English units preference,

Warp 9 @ 72 & 144 VDC

0.0

20.0

40.0

60.0

80.0

0 2000 4000 6000 8000

RPM

Torq

ue, f

t-lb

Pow

er, h

p ft-lb @72ft-lb @144hp @72VDChp @144VDC

Basically what happens is the higher voltage shifts the torque curve proportional to speed (this is approximate, not exact because of other factors). This increases the performance and power of the motor. The torque curve remains flatter for longer period or to higher rpm’s. This should greatly improve the driveability of the motor (this translates into less shifting of gears). However, more power output does generate more heat since you can operate at higher amps for longer periods of time. Nothing in life comes for free. Single ratio, Manual transmissions and clutches or Automatics The first question is should I use a single gear reduction, manual transmission with several gears, or can I use an automatic transmission? You can use all of the above, but with qualifications. Single ratio transmissions are used in several OEM EV applications; however they use AC induction motors or DC brushless motors. All of these motors are high rpm motors capable of 10,000 rpm or more. With 10,000 rpm’s to work with you can set the motor’s high speed to some reasonable top speed of the vehicle with a reasonable gear ratio. Since we are focused primarily on DC brushed motors, they are limited to about 6,000 rpm. It is not reasonable to expect a gas engine vehicle with 6000 rpm rev limit to work effective with a single speed transmission and in fact we are seeing more and more gears to improve gas engine operating efficiency. Same holds for

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an electric motor, except the electric motor gets full torque at zero rpm, rather than out near the rev limit. Some people don’t realize the excessive strain that trying to run with a single ratio puts on a DC motor and controller. The issue is complex because the single ratio requires a low (numerical number) ratio, say 5:1. In a typical passenger car, this would equate to 60-80 mph at 5000-6000 rpm (maybe 3rd gear). This would make launch from a stop and acceleration up in speed require a lot of torque and amps to happen. You would find that you quickly heat the motor and controller up with the continuous high amps under high load. This is the important point – heat – without the ability to change ratios you will find that both the motor and controller will be at it limits in certain conditions. One of the early questions was what are your expectations for gradability? What kind of grades, at what speeds, for what distance or time do you expect your EV conversion to handle without over heating and shutting down? If you analyze this, I think you will see that multiple gear ratios is the best way to deal with this. Also most motors have efficiency curves and there are motor speeds and torques that are most efficient. With multiple gear ratios, you can optimize your operating point for maximum efficiency. I hope this will help some of you from going down a road fraught with overheated motors and controllers. When in doubt, keep that transmission in the loop. What about the clutch? This depends on how you are going to drive your EV. First of all you don’t need a foot operated clutch. Unlike your gas car, when you come to a stop in an EV, the motor also stops. When you start, you just step on the throttle and take off, no need to slip the clutch out so as to not stall the gas motor. When it comes time to shift, you just shift gently up in gear ratio. Going up in gears is not hard on the transmission because you are shifting into a slower set of gear speeds. Down shifting can also be done without a clutch, except if you are trying to do it fast and hard. The transmission has synchronizers and if you pull gently and firmly and let the synchronizers do their work, clutchless shifting works well. The major issue with a clutch is exciting a series DC motor without load on it (as in putting in the clutch and revving the motor). DON’T DO THIS!! A series DC motor will go unstable and start to spin out of control, even after you release the throttle (basically the armature circuit includes the resistance of the field winding and the speed becomes roughly inversely proportional to the current. If the load falls to a low value the speed increases dramatically, which may be hazardous.) You have to put a load back on quickly (release the clutch) before things get out of control. Automatic transmissions can be used but have significant limitations. They have a fluid clutch (torque converter) that basically under a 1000 rpm’s just spins and does not transfer torque. So with an automatic transmission, you

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have lost the use of the initial start-up torque and have just been spinning the torque converter. Automatic transmissions are heavier, too. And as far as shifting, the automatic transmission needs to be recalibrated since the behavior of an electric motor is very different than a gas engine. Bottom-line, it has been done and it does work, but it is less efficient and requires more tinkering around. Some people will tell you, you can eliminate the torque converter and connect the motor directly to the automatic transmission and let the hydraulics of the automatic transmission do the shifting for you. This should work but you have loss the torque converter multiplier effect, which may not be as important with an electric drive. But automatic transmission will shift through all the gears, which you may not need or want. There is a lot of calibration work to make it feel right. Mounting the motor to the transmission This is a very critical element of the conversion. It needs to be done correctly or the problems can be severe. Basically you have a transmission that expects to be mounted to an engine block with a set of specific mounting holes. The transmission expects the clutch and flywheel to be in the proper position. There are several companies out there that make these adaptors. I recommend visiting www.ElectroAuto.com and read about their adaptors for various motors and transmissions. They understand the issues and offer a well designed and made assembly. I used one by ElectroAuto on my Cavalier conversion in Chapter 9. When mounting the motor to the manual transmission, you may ask why do I need a clutch? Actually, you don’t. This begs the next question, Do I need a clutch pedal? And again, you don’t. But there is not consensus on the right way to do this. I like the idea of a lightweight flywheel with the clutch plate. The clutch plate offers the electric motor a “soft” connection to the transmission. The clutch can slip if the load is too high and it can provide a small level of isolation when shifting. The springs in the clutch plate also offer some shock isolation. The clutch pedal can go, unless you think it could be a “safety item”, such that if there was a run-away failure mode of the motor controller, you could put in the clutch to prevent the vehicle from moving while you shut everything down. This is probably not a good reason since you can use the vehicle brakes while you turn off the ignition switch as well. Mounting the motor/transmission assembly to the vehicle is the next issue. Motor mounts are covered in more detail in Chapter 9. The main issue is that you should be able to use or adapt the existing motor and transmission

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mounts. If you have left the transmission in its original location, its mounts should be fine. Transverse mounted motors are a little more complex since the electric motor is smaller than the ICE it is replacing and it does not have the mounting holes typical on an ICE block. However, the existing rubber mounts should be adaptable to the electric motor. You may need to modify the engine cross-member or build extensions to reach the motor mount attaching holes. The original mounts were designed to take the many different types of loadings engines are subjected to. These include wide-open throttle accelerations, rock cycles (shifting transmission back and forth from forward to reverse as you try to rock the vehicle out of snow or mud), rough road vibration & durability, crashworthiness integrity, and general road durability. So if you can take advantage of all of this work and validation, you are ahead of the curve. You can build your own system but be careful since you will not be able to “test” it for long term reliability. Some motor issues to have you consider. I have used a Warp 9 motor in my Cavalier conversion (Chapter 9). These motors are very robust and have dual sets of brushes for long life and high performance. The motors also have an internal fan that not only helps to dissipate motor heat but also clears out carbon dust from the bushes, thus preventing a flash-over that could cause damage. The motors have a couple of items that are nice features that you can used to improve life and carefree operation.

• Warp motors have an internal thermal switch on the side that snaps open (normally closed) when the internal motor temperature reaches a high level (120oC) where you are endanger of burning out your motor. The switch can be used for several things. You could wire your contactor signal through this switch so that when the motor gets too hot, the thermal switch opens which in turn opens the contactor and the motor no longer can continue to run. Another use can be to turn on a warning light on the dash, that tells you the motor is hot, slow down and let it cool off. There may be options to use this signal to send a message to the controller to reduce motor current, in order to let the motor cool off.

• Warp motors have added a brush wear sensor which once the brushes

have worn down there is a contact made to close a circuit that could be used to turn on a “Service Soon” or “Brush Wear” light on the dash.

Most DC motors used in Electric Vehicle conversions are open frame with vents for air to enter and exit and for access to replace brushes. How does this open frame work in an on road EV Conversion and will there be problems with water and dirt? This answer is one of trade-offs. First the motors are forced air cooled; not sealed and water cooled, so it must be

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open. OEM’s usually use sealed water cooled motors, so they don’t have this problem. I have seen pictures of simple DC motors used in a farm application totally covered in mud and still operating! These are not high performance applications so do not let this happen in your conversion EV, just understand that DC motors are very robust. Relative to Motor Care and Maintenance:

• Protection from the elements is important. Utilize good design concepts and materials to protect the motor from rain, snow, and ice

• Design the motor mounting area to allow for good air flow. The motor

needs a continuous supply of clean fresh air to cool properly

• Protect the motor from “dirty air” that may be used to cool it. Most airborne grit will act as an abrasive, which will eventually cause harm to the internal part of your motor. Dirty motors run hot when thick dirt insulates the frame and clogged passages reduce cooling air flow. Heat reduces insulation life and eventually can cause motor failure

• Clean the brushes and commutator regularly from the dust/dirt that

occurs during normal operation. Do not use high pressure air to blow this dirt out, you will only force dirt into the wrong areas and potentially cause other problems

• Regularly check connections, voltages, tolerances and alignment to

assure they are within normal specifications. If you hear noises from the motor during operation, check this out further. Sometimes just jacking the drive wheels off the ground and letting the motor turn over slowly and listen for unusual noises can suggest the need for more thorough maintenance and inspection

• Always operate the motor within normal safety ranges in voltage,

amperage and RPM • Follow all safety rules • Your motor will take care of you, if you take care of it.

NHRA (National Hot Rod Assoc) has rules for drag racing that says the motor needs a shield 360 degrees around to prevent parts and flames from shooting out if the motor explodes during a race. We don’t expect that problem ever to occur in our road car. But the design of a shield to keep the elements out and allow clean air in is important. See Chapter 9 for what was done on the Cavalier.

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What makes a quality motor:

1. High efficiency design using low-loss laminations and welded or fused commutator connections with a large commutator area. This helps to lower heat losses and yield longer operating times per battery charge. Efficiency should be reported on the motor curves

2. Durable construction where armature and field winds and assembly are treated to lock in mechanical integrity (such as using resin varnish) and provide permanent environmental protection

3. Quality parts and quality assembly means quality is controlled

throughout the manufacturing process and performance is confirmed with testing before shipment

4. High quality, large brushes (maybe even dual brushes), in strong

housings with heavy duty, vibration & corrosion resistant brush springs

5. Commutator construction that prevents lifting due to high

temperatures. The commutator is the major source for heat generation in a DC brushed motor

6. High temperature rating, no less than Class H for an EV application.

Heat is the enemy of all electric/electronic equipment. The table below summarizes common motor thermal ratings. The major concern is life of the windings and its insulation

Thermal ratings of insulation classes These are the highest allowable stator winding temperatures for long

insulation life. Temperatures are total, starting with a maximum ambient of 40° C

Insulation class Maximum winding temperature, C A B* F* H

105° 130° 155° 180°

* Most common classes for industrial-duty motors. 7. Balancing of the completed armature at assembly. This is important

for motors operating at higher rpms and can lead to much quieter and smoother operation in the vehicle

8. Sealed, high strength bearings with high temperature grease

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9. High efficiency fans that provide the necessary cooling with lowest

power requirements

10. Light weight or light as possible 11. Industry standard size mounting patterns and shaft ends 12. Ability to connect a speed sensor to the motor 13. Uses standard industry parts (like brushes) for service.

Is Regenerative braking possible with a DC Series motor? What is regenerative braking? Regenerative Braking or “regen” is a technology when you take your foot off the accelerator pedal to stop, that the motor becomes a generator and in generating electricity to charge your batteries, offers resistance in the drive system which results in some “braking-like” effort occurring. The generator converts kinetic energy of the moving vehicle back into electrical potential energy in the batteries. In a conventional vehicle, braking converts the kinetic energy of motion into heat energy in the brakes. Regen will supplement your brake system and slow your vehicle down and recharge your batteries. Regen can provide some range extension (10%) depending on how much braking you need to do and how much regen your system is set up to deliver. Regen is not well understood in the non-automotive world. Regen sounds/is great and can provide the effect of power brakes and deliver a more familiar slowing down when your foot is off the accelerator pedal. However, too much regen can cause serious handling and stability issues with a vehicle. Regen puts braking effort into the wheels that the motor is set up to drive. It a FWD vehicle, these are the front wheels and in a RWD vehicle, these are the rear wheels. On a road surface that is either slippery (snow, grass, or loose gravel or sand) or becomes slippery (first rain on the highway), too much regen will lock up those wheels from turning a cause a changes that are not expected. In a FWD vehicle, you can not steer the vehicle with the wheels locked and in a RWD vehicle you can lose stability of the rear end that will potential cause the rear end to loose control. Be careful with how you set regen, it can cause vehicle handling issues you never before experienced or expected. But can you put in regen? Quoting the words of Otmar Ebenhoech the designer and creator of the Zilla Controller from Café Electric: “In my experience braking with a DC motor in a full size EV just destroys the brushes and often destroys the commutator as well. This happens either in

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regen or plug braking. That is why I no longer make regen controllers. In my opinion the only real option for DC systems over 108V at this time is adding a generator/alternator on the end of the motor.” What he is referring to is the large inrush of current in regen back through the brushes and causing a lot of arcing, heat generation and destruction of your motor’s commutator. The concept of adding another motor/generator on the end of the motor has been done but offers some complexity in that you should have an electric clutch (like the compressor clutch on your ICE air conditioner unit) so that it can be decoupled (with a switch) when you do not need regen. If you truly want regen, than use a Separately Excited DC motor, AC induction motor or DC brushless motor with regen setup in their controllers.

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Chapter 6: Automotive Electrical Systems for EV Conversions The 12V side is covered in Chapter 7 on Original ICE Vehicle and Its Systems. I will cover some general issues that pertain to both low voltage and high voltage. First I want to cover the high voltage side. SAE recommends the all high voltage (>44V) wiring be orange in color with the high voltage ground return wires be orange with a black stripe. It is hard to find orange battery cabling in small quantities. You can find orange sleeving and I would recommend that if possible. As a last resort, use red color battery cables, but wrap orange tape at the end points so it is noticeable. Battery connection choices are many and each has pro’s and con’s. Many people use the standard lead clamp connectors with bolt-on battery terminal connections. Note: Positive and negative posts are different diameters to error-proof connections. Typical heavy duty Typical lead post battery Crimp/solder on battery crimp/solder battery connector for terminal end cable post connector cable connectors

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Insulated boots for protection For dual post batteries (stud for marine from high voltage and post for automotive (come in black and red) Deka battery with insulated covers & Radsok® Some words of caution: Lead is not a great electrical conductor which is why good quality terminal ends are plated copper. Also, you need to be sure you have a contact area both in the terminal and in the surface area being clamped down equal or greater than the cross sectional area of the cable. For example if you think you need 1/0 AWG cable, this has a cross sectional area of 83,000 circular mils or is 0.083 square inches. If you take a cross-section through the thinnest part of your connector, say it is ¾” wide, then the thickness must be at least 0.11 inches to achieve same area as the wire diameter. If you tighten it over a 3/8” stud (0.40” hole), then you need a good surface contact area of a little more than ½” diameter (0.51” diameter) to have the same area as the wire. If you do not have at least the same areas, you are losing the advantage of the wire gauge you selected. Sometimes this will show up as heat in your terminals. Be sure all contact surfaces are flat and clean. Clean is a major problem if you use flooded lead acid batteries, because when they gas and all of them do, there is a mist of sulfuric acid that is released, which is corrosive. Corrosion will reduce

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current flows by adding some resistance in all of your connections. How much? Depends on lots of things, but be sure to keep them clean. Now for my favorite connector; I have found a terminal end called a Radsok® that is produced by Amphenol and is a great solution, but don’t use these with flood batteries, because the sulfuric acid will destroy these over time. They work great with any sealed battery. Here is the website: http://www.amphenol-aerospace.com/new/radsok.asp?BU=2 I have used the 8mm Radsok® and it will carry 200A continuously, which is more than enough. The wire gage I selected was 2 AWG, which will carry 180A continuously.

Alternative insulating boot for a Radsok® Radsok®, plastic cover and pin The major advantage, in addition to the high current carrying capacity, is that all battery connections CAN BE MADE WITHOUT mechanical tools, which you can so easily drop and short out batteries. You can literally change your batteries out without any metal tools. (This is also an example of applying DFMEA – Design Failure Mode and Effects Analysis, to reduce the potential failure mode of shorting batteries or getting exposed to high voltage.) Just pull off the Radsoks® and remove the batteries. There are two varieties of Radsoks®. One is plain, which I have used without any problems (shown below), and the other is their SurLoc™ which is shown above and has a locking clip at the top. You will need to have a machine shop do your pin connectors to fit your battery studs. To keep height minimized, I actually cut a ¼” off my studs to lower the pin. Watch when machining the pins, Radsok® recommends a 30 micro-finish on the surface. If you want to do it right, have them machined out of copper and then get them flash silver plated. I have had no issues machining them out of brass with no plating.

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The next issue is crimping terminal ends. This is pretty standard procedure, but you need to understand that good crimps are not that easy to accomplish unless you have the proper tools. I recommend that all hand crimps be soldered for extra security (Please note that Radsok® will not tolerate the heat from soldering, so use only a high quality mechanical crimp.) For example, a proper (SAE defined) crimp on 16 AWG wire is for a pull out strength of 27 lbs. and for a 12 AWG wire it is 54 lbs. These are hard to do consistently and you don’t want bad crimps causing you phantom problems, or even worst is having a high voltage wire come off of its crimp and be lose somewhere. Obviously battery cables are similar. SAE defines for cables larger than 8 AWG, a minimum pull out strength of 135 lbs. Since the Radsoks® are now available with barrel crimps for standard wire gauges, you need a proper tool to do these crimps consistently. Here is a picture of a proper tool that has anvils/jaws for standard wire gauges. People have used the low cost, beat it with a hammer tool, but it is difficult to insure consistency and I would not recommend it. Some battery stores will make up cables and they use industry standard crimping tools, which is what you want. Here is a typical tool that I use. Battery cable crimper tool Radsok® & pin with crimp cable with insulator boot and water pass-thru seal

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Standard pin crimper for automotive Battery cable connectors & seals connectors like Amp Mate-N-Loc Insulate all your terminal ends to be sure no one is exposed to high voltage and to protect all your low voltage connections from shorting on something unintentionally. Again, there should be no exposed high voltage that could be touched without removing some bolted down or constrained cover. As a good practice, route your high voltage cables away from existing low voltage wiring. EMI (electro-magnetic interference) is reduced by keeping the high voltage wiring away from other 12V wiring. EMI is a whole other story, but do understand that we may have 50kW of power or more under the hood of the car. A 50kW radio station is a pretty powerful radio station and our wiring has similar potential to broadcast electro-magnetic energy which can cause safety issues as well as radio interference. The OEM’s go to unusual efforts to reduce EMI suspectability.

There will be a great deal of auxiliary connections to batteries – charger wires, sensor wires, DC-DC wires, PTC heaters, MDS, contactor, fusing, shunts, etc. All of these are high voltage connections and care should be taken to use proper precautions to insulate and prevent electrical shock.

General Issues: Tools needed Standard 6-in-1 tool, cuts, crimps, strips, Cable wire cutter cuts bolts, measures bolts & wire gages

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Multi-purpose linesman’s tool Automatic wire stripper – very handy You will need a soldering gun and rosin core solder (don’t use acid core solder.) You will need the usual assortment of needle nose pliers, regular pliers, wire cutters, and screw drivers. If you are taking apart automotive style connectors you need special tools that reach inside the connectors and release the pin that snap in place. Pin extractor tools When splicing connections use splice clip, then crimp and solder by applying heat at center and let solder flow in from ends both sides. Use good crimp tool with anvils for the various size wires you are using. Tape or put a piece of shrink wrap on a wire before you crimp. It is best to solder all hand crimp splices and terminals. Strip to ends of the two wires, insert into clip and crimp. Solder with heat at

center and flow solder from ends (best) or heat at center underneath hole and flow solder through wires

Or you can do it the harder way by

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Strip the two ends of the wires lay Twist from center to ends as shown

In all cases tape or use a piece of shrink wrap to cover completely Solder as shown Do not do splices without soldering. Do not use wire nuts, do not just twist wires together without soldering, and do not cover twisted together with tape to hold it together. These methods are not very reliable and will eventually give you trouble. Series hybrid generator for range extension Some people have done this and it is very workable. The issue is adding a generator (series hybrid) to charge the batteries while you are driving beyond the limits of the stored energy. How big a generator? If you are running at 300 Wh/mile at 60 mph, Then 300 Wh/mile * 60 mile/h = 18kW (18,000W). This says at 18kW you are drawing @144V, 125A.

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Chapter 7: Original ICE vehicle and its systems All right, you have a vehicle to convert to an EV; Congratulations! Now, what should you inspect, repair, fix, or save/discard for your “new” EV? Let’s start: Inspect/Repair/Fix/Save or Discard:

1. Manual transmission and clutch – all your power goes through the transmission to drive your wheels. At some point, after you have everything running electrically, have the transmission flushed and fill with a lighter weight oil (weight has to do with viscosity or thickness of the oil, the higher the number, the thicker.) Most people ignore their maintenance on their manual transmissions, but the gears do wear and sludge will build up and the shifting can get harder. Taking the drain plug out and looking at the magnetic pickup on the plug will show what is in your transmission. Normally manual transmissions use SAE 90W gear oil that is so thick it comes in squeezable containers to fill your transmissions. There are some lighter weight synthetic manual transmission lubricants. BMW and Acura use one in their transaxle applications. Redline Oil makes a product called MTL which is 70W80 GL-4 gear oil (SAE 5W30/10W30 engine oil viscosity) which is designed for use in manual transmissions and transaxles. I have not tried this but it “reads” very good. If you have a longitudinal mounted engine and have a rear differential, the same thing applies, find lower weight synthetic gear oil for rear differential.

2. Clutch plate – inspect and if it looks worn replace it. They are not very expensive and now is the easy time to replace it.

3. Flywheel – you will need this to mount to your electric motor. Flywheels are heavy to smooth out the gas engine through its firing pulses. You need very little flywheel, all you need is a clutch surface. The existing flywheel can be lightened significantly. You can take a light cut on the clutch surface to clean it up and smooth it out. Remove the ring gear for the starter motor – this is usually welded on or heat shrunk on. Either grind the welds off or cut across the gear and ring gear will fall off (as below.) I would not mess with the thickness from the engine crankshaft mounting surface to the clutch engagement surface. Changing this will require changes to the clutch throw out distance; which is only an issue if you retain the clutch pedal. Here is a picture before and after on a flywheel that was lightened significantly. Thickness was reduced from ¾” to 3/8” taking material off the back side. Be sure to balance the flywheel after lightening it. Doing this statically is good enough; you can read about how they balance model airplane propellers, and do it similarly.

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Before After

4. Half shafts (transverse front engine front wheel drive) or propeller (prop) shaft (longitudinal engine, rear wheel drive.) Make sure your half shaft boots are still in good condition and that the joints inside are sealed with clean and proper grease. If in doubt (lots of miles?) get new boots, clean out the old grease and re-grease with proper grease, and reinstalled the new boots. New half shafts can be expensive. If you have a prop shaft check out the U-joints on both ends. Make sure they rotate freely and apply grease to all the rotating parts. These are usually sealed for life, but new grease can’t hurt particularly if you can get to the bearings.

5. Frame or uni-body structure – look out for heavy rust; this can weaken the structure. When you get your donor vehicle check this out first. If you can get a relatively clean vehicle, that is a better starting point and will save you a lot of time with less prep work. Areas that show rust should be brushed, sanded, or sand blasted to clean and then repainted. Fenders or hoods can be replaced, but body side quarter panels are much more difficult to fix for heavy rust.

6. Suspension – These need to be in good working order. They control ride motion, rolling, steering, and braking.

a. Ride motion – This is normally shocks or struts. If worn, they can be replaced. Since the vehicle is going to be heavier at curb weight stiffer shocks are good to have.

b. Rolling – this has to do with wheel bearings. If they work smoothly and revolve freely, use them. Well worn in bearings are usually good, since they are “broken-in” and the seals are

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not as tight as new bearings, so they turn easier. If there is play (and there should be very little) (push and pull the tire assembly bolted to the hub at 12:00 and 6:00 o’clock) then you may need to adjust the bearings, if they are adjustable, or replace if they are unitized bearings (non-serviceable). You don’t want the bearings to have play in them because it can effect other issues like rolling, steering, tracking and braking.

c. Suspension alignment – is critical for low rolling resistance. When the vehicle is all put together and sits at expected curb weight, have the alignment checked. Toe is the most critical. Keep toe close to zero. Most vehicles have a little negative toe, which improves on-center feel going down the road, but with an EV you want to have as little rolling resistance as possible. Negative toe puts the tires pointing inward toward each other, so as you drive the tires scrub a little rolling down the road, a small amount of negative toe sometimes results in zero toe rolling down the road as the tires and front suspension geometry cause a slight deflection of the tires outward. You never want positive toe. Keep the caster to what the manufacturer recommends and set camber to zero to again keep the tires perpendicular to the road it is rolling on. If you hit a pot hole or a curb recheck toe because these occurrences can cause the toe to changing a lot. (You can check toe yourself with a helper by buying a piece of 1” aluminum tube, 8’ long that is straight and putting the tube horizontally on a block between the tube and the wheel at wheel center. Then using a square place a mark on

the ground below the outside of the tube against the wheel. Then go the end of the tube and do this again. Now go to the other side and repeat. Back the vehicle away and measure the distance cross-car to the marks at wheel center (A) and at the end of the 8

Front forward

A B

B<A = toe in; set close to 0”

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foot tube (B). If the measurements are the same, you have zero toe. If the front distance (B) is less than the distance at wheel center (A), you have negative toe. If you want to adjust, loosen the tie rods and screw them in or out to make the necessary adjustment. If your steering wheel is straight, then you must adjust the tie rods equally left and right to keep the wheel straight. Be careful, since some cars use left and right hand threads on opposite sides. (Mark everything with a Sharpie so you can always return to where you started and know what you have changed.) Go back and repeat the toe measuring procedure. d. Steering – take the tire assembly (at 9:00 and 3:00 o’clock) and

push and pull; if there is play your tie rod joints may need to be replaced. Also check to be sure the rack or integral steering gear is tight to its mounting. Be sure to hold steering wheel tight. Then there is the question of power steering. Do you have manual or power steering? Most vehicles today have power assisted steering to make it easier to steer, particularly when the vehicle is not moving as in parking. If you think you can live without power steering, try to get a manual rack for your vehicle. If your vehicle has hydraulic power steering (most commonly used system) then you have some options. 1.) You can buy an electric motor and tie the hydraulic power steering pump (take it off the gas engine you removed) to the motor. You can put this on a switch, so you can run it only when you need assist; this is a little weird and I would not recommend this in anything but a play-toy EV. 2.) You can buy an electro-hydraulic power steering pump that senses pressure in the lines and when required turns on an integral pump with electric motor. Several manufacturers have gone this route and you can find these pumps on eBay (Toyota MR2, Mazda 3, etc). 3.) Find an electric power steering (EPS) unit that will fit. More and more manufacturers are switching to EPS since it saves on gas consumption. In general option 1 consumes the most power and option 3 the least.

e. Braking – you want these to work well and not offer any drag. By drag I mean if you rotate the tire/wheel assembly, there should be no scraping or rubbing noises from the brake pads on the rotors; the wheel assembly should rotate freely. Most disc brakes have some drag because the caliper pistons behind the brake pads don’t retract fully after use, particularly as corrosion occurs and time passes. Clean all the parts, grease the caliper pins and any surfaces that rub against each other. For drum brakes, clean all the surfaces and lubricate all the pivot points and springs. Adjust the shoes so they release completely when

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pressure is released. Adjust and clean braking system so that it works and fully retracts when in the release position. Check the cables for corrosion because sometimes this will cause the parking brake to stick and drag.

f. Suspension arms, bushings and links – inspect, clean, paint over any corrosion. Rubber bushings should last forever, but check for cracks and chunks missing and if necessary replace them. Check for damage (bent arms should be replaced).

g. Stabilizer bars – check end links and bushings and stab bar mounting bushings. Replace anything that is worn out. Standard bar should be fine. If you change weight distribution or center of gravity height, you may want to change the diameter of the stabilizer bar. Too small or too large can create handling issues. Too small will allow more vehicle roll in turns and cause understeer (plowing into turns). Larger bars are typically available from lots of places. Be careful to not put larger bars in the rear without adjusting front roll stiffness at the same time. A too large a rear bar can cause oversteer and make the vehicle feel squirrelly (this is a scientific terms for tendency of the rear end to want to swap positions with the front end.) Changing to stiffer springs has a similar effect as adding a stiffer stabilizer bar particularly in turns.

7. Electrical system – Get a service manual and read through the electrical section. If you decide to use a SLI (standard starting-lighting-ignition) battery for your source for the 12(13.6) VDC operating system, then everything should be all set to hook up the battery, except you need a separate charger to plug in when you charge the EV batteries. If you add a 12V DC-DC converter to your battery pack to keep your SLI battery charged, then I ask why not eliminate the SLI battery and just use a DC-DC converter for your 13.6 volt source? If you decide to use a DC-DC converter, then hook up the positive output to where the SLI batter was connected (usually this is a lead from the SLI battery to the underhood fuse block.) There is more to understand than this. You need to match or control the 12V power requirements that your vehicle needs in order to size your SLI battery or your DC-DC converter properly. This is not that simple since many gas engine vehicles use alternators that can put out 100A or more. My 1997 Cavalier has an alternator with a rated output of 105A at 13.6 V or 1400W; the 2005 Cobalt which uses EPS has an alternator that is rated at 115-135A depending on which engine. We need to estimate the electrical parts power consumption and how will we control that power level to a manageable level. Automotive people talk about certain climate conditions that are worse case. Typically a

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dark cold rainy winter’s night is a high power consumption load. Here is a breakdown of those loads:

a. High beams – 65W x 2 = 130W b. Tail lights and park lamps – 8W x4 = 32W c. Side marker lamps & license plate lamps = 4W x 4 = 16W d. AC system is on and blower motor is on HI – 240W for blower,

the AC clutch is about 50W and AC condenser fan is about 250W. Since we have eliminated the AC system we only have to worry about the blower fan and the PTC heater element. This would be 240W for the blower motors (and 1500W for the PTC heater but the PTC runs directly off the batteries, and not off of 13.6VDC.)

e. Rear window defroster = 250W PULL THIS FUSE; it’s a luxury we can do without.

f. Windshield wipers will use 140 W in HI g. Instrument cluster with all of its lights – 2W X 5 =10W h. Body and engine controller module – 10W x 2 = 20W i. For a grand total of = 588W/13.6 = 43.2 A j. Your standard SLI batteries which are typically 45Ah for 20 hr

discharge, will last about 2 hrs at 14A; you are drawing considerably more in this situation. BEWARE!

k. You can simulate other more common driving situations and see how you are doing.

l. Don’t undersize your SLI battery or your DC-DC converter, in both case you will lose your 12V system, either with a dead battery or blow a fuse in your DC-DC.

m. Another recommendation to help manage your power consumption is to replace the blower motor speed control with a solid state controller (PWM (pulse width modulation) controller). The standard controller is a set of resistors in series with the motor and it gets hot and consumes energy. Secondly, I would replace all the major incandesant bulbs with LED’s bulbs since they are 1/10 power at the same or brighter illumination.

8. The grounding of the 12V electrical system is another topic, but I recommend not using the chassis for the ground on the vehicle’s chassis/frame/body/structure. I believe that the 12V system should be isolated from the chassis. For example, if there is a failure in the DC-DC, you do not want your EV battery voltage to show up on the frame. If you use one of your battery pack batteries as a 12V source and lay one of you battery connections to the metal floor, you have just shorted out your circuit and probably have a burnt ground wire some where in your car. How do I isolate the 12V system grounds? Depending on how old your donor vehicle is, you may have varying degrees of work to isolate the 12V system. Most vehicles in the last

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10 years have put ground wires on all electrical devices and have brought those grounds to collection points on the body/frame. There maybe a dozen of these collection points (see service manual). Take these collection points off the vehicle and put insulated splices to a new ground wire which you run to either your SLI battery or to the ground of the DC-DC. Do this for all the ground collection points. Now nothing is grounded to the vehicle’s chassis. Your “chassis ground” is now on your SLI battery or your DC-DC. This is identical to what was there originally except you don’t use the body structure as a ground path.

That concludes how to inspect and deal with your donor vehicle. Again, Safe is better than Sorry.

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Chapter 8: Conversion Process If you want to do it right you should have the following available to you:

1. Factory shop or service manual 2. Proper mechanical tools and equipment

a. Air tools like ½” impact wrench (sockets English & Metric), high speed grinder, cut-off tool, 3/8” air ratchet

b. Electric Sawzall reciprocating saw c. ½” drill (electric or air) and drill bits d. screwdrivers and wrenches e. hammers f. crow bars and pry tools g. Allen wrenches (English and metric) h. Torx sockets & wrenches (male and female)

3. Proper electrical tools a. Wire stripper b. Terminal crimper c. Larger crimper for battery cables d. Soldering iron and rosin core solder e. Volt amp meter

Nice to have tools:

1. milling machine 2. lathe 3. bandsaw (metal cutting) 4. bench grinder 5. sand blaster 6. MIG welder with enough power to do aluminum, too. 7. plasma cutter 8. hydraulic press 9. engine lift

10. transmission lift 11. cut off saw 12. air tools like an air saw, impact hammer, metal nibbler, sander,

etc. 13. low current meter 14. high voltage and current meter 15. You never have too many tools!

Process: You have done your advanced packaging work and know where everything will go, know what you need in terms of parts or systems, have ordered them and have them waiting for you to start. There is a sample Bill

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of Materials (BOM) as a guide in Appendix A. This is what I consider necessary to do an “OEM” like conversion. It is more than what is required to do a “hobbyist” conversion, but we want to tell how to do it right(safe) or better, not just do it.

1. Batteries – build the tray, the battery hold downs, ventilation system, covers as required, and all the cables to connect them together including your main contactor, Master Disconnect Switch, and controller fuse. If you use an E-Meter or similar device, you need a 500A shunt (or more if you need more amps than that)

2. Motor – have your adaptor plate and all of its parts to interface between your motor, transmission (gear box), your lightened flywheel and clutch plate. Build your motor mount(s). Just a quick word on motor mounts because I have seen this done poorly. The original car used rubber mounts to hold the engine in position both on the transmission and the engine. Unless you make all the mounts rigid (I don’t recommend this) don’t have some rigid and some in rubber, because you will cause undo stress on the rigid mounts and they will eventually fatigue and fail. I would recommend you mimic the original mounting system since it was purposefully designed to isolate motor vibrations, take engine torques and motor road induced vibrations. Follow your adaptor manufacturer’s directions precisely since they have done this before with other customers and they know what works and what doesn’t. This is a very critical component that needs to be done well, not just done quickly. All your motor torque goes through this adapter and it must be tight and remains tight “forever” as well as be perfectly aligned with your transmission input shaft. Most motors are air cooled with an internal fan. DC brushed motors are very robust and some water and dirt entry will not faze them a whole lot. If you want to put a shield in front of it, that is good and worth doing, just be sure you don’t block the all the air flow to the motor. Cooling is critical.

3. Controller – this component needs to be water proof, not just water resistant. The underhood environment gets very wet on a rainy wet roads or salty in colder climates where salt is used on the roads. Salt water can conduct electricity or current in certain conditions. This leakage current should not exceed 0.5 mA. You don’t want your controller to short out because of water entry. That can be dangerous and expensive! I know that the Zilla is not even water resistant and the Curtis controller is water resistant but not water proof. Both can have problems if they get very wet. Both have exposed high voltage contacts on the outside of the controller which must be fixed in your application. There shall not be exposed high voltage connectors, conductors, terminals, contact

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blocks or devices of any type that create the potential for people to be exposed to 50 volts or greater. This means you need to put these devices in a sealed container that requires some specific action to access. All the signal wiring to these devices should go through a connector in the side wall of the container. These connectors should be water sealed as well. Many people use potentiometers for the throttle sensing. These are crude, will not meet SAE requirements and are not as robust as the many available electronic throttles used in many automobiles today. Throttle by wire is becoming more and more common. These pedals are tested to millions of cycles, are totally sealed, and have redundancy built into the electronics. Both Curtis and Zilla have options for electronic throttles. Take advantage and use these, the pricing has come down tremendously as these are being made by the millions, today.

4. Charger mounting, battery connections, and the charge port for plugging into the wall. Most chargers generate heat when they are operating. Place the charger so that it can naturally cool itself. Again, all connections to the charger and batteries should not expose people to high voltage. Good chargers have sealed connections to the charger. The charge port and charger should similarly not expose people to high voltage AC from the wall outlet (this would typically be 120 or 240 VAC.) The charge port should be located where it is convenient to use. Some chargers or controllers sense when the charger is plugged into the wall and will not let the electrical system activate when plugged in. This is a good safety feature to have. If your charger can plug into a number of different wall sockets, you should make up adaptor cables to allow you to plug into as many as possible. When you need a charge, you need a charge and don’t need excuses about not being able to find a compatible outlet.

5. Electrical low and high voltage wiring must be done carefully and correctly to insure reliability and safety from high voltage. Layout a wiring schematic with all the features and components for both low and high voltage.

6. Mount all of your accessories for your EV and then connect them according to your schematic . Check and double check all your wires and their routings.

7. Drive system 1st test. First are the batteries charged and ready to go? Second, make sure the drive wheels are jack up off the ground. Are critical support systems operational? If the controller is water cooled, is the system filled and is the pump working. Check your lights to be sure they are working, the brake lights, turn signals, headlights, and tail lights. Make sure your MDS is ON.

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Turn the ignition switch ON to activate the main contactor. When it fires you should have power to your controller and motor. Gently press the accelerator pedal and the motor should start to turn. Be careful to not excite the motor without a load on it, or the motor speed can start to run away. Be prepared to push the brake pedal if this happens. If everything is working properly then only some tweaking is needed. If your controller is programmable, hook up your laptop and read all the parameters settings. Change those that best suit your vehicle. If the motor does not turn over, you need to determine why and correct it. Is the contactor firing? Is the throttle controlling the speed of the motor? Does your controller record and save trouble codes that you can look up? If all is ok thus far, I suggest having someone new check the wiring and make sure everything you thought you did right was done right. Fresh eyes are a great resource since you are so familiar with it, you might not be seeing what you actually did versus what you planned to do.

8. Now take your vehicle out for its first test drive. Create a log of miles at start and miles at end and Wh’s used. It is nice to have a meter that will measure amps and Wh out of the wall and into the batteries. Run the vehicle through its gears and decide which gears work best for the vehicle operation. Typically, second gear and fourth are all you probably need. As you climb hills, you may want to use other gears. Using the tach and amps being pulled by the motor, you will start to get a feeling of where the motor operates most efficiently. Run the vehicle for 15 minutes, stop and take a temperature measurement device like an infrared thermal sensing gun. Read the motor temperature, the controller temperature and any thing that appears to be hot. Sometimes poorly made battery connections will get hot and these need to be fixed to reduce resistance in the connection. If you get more confidence about the running of the vehicle, start to run for the range limits. How far will it go at 35, 45, 55, 65 mph? Time the vehicle from zero to 60 mph; does it meet your projections. Find some hills and start climbing them and watch your amps. Periodically if you are drawing high amps, stop and measure temperatures as above. Check your brakes and steering a make sure they are working properly. Check your tires to make sure they are properly filled to the highest pressure on the sidewall.

9. If you have new batteries, they will need to be cycled deeply maybe 20 times to complete the battery formation process. As this is done, the batteries get stronger and hold more energy and you will go further.

10. You are now ready to tour the Galaxy in your EV conversion.

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Chapter 9: Example of an “OEM-grade” conversion

This project started with a 1997 Chevrolet Cavalier. The car was found on the street with a for sale sign for $500. The engine had a thrown a connecting rod through the block. We offered $400 and he took it. We paid a friend another $400 to pick it up and remove the gas engine, exhaust, fuel system, radiators and condensers. He kept those parts for fixing up other cars he repaired. We took the clutch, flywheel, and the motor mount and torque strut and hydraulic power steering system.

$400 donor car w/ blown engine – 160k miles Rear View

Interior view Complete Engine Compartment

Engine Block with couple through holes Manual Transmission without Engine

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I did a complete weight and balance on the vehicle (actually I did this before I bought the Cavalier to be sure it would make a good conversion.) To do this safely, one must try to get the completed conversion car with passengers and luggage at gas engine car’s rated GVW (Gross Vehicle Weight) and not to exceed either the GVWF or GVWR (Grosse Vehicle Weight Front or Rear axle.) One should attempt to keep the weight distribution front to rear similar to original or closer to ideal 50%/50% weight distribution. Many passenger cars, both front wheel drive (FWD) with transverse engine or rear wheel drive (RWD) with longitudinal engine end up with heavy front weight bias around 60/40 (front/rear). There is little the manufacturers can do to alter this although most would like less weight on front axle. Many manufacturers will add aluminum parts to the front end (engine blocks & heads, hoods, fenders, bumpers, and even aluminum front structure) and leave rear in steel. So here is what I did; get basic data on your ICE (Internal Combustion Engine) vehicle from data readily available on the Internet. Curb weight, GVW, wheelbase, weight distribution at front and rear axles. You can even find a similar car on a used car lot and open the driver’s door and look on the door and you should see a label with GVW and GVWF & R. You then need to estimate weights for the major parts being removed and EV parts going back in. You can find weights for most of your EV parts on manufacturer’s websites and retail seller’s of these parts. Here is a quick weight estimate and then a weight and balance on my 97 Cavalier to illustrate the process and help you understand how to set this up. Vehicle Weight Analysis - voltage to 144VDC 1997 Cavalier RS 2-door

Cavalier Standard M/T weight as received

LF RF Front 798 898 1696 64% LR RR Rear 539 406 945 36%

Total 2641 System in Vehicle Item wt, lb Total vehicle GVW, GM defined

on door label 3600 defined 5 passengers 840 calculated luggage (GVW-

passenger-curb below) 119 calculated

max curb based on GVW 2641

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est curb w/ AC based on car as weighed

2641

weighed

Vehicle Sys Item wt, lb.

HVAC A/C Body remove rr ctr belts 1.1 estimated Engine/ Transmission

Engine/Trans -MT with shift controls

600.0 estimated

5sp M/T back in -170.0 estimated Fuel & Exhaust Fuel & exhaust 120.0 estimated

Fuel Fuel, 14.1 gal 86 calculated Jack delete spare tire,

tools & jack 38.0 estimated

Electrical eng harness + battery

50 estimated

Radiator/Grill radiator 40 estimated misc removed -

heat shields, power steering lines, PS pump&brkt, fuel lines, HVAC-evap & heater core (includ'd in above), air bags

40 estimated

Engine/ Transmission

coolant, eng/trans oil, misc

20 estimated

Weight Removed subtotal= 825.1

Vehicle ready for conversion

1815.9

delete 1 passenger

168

delete cargo capacity- no luggage

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EV conversion parts

Motor, Warp 9 156.0 spec Controller, Zilla +

hair ball + fuse + shunt + sealed box and wiring

38.0 spec & est

Zilla cooling sys, heat exchanger, resv, pump, DCAC inverter, hoses, coolant

7.0 estimated

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Charger(2) w/ DCDC

22.0 spec

charger plugs, socket, charge port

5.0 estimated

Batteries 12 - Deka 8G31

859.0 spec

High voltage wiring 15.9 estimated Body modifications

for batteries 40 estimated

Electronic Throttle-HEPI

1.0 estimated

Vacuum pump 2.9 spec hoses 2.0 estimated Electric power

steering (column & rack)

5.0 estimated

total add back EV Parts=

1153.8

Estimated New curb=

2969.7

Over original curb=

328.7

add 4 pass 672.0 add luggage 0.0 new GVW 3641.7 Over original

GVW= 41.7

Note: 42 lbs is close enough that with carbon fiber hoods, fenders and deck lids, I could meet the GVW. Now the weight and balance to determine CG (center of gravity) for weight distribution calculation:

CG calculation:

wheelbase, in

104.1

Object weight, lb X, in wt*X, lb-in % front 64% as weighed % rear 36% as weighed front axle mass

1690 0 0 as weighed

rear axle mass

951 104.1 98974 as weighed

fuel tank batteries

357.9 78.5 28097 5 batteries

spare tire batteries

286.3 113.3 32443 4 batteries

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underhood 214.8 -18 -3866 3 batteries deleted items

remove rr ctr belts

-1.1 84 -92

Engine out -leave in MT with shift controls, clutch ped

-430.0 -6 2580 M/T back in

Fuel & exhaust

-120.0 72 -8640

Fuel, 15 gal -86.0 84 -7226 delete spare tire, tools & jack

-38.0 113 -4294

eng harness + battery

-50.0 -16.6 830

radiator -40.0 -23.5 940 coolant, eng/trans oil, misc

-20.0 -12 240

misc removal -40.0 50 -2000 added items Motor 156.0 -2 -312 FWD set-up Controller 39.0 5 195 Zilla cooling sys

7.0 7 49

Charger & port

27.0 125 3375 moved to rear

High voltage wiring

15.9 73 1164 more connections in rear

Body modifications for batteries, bat tray rear

20.0 80 1600 fuel tank area

bat tray mid 10.0 113 1130 rear spare bat tray frt 10.0 -20 -200 front rad area HEPI 1.0 vacuum pump

2.9 -16 -46

pump hoses 2.0 10 20 Master Disconnect switch + main contactor

7.0 93 651 put it in rear seat area

EPS 5.0 20 100

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charge cord reel

20.0 113 2260 not used but cord on reel in trunk

Totals= 2997.7 lbs 147972 cg: (inches

rear of front wheels) =

∑lb-in/total lb.

49.4

front weight= 1576.3 lbs %frt= 53% rear weight= 1421.4 lbs %rear= 47%

Since I am close to the original weights for GVW (over by only 42 lbs) and my weight distribution is better, my handling will be pretty good and over all safety should be good. Note that I have items that I could consider to get the 42 lbs out but the GVW for an automatic Cavalier is 3775 lbs, so I am within the validated weight limits for the car and chassis. Remember that GVM for a model line is curb weight, all standard options, all passengers, and all luggage. Options like automatic and sun roof add beyond what our vehicle was equipped with or spec’d out to be. Understanding these items helps a converter do a safe conversion within the limits the vehicle was designed for. One tool I use to estimate locations is to take a side view picture (off the Internet for example) and lay a grid over it based on knowing the wheelbase is 104.1.” With this grid, you can estimate where parts are and know the approximated distance from the front wheel. This model is where I ended, but it could be used early to start “playing” with battery locations and see where the weight distribution goes as you move them to different locations in the vehicle. Try to put batteries as central to the vehicle structure as possible.

(The battery of choice for my EcoVElectric LSV vehicle and for my Cavalier conversion was the Deka 8G31 gel cell sealed (maintenance-free) lead acid deep cycle marine battery. These are ideal for a standard highway capable EV. However, if you are building a dragster or a racer, you might want to consider a higher power battery. Deka’s can pull 550A CCA at 32oF and Optima D31A Yellow top spiral wound are capable of 900A. But if you want longest cycle life for standard EV, I would recommend the Deka’s in combination with the charger we will talk about shortly.)

The vehicle structure is designed to protect the passengers and if the batteries can be located in that same area, you will protect the batteries as well in an accident. For most compact cars, they use the area outside the car under the rear seat for the fuel tank; this is a good starting point. If you can or could get batteries into the tunnel where the exhaust system ran, use

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that too. This is an ideal place for batteries (it was too narrow and shallow in the Cavalier and I did not want to put the effort in to putting in my own tunnel and redoing all the interfaces of parts and systems to a new tunnel.) Then look at areas that typically do not crush much in an accident, like the spare tire wheel (throw out the spare, jack and tools and save - 40 lbs). Look at possible areas in the front engine compartment. The electric motor is much smaller than your ICE, particularly when you eliminate exhaust manifold and pipes, no accessory drive parts, like AC compressors and alternators, no radiators or condensers or fans. All these parts limit crushable space. As you put batteries in front, there are a few things to understand and avoid. If you look at the ICE version, you will note that there is a clear path with no non-crushable objects in front of the brake master cylinder (you can see this in the picture above.) In a severe accident (and they do happen) you do not want parts to get stacked up between the object being hit and the brake apply system. If parts do; they will push the brake system and steering column back into your face and possibly break your neck or give you a severe concussion or head injury. This is why there are crash standards that limit steering column rearward motion in crashes. (To make matters worse, with all our changes we decided to eliminate the air bags since we have done so many things that might effect the crash pulse, but if you wear your seat belts and sit at a proper distance from the steering wheel, air bags offer minimal additional safety improvement.) Keep your batteries as low as possible, but not so low that they are the first thing that hits if the car bottoms out or you run over something that might catch the pack. You can add protector skids if you are concerned it might pick something up. If you do a pickup, I would avoid putting all the batteries in the pickup bed, since that will raise the center of gravity (CG) significantly and may affect handling of the truck. Putting them down lower between the frame rails and outboard of the frame rails helps keep the CG down. Be careful where you put things. Some of this is covered in other sections of the Guide, so go back and read them again. Again these are guidelines, so if you don’t follow them you will at least be aware of the potential consequences. Do It Right, Do It Safe; that is my recommendation. So let’s get to work now that there is a plan for building the EV conversion. Let’s start with the rear battery positioning and mounting. We started with building a mockup size battery out of Styrofoam since it is lot easier to move around. We see how the four batteries position and what modifications are needed. First picture shows how the forward corners of the tub are cut out and how the rear area is removed to allow all four

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batteries to be positioned. Then we construct the battery support structure from aluminum angle. The parts are pop riveted together and bolted to the spare tire well. The four batteries are placed in location and two support/retainer pieces are made out of wood using threaded rod to hold the batteries from moving or falling out in a roll-over or crash. We will later make a plastic cover so as to seal the outside of the car from the inside. This open structure will naturally let the batteries cool if they get hot.

Lightweight Styrofoam mock-up battery Cut the tub Build the battery support frame 4 rear batteries sitting on tray Next area is the fuel tank area. We use our mock up battery to mark the five battery positions. We cut the rear seat floor out. Since seat belts attach to this structure and have weaken it by removing a lot of it as well as weakened the structure, we will add structure back in by welding a steel tube across the underbody and attach it to the rear longitudinal rails on both sides. Then we tack weld the floor structure to the tube to hold everything together. The battery supports are made and pop riveted & bolted together. Vertical supports are tied into the newly welded in cross car brace and to the forward part of the floor. There is actually a box section in the floor in this

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area. We position the vertical height carefully since we have ground clearance concerns from the bottom and seat position height from the top. We know because of the height of the batteries, seating position will not be as good as the original car but adequate. Again we make battery hold pieces from plywood and bolted and secure the batteries. Later we will finish the top cover and rear seat cushion. Mark and cut the rear seat pnl Build the frame to hold batteries Note we have removed the center seat belts and will eliminate center rear seat position and gain 170 lbs we can use in meeting GVW limits. In the front we need only to locate 3 batteries. We place these with understanding of crash considerations as seen below. We build supports from the same aluminum angle and pop rivet and bolt together. Batteries are placed on top and again plywood hold-downs are used to secure in place. We use the strength of the radiator support cross-member to carry most of the battery weight. Next is the motor. I used a NetGain Technologies - Warp 9 motor which is a very well made dual brushed series DC motor and will run it at 144 VDC. (www.go-ev.com ) The curves shown in the motor section will give you an idea of the performance expectations. Mounting the motor to the transmission needs to be done right and I recommend a company like Electro Automotive (www.electroauto.com) who uses a taper lock hub adapter to tie the flywheel to the motor output shaft. There are other good companies that do these adapters too. This is important if you want to keep things tight and never have to worry about it. Read their words on their website for more information. Many people do it the easy way with set screws and this may work for a while, but can eventually give you problems. Taper locks are often used in critical industrial applications and are very secure. Electro Automotive carries an inventory of standard patterns for many different transmissions. When using the tapered lock, follow the

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instructions carefully and it should stay tight forever. A set screw hub lock can loosen over time causing the lost of the clutch pressure or rattling inside the transmission and/or damage the transmission’s seals. The adaptor plate has a spacer ring that put the motor in the right position for the transmission and clutch. Assembly goes like this: Loosely assembly the hub to motor shaft, attach the spacer ring to the motor, attach adapter plate to spacer ring, slide the adaptor hub in and out to get the critical distance with flywheel loosely attached (this distance is critical and measures how much the flywheel mounting surface is inside the transmission case. It is easiest to measure when the flywheel is still attached to the crankshaft – measure the distance from rear face of engine block to the clutch surface on the flywheel. Now slide the hub adaptor measuring from the mounting surface on the adaptor plate the same flywheel clutch surface. Carefully take off the flywheel and start tightening the tapered lock. Your may need to do this a couple times to get it right. When right, tighten down the tapered lock hub. Install flywheel and tighten and install the clutch plate housing and tighten. Now you should be able to install the motor to the transmission using an engine lift or shop crane. My adaptor plate had a small problem in that the inner drive axle joint did not clear the adaptor plate. I marked this interference and after a couple tries, I cut off the interference and it cleared and slipped on the transmission shaft. Motor with adaptor plate and spacer Taper lock hub fitting for flywheel & clutch plate to mount to motor shaft

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Lightened flywheel to attach to taper Clutch assembly with plate inside lock motor shaft fitting to attach to flywheel Ready for hub fitting and clutch/flywheel (Note on bolts. Most cars in America since the 1970’s have Metric bolts but some still retain English fasteners. There is a chart at: http://www.boltdepot.com/fastener-information/Materials-and-Grades/Bolt-Grade-Chart.aspx which shows the specific markings for the different grades of fasteners. Each bolt has a specific marking indicating the strength required in that application. High strength fasteners allow more torque and tightening power than lower grade fasteners. Always use the same grade fastener or higher. In any structural application avoid standard off the shelf bolts and nuts which typically do not have any head markings on them and are typically Grade 2 material. These are good for your backyard swing sets but not for any high load automotive applications. (If you try to torque to manufacturer’s recommended torques you will twist them apart.)

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Motor mounts are another challenge. I used the existing transmissions mounts as is. There are two on the transmission, one forward side and one on rearward side. The engine mount on the original motor was designed to provide good isolation and control of the motor under torque. I believe it is worth while trying to use these. An electric motor does not need as much isolation as an ICE but that should not create any real problems in a conversion. With the motor attached to transmission and being supported by the shop crane, I laid out and built a cardboard mockup to check out design #1 for fitment and location, “installed” it, found some issues, changed it, tried a new a version, and was satisfied. It was designed to be made from standard steel flat stock. I laid out the pieces, cut them, tapped the top mounting piece to match the holes in the original ICE that were tapped, machined the precise hole pattern for the Warp 9 motor and welded it together. The entire mount piece also incorporated the original torque strut from the ICE. This is a very critical piece, particularly for a transverse mounted engine. The single mount on the motor side can not react very much torque which is why the strut was used. An electric motor will put out lots of torque fast and needs this torque strut to control motor motion. Engine mounting is a science in itself, particularly for transverse engines. Longitudinal engines are much simpler to do, but again I would recommend using the existing mounts where ever possible. All motor/transmission mounts are in rubber. Obviously a gas engine has inherent roughness from the fuel mixture exploding in the cylinders that an electric motor does not have. Don’t mount the electric motor without some rubber isolation. The rubber isolation allows the motor/transmission to share the support and reaction loads. Mounting solid will cause roughness as the 200 lb. weight tries to move around. Do not use some rubber mounts and some rigid mounts because you will fail by fatigue the rigid mounts after a while as it takes most of loads reacting the motion induced by the motor.

bottom view mount Fabricated motor mount bracket installed with torque strut with speed sensor & OEM mount

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motor mount from top/outside Motor mount from top/inside The last item to cover is mounting the speed sensor. Zilla wants industry standard 4 pulses per revolution speed sensor and Zolox is the recommended choice for the motor speed sensor (from EVSource). They are made to fit modern Advanced DC motors and Warp motors. The kit comes with magnet to mount to end of the motor shaft, sensor, mounting screws, and wire cable with waterproof connector. The issue is mounting it on the motor in the car. There are concerns that need to be recognized. The first is contamination and loss of the speed sensor function. The magnet picks up anything metal floating around it which can cause problems with sensing. Similarly, dirt, mud, water can cause issues too. There is a straight forward, easy way to install & protect the sensor, so you will never have to worry about it. Take a piece of tubing 1.5” diameter with .063” wall (1/16”) (16 gauge) & used this as the protective sleeve. The 1.5” fits into the motor end opening and the other end fits over the Zolox external ring (1.375” OD). The motor end gets a ring tack welded to provide a stop and to hold the sleeve in position when inserted into the motor end-cap hole. I made a simple aluminum plate to hold the speed sensor centered over a 1.5” hole. The key tricky part is to make spacers of the right length to hold the sensor at the right distance so that when the magnet is attached to the end of the motor shaft the speed sensor on its plate and the sleeve are in proper position. Pict of speed sensor kit Sleeve w/ sensor on plate at bottom

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Pict of assembly w/ mtr mnt tubes Same installed on mount (tubes to be welded Next step is to install the charger(s). I used two 72 V Delta-Q chargers with integral DC-DC converters.

Rear view of QuiQ-dci shows Panel Mount DC Connectors (48V output green [72V output is blue], 12V output black). Go to www.delta-q.com and read more about these chargers. They are available in the aftermarket. The chargers are totally environmentally sealed and electrically isolated. They are very sophisticated having a multi stage charge algorithm that starts with constant current bulk charging, then switching to a constant voltage, followed by an equalization low current charge. The chargers are very efficient and are air cooled. They are also available with a remote light to tell status of the recharging operation. The units have lights built in to tell status of the charger. The chargers are wired to allow a number of options including sensing when the charger is plugged

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in to prevent driving off with the charger plug in to the wall. The DC-DC can also be turned on/off with signals from the car. The chargers are 1kW chargers and can operate on either 120VAC, 15A standard wall outlet or 240 VAC (will draw less at higher voltage and will not charge any faster) automatically. Each charger will charge half of my 12 module battery string. One will charge batteries 1-6 and the other will charge batteries 7-12. The DC-DC converters are not isolated from each other and can not be used in parallel. They can be used on independent 13.6VDC electrical circuits in the vehicle as long as the grounds and 12+ are NOT shared with the other DC-DC. In the Cavalier, one DC-DC powers the car’s entire electrical system (with modifications, see discussion in previous chapters) except for the EPS. The other DC-DC will power the EPS (peak – 50A) and electric heated seats (Hi – 15A/pair) which are totally electrically separate from the vehicle’s main electrical system. The chargers come with a number of standard battery charge profiles including the Deka 8G31. These are selectable through the set-up procedures. The DC-DC is 30A 13.6VDC (400W) continuous and 60A for short bursts of < 3 seconds. It is internally fused and will shut down if overloaded and will automatically reset when back to normal loads appear. Please note that when you hook up the chargers to the batteries, the DC-DC is alive and generating 13.6 VDC on two of its output wires so don’t let these short out together or to the car. Tape them to isolate them until you get everything hooked up. I decided, for convenience to mount the two chargers in the trunk area. I did this so I could see the lights on the chargers. I learned about the remote lights after I had received the chargers and had originally planed to mount them underneath the floor where they are currently mounted. I only wanted one charge cord, so I wired the AC input cords together through an electrical box. My experience with these chargers is that they draw less than 10A max, so a 120VAC – 20A circuit should work adequately. The 120VAC - 20A plug is not as common as the 15A plug but they exist in many places and probably your garage in wired for 20A but only has a 15A outlet, this is easily changed but be sure it is on a 20A circuit breaker. The picture below shows the different outlets as well as the 15A – 250VAC and 50A – 240 VAC. 120VAC – 15/20A 250VAC – 50A 250VAC – 15A Dryer outlet

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The only issue I need to watch out for is the cooling for the chargers. These chargers naturally cool themselves with fresh air flow over the cooling fins on the sides of the chargers. If I find an issue, than I need to move cool air over the fins. This could be done with a small pair of 120VAC cooling fans. Pict of charger in back pict of charger Junction box Picture of charge port Overall view of charge sys pict of cord and adaptor to 20A 240VAC Pict of adaptor to 50A 240VAC These chargers are isolated from each other. However it is good practice to break your high voltage pack into 2 smaller packs. We installed our Master Disconnect Switch (MDS) at the middle of the pack. Both halves are 72VDC instead of one side being 144 VDC and the “other” side being 0 VDC. This

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offers potentially a little additional safety when doing service work. Besides that, this is also sensible, logical, and good place for the MDS. Here is a picture of the MDS box to be located in the middle rear seating position. In this example the MDS I choose was a Marine Blue Sea Systems switch. While it is only rated at 48VDC (because that is all they have tested it to and they do think it is capable of higher voltages but UL testing is expensive and this is all the boat industry needs), it is capable of accepting 1750A inrush, 350A continuous and looks like a “MDS.”

http://bluesea.com/category/1/products/9003e I use only one Main contactor located before the controller and it is an Albright SW-200

Albright model SW-200B SPNO Contactor with Magnetic Blowouts, 120 VDC, 250 amps continuous, 360 amps max, 12 VDC coil.

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These Curtis/Albright contactors use silver cadmium oxide contact material, which is able to withstand burning and is extremely resistant to welding. Magnetic blowouts allow rupturing of high currents at high voltage. The SW200 will handle up to 120 VDC, 250 amps continuous, 360 amps intermittent, and rupture 1500 amps. Here are pictures of installation of the MDS and Main Contactor in their sealed boxes (why sealed? How many times have you spilled your Coke/coffee in the back seat? You don’t want to short out your car or electrocute your passengers with such an accident.) The main contactor is in its own separate sealed box because in it located in the motor compartment and gets full exposure to outside climate conditions.

MDS in sealed box as seen when opened Master Disconnect Switch in box MDS switch installed in mid-pack Contactor box on front upper tie bar

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Main contactor in junction box Close up of sealed circular connector Lastly, let’s install the controller. I choose the Zilla 1K for several reasons. First and most importantly, the Zilla is programmable and you can do it. The Zilla also can output data on the system to a laptop computer and create diagnostic codes to help trouble shoot issues that may develop. The Zilla’s intelligence is well thought out and useful for road-worthy EV conversions. You can set voltage limits to protect your batteries and current limits to squeak out maximum efficiencies. You should buy it with the P-option that will accept an electronic accelerator pedal (highly recommend). It has a number of safety checks it can perform for additional safety, won’t start if foot on accelerator pedal or vehicle is plugged in for charging, etc. It will drive a tach off the motor speed sensor and send signals to your dash to turn lights on about battery voltage limits you set. It even has a “valet switch” to limit current when switch is closed (we will show you how we use it to create a highway efficiency limit current to maximize our range.) And Zilla promises there is more to come. Zilla is also water cooled which is probably more critical at 1000A than at 200A but that does add critical reliability to the electronics whose life is directly related to temperature (less heat is good!). But the Zilla was designed for “hobbyists,” not “automotive engineers.” As a result neither the Zilla nor the hairball are water sealed. Get them wet and you risk having serious problems (mostly expensive problems and I don’t know if there are potential safety issues that could occur, too.) But this is fixable. We recommend and used a standard plastic sealed enclosure box (I got on eBay) and mounted everything inside and used sealed connectors for all the wires and pipes going through the case. All the wires to the hairball are connected through a sealed circular multi-pin connector (there are many brands out there that do this, see Mouser Electronics Catalog for some.) All the battery cables go through sealed fittings to insure water tightness. Here are pictures of what was done. Inside the enclosure box is the Zilla, hairball, 500A current shunt for E-meter, prescaler for E-meter, 500A fast blow fuse,

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and the coolant pipes. The box is labeled “HIGH VOLTAGE” and can be locked to prevent accidental exposure to high voltage. The pictures below show what was done. The support for the Power Electronic Module (PEM) was a simple piece of aluminum tube mounted cross car to support it and a brace in the back to the dash panel to provide stiffness and stability.

Pict of box 14 x 12 x 6 Lower mounting plate with parts on it

Pass through front w/ circular connector Pass through rear w/pipes Zilla parts mounted inside ready for wires All wired up with e-meter voltage pre-scaler

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Supports to unit PEM unit from outside Cooling reservoir with pump inside Submersible pump inside I used the CafeElectric recommended pump which seemed reasonable ($) and low power. You do not want a high pressure pump. MAXI-JET 1200 is a submersible pump that is available at aquarium stores or on-line. It requires 120 VAC which is easily made with a simple 12V to 120 VAC inverter. The pump operates at 20W and provides 2.5 psi (less than 15 allowable) and a flow rate of 4.9 gpm (more than 2 gpm minimum.) UPDATE: http://manzanitamicro.com/ Is now building the Zilla Controller. CafeElectric is still around.

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Simple inverter to connect to 12V PEM Circular connector (not filled)

HEPI pedal installed with drip loop HEPI pedal installed HEPI is Hall Effect Pedal Input and is an electronic throttle and meets automotive industrial standards which mean they are sealed and contactorless and are tested for millions of life cycles. They will work worry-free forever if installed properly. No one should be using potentiometers anymore since they were a very crude “quick fix” created before the industry started to move to electronic pedals. Accelerator pedal-by-wire is now very common in modern automobiles and is the only way to go. The Zilla provided HEPI is good and comes with the cable and connector to the pedal. It must pass through the dash and you should use a tight fitting grommet to

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seal moisture out of the passenger compartment and prevent the sheet metal from cutting the cable where it passes through. Be sure to put a “drip loop” inside on the cable routing. This prevents water, should it get through the dash seals (and it will) from running down the cable and into the pedal connector and possibly getting inside and causing problems. The drip loop provides a low point where the drip will form and drop harmlessly to the floor. OEM’s use these often because they have been burned by warranty claims over and over with these potential leaks. My set-up parameters for the Zilla are contained in Appendix B. To extend range and be reasonable for a road car, I set max current limit to 350A. At 144VDC x 350A = 50kW or 68hp! This is more than enough. To achieve my goal of 200Wh/mile, the vehicle must be capable of running at 69A = (10000Wh/144V). UPDATE: There is a setting to cut off power if vehicle speed is zero. Don’t use this because the Zilla was not reading the speed signal and keep shutting off the controller at 10 mph. Changed this and Cav worked great. Other item is the HVAC which donated its heat exchanger for the Zilla. This unit was replaced with a PTC heater that will run on 144VDC (note use of high voltage orange power wires) and puts out 1500W of heat with the blower on HIGH. There are some pictures of what was done. Note: I live in Michigan and winters do get cold and this is an important feature both for safety (keeping windshield clear) and comfort. The HVAC unit was removed to install the PTC heater and this required the whole dash to be taken apart and removed. This was another immense task and I highly recommend using the Service Manual and take lots of pictures as you take it apart. Also label all the screws and where they go. As I took the unit apart, I also removed the evaporator and got rid of that extra weight, too. I sealed the holes for the tubing and hoses that enter the unit through the front of dash. PTC’s are nice in that they self-regulate. By this, they will change resistance to limit the maximum current or heat generated. The most heat is generated when the blower is on High and maximum heat is removed. To switch the PTC on or off, I used the AC switch on the HVAC control panel. You need to wire the heater so two items must be ON in order to send power to the PTC. The heater switch must be ON and the Blower/Fan control must be ON. The heater switch needs to go through a high current, high voltage relay. The nice result of doing this is that all the HVAC functions will work (except for AC) just as before, but remember this consumes a lot of energy and that is also range. Use it sparingly because you have no waste heat like your ICE and all the energy comes from your batteries.

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Pict of PTC heater installed Pict of PTC power relay outside Picture of HVAC unit in total from outside Control Pnl w/ mods for PWM UPDATE: We never got the heaters to work. It is probably a wiring error but time never allowed us to solve this. One item that I also changed to reduce my blower motor power needs was to add a simple solid state 12V PWM Motor controller for blower speed. This was a kit available on eBay (<$17) (www.electronic-light.com) and was installed into the circuit instead of using the multi-resistor element which generates a lot of heat/power except on HI. This is a significant power saver if you plan to use the blower and/or heater. It is capable of 20A which is just enough to cover the 18A or so that a blower motor needs. This pot mounts on HVAC control in place of the fan switch and the unit shown mounts remotely to it. Actual size is 2” x 2” x 1.5”

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The motor control 12V input & ground & motor outputs are here & are integrated into current wiring HVAC control panel PWM pot Rear View UPDATE: The PWM never worked so we bought an assembled PCM unit from eBay from China and adapted it. It works but speed control is really poor. Good idea just poorly executed. The other recommendation I have is to add electric heated seats (again easy to buy on eBay). Heated seats are not a “luxury item” in an electric car. They are actually very efficient both in power needs and heating your body. They typically draw about 40-70W each and all the heat goes into your butt and back relatively quickly. When installing be sure to put a power ON/OFF switch and relay that goes through your ignition ON/OFF switch for power. You don’t want to leave these ON when the vehicle is not being used. Pict electric heated seats pict of Heated Seat switch on dash Electric Power Steering (EPS) and its installation (OMG!). I believe that we will see more and more vehicles being equipped with EPS over the next 5 years rather than engine driven hydraulic power steering that has been standard for over 40 years. (Chrysler Corporation introduced the first

I used 2 sets switches. One turns the power to heated seats on and off. The other 2 control the power to each seat, both hi and low

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commercially available hydraulic power steering system on the 1951 Chrysler Imperial under the name Hydraguide.) EPS has the main advantage in that it only requires power when it is needed and only to the amount it is needed. EPS offers improved fuel economy by maybe 3-5%. It is much simpler to design into a vehicle and assemble at the factory. In lighter passenger cars it is done with an electric motor on the steering column shaft, see below. In larger cars the motor is being incorporated into the steering rack. Cav(below) vs Cobalt steering column Cobalt EPS(left) vs Cav Cobalt rack top – Cav rack bottom Note Cobalt vertical bolt vs Cav horizontal I used a 2006 Chevrolet Cobalt EPS system thinking it would naturally fit into its earlier brother the Cavalier. Pictures above show similarities but differences. EPS uses a manual type steering rack so you need to use the complete system. Again the parts were available on eBay and at reasonable prices. But having gone through this effort and tracked the time spent I would never, never, never do this again. I would recommend that you start either with a car with EPS (like Cobalt) or simply buy a used electro-hydraulic power steering pump, adapt this and use it. EHPS uses an electric motor and a pump that your hook into your existing power steering system. EHPS basically replaces your ICE driven power steering pump. I have not

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done this so I can not speak from experience, but in theory the pump/electric motor come on only when you need assist and the pressure drops. You can find these and other pumps on eBay or the Internet, including units designed for hot rods and custom cars. There are others that hook up electric motors to drive the original hydraulic pump but the mechanism to achieve high efficiency and power assist is difficult to do “production-like”. Putting a switch to turn the motor on/off when you want/do want assist is not production like. UPDATE: To get the unit to function we had to go to a salvage yard to buy the connector to the EPS unit. Our thought was to only apply the 12V signal required to recognize the vehicle had power on. The CAN signals were not available and we thought the default failure mode would be modest assist or even read the torque sensor and use that to assist the steering. In default failure mode, the assist is almost zero! EPS is totally worthless to assist when vehicle is still. We contacted the supplier of the unit but they were not interested in helping us with the default settings. The last chassis item is the electric vacuum pump. I choose one that MES makes that is quieter than many other brands. The vacuum pump is shown mounted in the old battery tray position and is connected to the original brake booster. The unit senses vacuum and only comes on when vacuum is needed. I have started without any additional reservoir. My HVAC unit also uses vacuum to actuate the various doors and flaps for the different selectable modes (and has its own small reservoir.) My thought is that the ICE did not need an extra reservoir and when the engine shuts off, so does the vacuum source. The boosters are normally sized to be able to provide a couple power assisted stops before all vacuum is lost. So will an additional reservoir save anything? We will test this out and see where we go, but you should not need one. 12VDC input power terminal (input from original battery) Original vacuum booster Original ABS module Vacuum pump 12VDC power ground (in place of battery’s chassis ground) MES vacuum pump

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Here are a few miscellaneous items. I disconnected (pulled the fuse) for the rear window defogger. This is a luxury item and we did without them for many, many years about 20 years ago. They would overload my DC-DC converter. Understand that the ICE vehicle has an engine driven alternator that is rated at about 125A. You don’t have that power available if you want any range at all. I also disconnected my Day Time Running Lamps, so that I use my head lights only when I want them ON. Again, an EV does not have any extra power to waste. Similarly, I changed out all my exterior lamps to LED’s to save 90% of the energy over incandescent bulbs. Unfortunately, head lamps are only now starting to switch to LED’s so the head lamps remained the same. High Intensity Discharge Lamps (HID) are used on the Toyota Prius because they require about 35% less energy, but they are very expensive (kits run around $400-$500.) Your choice, but I would expect the prices will continue to fall as more and more vehicles need the extra efficiency they provide. For instrumentation, I ordered a simple VDO tach that will work with the Zilla’s (and speed sensor’s) 4 pulse per revolution. I could not figure out how to use this signal as an input into the Cavalier’s engine controller which reads the engine crank sensor (7 pulses plus a check pulse per rev?) and sends signals that eventually get to the original tach. Here is a picture of installation. UPDATE: We either burned the Tach up or it did not recognize the Zilla’s signals? I also had an older E-Meter (now Xantrex Link 10) but needed a pre-scaler for the 144 V system. All the parts for operating and sensing were built into the PEM, so that is where the e-Meter is driven from. The meter is an ideal State of Charge instrument that can also show Battery Voltage and Battery Amps coming out of the battery. This is not quite true, since my DC-DC’s draw their power from my two “half packs.” Not all power being drawn from the batteries returns through the last battery ground at the Zilla where the shunt is located. The e-Meter can also track Ah, but this too is messed up by charging the two “half packs” separately and independently.

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E-Meter (old & used) Tachometer Lastly, I built my own battery voltage monitor. This allows me to monitor each battery, each half pack, and total pack voltage. It requires a 20 positions or so, rotary switch (double pole). I used a brass washer under each Radsok so by adding quick connect to the washer I could easily attach a lead. Then running a small gage sensing wire from each to my monitor, allows me to rotate the rotary switch to monitor the batteries. For the meter, I used a low cost, low end digital volt meter and directly wired it to the “common” position on the rotary switch (one pole is the positive side and the other is the negative side.) Battery voltage monitor Battery voltage monitor RearView pict of battery posts Pict of installation in glove box There is another critically important item is low rolling resistance tires (LRR). Through some investigation, I identified that the Cavalier uses the same size tire that the Honda Civic Hybrid uses and that this data was published on the Internet through the Transportation Research Board of the National

Under my Radsok was a brass washer with a spade connector. The leads from the voltage monitor connected to the spade connector

I just stuffed the whole unit into glove box with enough wire in the leads to be able to pull out and read.

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Academies. The report is not current accessible since there has been lot of controversy over tire rolling resistance as a piece of data that the public should have access to when purchasing tires and that the tire companies should provide. Rolling resistance is a key issue for EV’s. It was pointed out earlier in this guide, but what you want to be sure when you buy tires that the OEM’s claim to be low rolling resistance is that you get “OE tires” not just the same brand and size available in aftermarket stores. Ask for the “Article number” for the OE tire (and compare that to the standard tire’s “Article number” the store offers...it must be different because aftermarket tires are compounded differently than OE tires. It is impossible to get rolling resistance numbers from the tire companies. Only the OEM’s have this data, unfortunately. But this may change since LRR tires effects fuel economy and fuel economy affects our Nation’s dependence on Foreign Oil and the consumer should be able to buy LRR tires through competitive shopping. Low Rolling Resistance tires Tire on car Some updates. I had a short in the Engine Control Module, so I pulled the fuse to it. The only reason I wanted to keep it was to read the transmission speed sensor to drive the original speedometer. I will now add a simple speed sensor off the half shaft (like a bike or motorcycle speedo with a magnetic pickup.) a drive a LCD display. We had some problems with a short in the 12V system and found that one of the pins in the circular connector to the Zilla box was breaking intermittently. Fixed this and all should be good. And we are now done! OBSERVATIONS ANR SECOND THOUGHTS

1.) We killed the batteries because the engine control module had a short in it. We could not afford another set of batteries so we reused my EcoVElectric used batteries. We never really had the vehicle running properly because of the batteries, so we never were able to run performance tests.

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2.) We cut off the clutch pedal because an EV does not need a clutch. We use only 2nd and 4th gear to drive with. Up shifts are easy, but down shifts require a little care.

3.) If we had to do this all over again we would have replaced the 2 chargers with one 144VDC charger and similarly the 2 DC-DC converters in each charger with a single 144V DC-DC converter.

Tested results: Still TBD Weight at curb Weight at GVW 0-60 mph, seconds Range at constant: 35mph 45 mph 55 mph 65 mph Range around town driving (urban schedule based on real world?) Stored energy Maximum motor temperatures

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Chapter 10: Conclusions about Conversions My purpose is to show you how I would apply my guidelines to building a safe, reliable, roadworthy EV Conversion. The cost to do it like an OEM might do it is not significantly higher than what other converters are doing today. My purpose is to educate people interested in doing conversions on issues they are probably not aware of. Most “experts” in the EV Conversion business have been doing EV’s for many years. To do conversions safely requires more than experience, it takes knowledge and skills that these experts may not have been exposed to. “OEM automotive engineering” is not taught in schools or colleges. This knowledge is comes from working in the OEM’s organization and learning how it is done. None of the experts that I know actually worked in an OEM’s engineering department designing vehicles to be ready for production and worked on the OEM’s first production electric vehicles and conversion vehicles. EV Conversions can be done in many different ways. And many of these conversions work just fine within certain limits. Some are not driven in the rain. Some are not driven very much and some are driven a lot. For many hobbyists, the joy comes with fiddling with their cars. Some need to be very careful showing it at displays because there are high voltage safety hazards that could exposed unknowing people to shocks, if all the precautions of shutting things down were not completely done. These people feel really good about what they have accomplished and I respect that. What I want to do is to see EV Conversions start to appeal to the mainstream drivers, not just the EV enthusiast. I want to build and help other build “dumb-it-down” EV Conversions that anybody could use and operate safely. I don’t want to see cars that could electrocute someone if somebody forgot to do something to shut everything down. I have an EV and I drive it all the time. I stop and often get out to answer questions and forget to turn off the ignition because at rest an EV that is ON sounds no different than an EV that is OFF. If somebody or child climbs in, they can’t start it without being in the seat if you use a weight switch in the seat (a good idea). They can push the accelerator and nothing happens. This is error proofing which is critical in building safe and highly reliable EV’s or Conversions. In conclusion the Cav EV is an example of using my guidelines and providing the understanding why the things I do are better than some other choices out there and also providing the knowledge of the consequences of not following the guidelines.

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We in the World of EV’s do not want people getting hurt in their vehicles nor do we want to hurt others who are riding with us. It is not about doing it perfect, it is only about doing it the best we can with the knowledge we have. My hope is to get feedback from all who read this so we can continue to make the book better. I hope to share it with Electric Automobile Association to create a set of standards for converters. With a set of standards, we can move the EV conversion business forward with safety in mind.

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Chapter 11: Bibliography (Update- these worked in 2008 and may not in 2015!)

1. http://en.wikipedia.org/wiki/Main_Page I have used Wikipedia many times in many different places and highly recommend it as a good source of general knowledge.

2. http://www.go-ev.com This is the homepage for NetGain Technologies and was used to provide the Warp 9 motor curves.

3. http://www.eastpennbatteries.com/assets/base/0909.pdf Deka Dominator Gel Cell Battery from EastPenn Manufacturing Co. Inc. or http://www.dekabattery.com Same general site as above.

4. http://www.cafeelectric.com Home of the Zilla controller and direct access to Otmar Ebenhoech the owner and operator of the company. There is a great interview 3/26/2008 of Otmar on www.EVWorld.com but you need to be a subscriber is listen, which is something you ought to do anyway.

5. http://www.evparts.com Source of some of my pictures, my parts and where you can buy lots of parts and kits for EV’s (let the buyer be ware.)

6. http://www.evsource.com Another source for high performance and voltage EV parts for the conversion market. I used some of their pictures.

7. http://www.metricmind.com Source for high end AC drive systems and other assorted parts. Source for my vacuum pump

8. http://www.electroauto.com Home to ElectroAutomotive, my source for the adaptor plate. They sell many parts to build real world EV conversions.

9. http://www.ebay.com Where much (if not almost everything) can be found in your search of the Galaxy to save money, have fun and build your EV conversion.

10. http://www.waytekwire.com A great source for many of your electrical parts needs. They have just about everything to help put your EV together, wire, cables, terminals, boots, tools, etc.

11. http://www.mouser.com Home to Mouser Electronics and their 975,000 different parts.

12. http://www.mkbattery.com/techref_faq.php Home to MK Power and their solar power business and the link to a good

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technical reference to answer questions about the difference between Gels and AGM’s.

13. http://www.radsok.com/new/radsok.asp?BU=2 Radsok new homepage part of Amphenol Industrial Products, recommend you contact their offices in Fraser, MI.

14. http://avt.inel.gov/pdf/fsev/eva/99evatechspec.pdf This is the EVAmerica Technical Specifications document which I believe is the best document out there to do acceptable EV conversions for commercial sale. This is a good starting point and I have used a lot of this in my guidelines.

15. http://avt.inel.gov This is the home for Idaho National Labs and their Advanced Vehicle Testing activity. Lots of good information. You can read test reports on certain commercial conversions done over the last 10 years to help you set your objectives more realistically. You can compare what OEM’s and converters have done.

16. http://www.xantrex.com/web/id/10/type.asp Xantrex Link-10 battery monitor gage and their other products including User’s Manuals which have lots of good information about batteries.

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Chapter 12: Appendices

Appendix A - Bill of Materials

UPC Area Part Name Potential Supplier

Qty for Veh Weight, kg

Est-E

Wt-W

Part Description, material, process, alternatives

0 VEHICLE Complete ICE Vehicle 1997 Cavalier Cavalier take out engine 1 BODY

1A HVAC PTC @144 VDC EVParts 1 108-156 VDC 1500W PTC 1A heater on-off switch - with

light and on a timer?? need one 12V switch to high

voltage relay.

1A high voltage relay for heater EVSource 10A at 150VDC 1 deck lid, carbon fiber available but $550 to save 10 lbs

Body Subtotal= 2 Frame modified for Cobalt EPS Do difficult, would not

recommend Frame, Subtotal= 3 Frt Susp new higher load sprinjgs? 2 Not Reqd - close to original

GVW 3 Wheel bearings oK

Front Suspesnion, Subtotal= 4 Rear Susp new higher load sprinjgs? 2 Not Reqd - close to original

GVW Rear suspension and transaxle Subtotal= 5 Brake

a apply

Vacuum Pump for power brakes, 12V system

Metric Mind Engg Portland, OR 503-680-0026

1 1.3 70/6E MES vacuum pump; low noise with pressure sensor; 12V

5 frt drag free? Rotors & pads ok??

clean up and make sure they don't drag and do work easily

5 rear drag free? Drums and linings ok??

clean up and make sure they don't drag and do work easily

Brake System, Subtotal= 6 Prop sys Accel Pedal (electronic

throttle) CafeElectric 1 0.3 Hall sensor pedal - Zilla

6 9" NetGain WarP 9 EcoVElectric 1 70.9 off-the-shelf run at 144 VDC; at 89 VDC get 28 hp 1 hr rating; HP goes up with voltage

6 Speed sensor (Zolox) EV Source 1 Zilla recommended 6 motor mount, RHS fabricate to use existing motor

mount

6 Flywheel, mods local guy lighten,thin and balance Motor, Subtotal= 7 Trans std M/T with existing clutch 1 change if looks worn; looks good

7 Adaptor plate for motor to transmission

ElectroAuto 1 make high quality one - sent tracing of gear case

7 use standard drive axles 1 OK CVJ's and boots?; look good Trans Sutotal= 9 Strg System EPS power steering eBay Cobalt system - Ebay rack

9 column eBay Cobalt ebay

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9 Intermediate shaft eBay Cobalt ebay 9 new wheel, since Cav does

not fit eBay buy off eBay new wheel and hub

adaptor

Steering System, Subtotal= 10 Tire Whls Tires - 4 new Low Rolling

Resistance tires 4 195/65HR15 Bridgestone

Insignia SE200 (Honda Civic Hybrid uses same size); get OE tire through dealer (Article No. 072-497)

10 a Sealant, run-flat?? NO SPARE

4 TracNSeal Need something because no spare??

10 b mounting and balance Tires and Wheels, Subtotal= 11 Frt End Pnls

11 Hood, outer - Carbon Fiber eBay 1 Light weight part - assembly is about 15 lbs lighter but - $500

11 Hood, inner - Carbon Fiber eBay Light weight part 11 Fenders, light weight eBay 2 fiber glass or carbon fiber - but

$250 and maybe 5lbs lighter

Front End Panels, Subtotal= 13 Chas Elect

13 Propul Battery Management System 0 use DeltaQ control 13 Propul Battery interconnects-battery

to battery 24 machine Radsok pins, watch

surface finish

13 Propul Battery interconnect cables with Radsoks

24 13 cables with two Radsok per cable - Cable 2AWG

13 Propul Support, battery underbody rear seat area

1 5 batteries with upper cover

13 Propul Support, battery underbody rear trunk area

1 4 batteries in spare tire well w/ cover

13 Propul Support, battery rad crossmember

1 3 batteries

13 Propul Battery retention hrdw 12 fab something up 13A Propul DC Drive Zilla Z1K to 300V

with hairball CafeElectric 1 7.05 With -P option for HEPI

13 Propul water pump - for Zilla Maxijet 1200 powerhead - Marine Depot

1 0.2 Zilla recommneded pump

13 Propul water reservior fabricate to hold submersible pump

13 Propul interior heater exchanger remount under hood 13 Propul Charger (on-board type) for

144 VDC system Delta-Q 2 Could use new design with DC-

DC Std 72 V in parallel QuiQ 7212 charger with Deka algorithm

13 Propul Charger cord & reel (take with or leave at home)

Lowes/HomeDepot 1 20A 120VAC capable 10-3 x 50'

13 Propul Adpator plugs adaptor to 20A-240 & 30A-240 (dryer plug)

13 Propul Contactor-Main off battery with brkt

EVSource 1 Albright SW-200B w/ S&H

13 Propul Master disconnect Switch Go2Marine 1 Blue sea Systems 9003e 13 Propul Fuse F2 for controller

protection Fast react Café Electric 2 Ferraz-Swhawmut A30QS -

300V - 500A Part no. A30QS500-4

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13 Propul Connectors, High voltage upgrade to water proof

Radsok 24 Amphenol Radsok connectors with barrel crimps for 2 AWG - 8mm pin

13 Propul Radsok pins - ideal machine from copper and flash silver plate - but plain brass works, too. Ideal want 30 micro finish

see Radsok for dimensions on

8mm pins

12 & 12

Deka batteries need 5/16 threads for neg and 3/8 threads for positive; recommend cutting off 1/4" of stainless battery bolt to reduce overall height and use brass washer at bottom to get good solid contact with lead post.

13 Propul First Alert safety switch Ford car/trk 1 salvage yard part 13 Propul total length 2 AWG, ft,

orange? 40 2 AWG weldiing wire should be

ok for single wire 150A continuous; only RED available

13 Propul total length 2 AWG orange/black stripe

ft? didn't worry about this

13 Propul quant 2AWG 5/16 HD ring terminals?

Waytek 8 have extra just in case

13 Propul quant 2AWG 3/8 HD ring terminals

Waytek 12 have extra just in case

13 Propul Red insulating boots for batteries coonectors

Waytek 30

13 Misc ring terminals Waytek 10 13 Propul Battery - DEKA 8G31 Wronk in Warren 12 387.3 battery modules 12V 64.5Ah

C/1 10kWh nominally

Electrical, Chassis, Propulsion, Subtotal= 13 LowV Wiring Harness -

modifications - 12V 1 what gage, how much to

connect

13 IP Instrument Cluster 1 Need tach 13 IP small LED warning lights on

dash for battery low, Zilla fault, battery empty

Radioshack 6

13 IP tachometer to drive off Zilla 1 VDO 13 IP E-meter fuel gage Xantrex 1 already have 13 Front Turn Signal Lamp, pass

& driver eBay 2 LED's??

13 Side Lamps eBay 2 LED's?? 13 Rear tail lamps eBay 2 LED's?? 13 Rear third brake lights eBay 2 LED's??

Electrical, Chassis Low voltage 14 Bumpers, Jack, Tools

14 Bumper aero facia front (inclds sides and rear)

1 maybe later; improves aero(?) needs to be tested; adds weight

Bumpers, Subtotal= 15 Assy, Matl, total Vehicle

15 Factory shop manual eBay 1 Cavalier, used 15 Factory shop manual Helms 1 Cobalt 15 Chassis Alignment 1 15 Painting, re-paint white 1 go from black to light color to

reduce heat load in summer

15 Graphics 1 see what it takes to show it off

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15 labor, hrs direct & indirect Don't ask but a good estimate is about 500 hrs

Assembly & Paint, Subtotal= Total cost is quant x pc 467.03 kg Is not complete 1028.69 lb

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Appendix B – Zilla Set-up Configuration Main Menu d) Display Settings b) Battery Menu m) Motor Menu o) Options Menu p) Special Menu Esc) Cancel Battery Menu: Setting a) 350 BA Battery Amp Limit v) 124 LBV the Low Battey Voltage limit (80%DOD). The controller will automatically reduce current

so as not to run below this i) 144 LBVI Low Battery Voltage Indicator(60%DOD) - the battey light on dash will light below this

level Motor Menu Setting a) 350 Amp is the series or normal Amp limit for one motor v) 170 Volt is the series motor Voltage limit out of the controller i) 0 RA Reverse motor Amp Limit r) 0 RV Reverse motor Voltage limit c) 0 PA Parallel motor Amp limit p) 0 PV Parallel motor Voltage limit Speeed Menu Setting l) 5500 Norm is the forward rev limit r) 0 Rev is the reverse rev limit x) 6000 Max is the speed above which the Hairball will log an error Valet mode active or not: "State: 1311 Valet" is active "State: 1311" is NOT active Options Menu enter letter to change Setting

a) On Motspd1 On if using speed sensor mtr 1

b) Off Motspd2 On if using speed sensor mtr 2

c) Off AutoShift On enables auto shifting from series to parallel of two motor systems d) OFF Stall Detect On enables Stall Detect - lifting throttle resets - at high currents cuts off in

0.5 sec at low (50A) currents <12sec OFF if not reading speed sensor correctly.

e) Off Bat lt polarity change the output polarity of the indicator indicator light f) Off Ck eng lt pol change the output polarity of the indicator indicator light

g) Off FR Contactors Hairball wired for reverse contactors

h) Off SP Contactors Hairball wired for series/parallel contactors

i) Off Parallel Reverse

forces unit to stay in parallel when "h" is on and vehicle is in reverse; in some cases this can help traction

j) Off Drag race

k) Off Amps on Tach makes tach display motor amps multiplied by 10 instead of RPM

l) Off 6 cylinder tach changes the tach output from 4 to 6 cylinders when it is On

m) Off Plug in Polarity reverses the polarity of the Plug In Input

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n) On HEPI activates HEPI input, only used if Hairball is a -P model

o) Off --- not used p) On Z1K Scaling sets the amp dispay scaling to fit the Z1K instead of Z2K; turn this off for Z2Ks

Special Menu W) Reset

resets Hairball, this is for testiing, reloading code, and handy for reading the software version no.

c) Clear Error clears DTC error history

p) Precharge manually turns on the precharger for the controller, this is only for testing

Q) DAQ <1-

4> "Q" is data acquisition, this is how various data can be viewed in real time D) Defaults "D" resets all the values back to factory default values