kereta solar

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SMK TAMAN SERI KLUANG PREPARED BY; 1. NAVIN PUNJ A/L SHOMDUTT SHARMA 2. MUHAMMAD FAIQ FAKHRY B MUHD YAZID 3. LING JIA WEN ACCOMPANIED BY;

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Page 1: Kereta Solar

SMK TAMAN SERI KLUANG

PREPARED BY;

1. NAVIN PUNJ A/L SHOMDUTT SHARMA2. MUHAMMAD FAIQ FAKHRY B MUHD YAZID3. LING JIA WEN

ACCOMPANIED BY;

EN ONN AZRI BIN PUADE

TABLE OF CONTENT

Page 2: Kereta Solar

Content page

1. ABSTRACT 3

2. OBJECTIVES 7

3. SCIENTIFIC THEORIES 9

4. INNOVATIONS 12

5. FABRICATIONS 17

6. COSTS 19

7. TRIAL & ERROR 20

8. APPENDIX 21

1. ABSTRACT2

Page 3: Kereta Solar

1.1 OBJECTIVES

Nowadays, in the age of science and technology, the world

is facing the threat of global warming. Greenhouse gasses and

vehicle emission not only poison our air, but in the same time

causes the thinning of the ozone layer, up in the atmosphere. The

world today is indeed addicted to fossil fuels. These limited

resources need huge energy, and cost increasingly higher to

produce fuel. Fortunately, today, there are ‘green technologies’

that can help reduce and combat the effect of global warming.

One technology in particular is the solar technology. Solar is

the sun. Our closest star, which happens to be the center of our

solar system, emits radiations. Solar radiation is radiant energy

emitted by the sun, particularly electromagnetic energy. These can

be in a form of heat and light. The light can be generated into

electricity using solar panels.

Solar car has never been a hit, since it has always been

overshadowed by gas-guzzling vehicles. Fortunately, with

technology comes improvement. Solar panels today has come a

long way, enabling engineers and scientists to produce a more

stable and consistent current from each solar panels.

1.2 DESIGN INNOVATIONS

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These pictures are from later years of solar car race

competitions. As you can see, not that many schools really got the

concept right. As the name implies, a solar car is a type of

automobile, usually with 4 wheels and at least a seat for the driver

and more for the passengers.

This raises a question. Where is the driver’s seat?

Fortunately, with a little help from our teacher, we came up with a

design that incorporates user-friendliness.

Our solar car is designed with everything a car should have.

1.3 COST

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A simple formula in reducing cost ; mass production. The

most mass produced car, the Ford Model T is a brainchild of a

visionary, Mr. Henry Ford. He found out that early stages of car

development costs a lot of money. Then, he decided to mass

produce his car, reaching 1 million cars in only a few years. He

was successful and forever remembered as a automotive genius.

The early stage of our solar car involves building a prototype.

The main costs are material to build the body and researching for

the best possible combination of solar panel and motor. However,

there hasn’t been any monetary issue as we had full support from

our school.

1.4 MAXIMUM SPEED VS TIME OF DAY

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Page 6: Kereta Solar

After much discussing with our teachers, we came up with a

timetable, which we use to determine the maximum speed of our

solar car in relation with the time of day. We created a table which

we can monitor the results, thus improving the angle of our solar

panel.

Date \ Time 11.00 12.00 13.00 14.00

Date 1

Date 2

Date 3

Date 4

Date 5

Maximum speed (m/s)

The table above represents our trial in determining the

maximum speed in 4 different times in the afternoon/evening. At

first, we would like to do the test in 3 days, but the cloudy and rainy

weather makes our data hard to read. So, more data can lead to a

more grouped numbers and makes averaging the speed easier for

us.

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2. OBJECTIVE2.1 PURPOSE

The objective of this competition is to motivate Malaysian

secondary schools students in science, engineering, and

technology and to learn about solar power. Teams will design,

fund, build, and run a vehicle that is powered only by solar power.

Efficient balancing of power resources and power

consumption is the key to success during the race. At any moment

in time the optimal driving speed depends on the weather

(forecast). We were very fortunate to obtain the most efficient

balance in gear ratio and weight distribution. Our car can go quite

fast as we can get the right motor.

During the early stage of our R&D, we opted the use of a

regular DC motor. It turned out to be a high speed but low torque

motor. After discussing with our teachers, we changed the motor to

a higher torque and low speed motor. As a result, our solar car can

go at the slightest sunlight.

DC electric motor

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2.2 SPECIFIC OBJECTIVES

The main objective of any solar car manufacturer is to build

an efficient, "winning" vehicle. Design considerations included

hundreds of tradeoffs, but certain elements are essential.

Reliability is an important design factor. A vehicle which

performed well without any major breakdowns would cover the

race distance in less time.

The overall shape of a solar car is another important design

factor. Teams had to determine how and where they would mount

the solar cells for maximum energy grain. They also had to decide

how to maintain low weight and minimize aerodynamic drag.

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3. SCIENTIFIC THEORIES3.1 HOW DOES A SOLAR CELL WORKS?

A solar cell (also called photovoltaic cell or photoelectric cell)

is a solid state electrical device that converts the energy of sunlight

directly into electricity by the photovoltaic effect. Assemblies of

cells are used to make solar modules, also known as solar panels.

The energy generated from these solar modules, referred to as

solar power, is an example of solar energy.

Photovoltaic is the field of technology and research related to

the practical application of photovoltaic cells in producing electricity

from light, though it is often used specifically to refer to the

generation of electricity from sunlight.

Cells are described as photovoltaic cells when the light

source is not necessarily sunlight. These are used for detecting

light or other electromagnetic radiation near the visible range, for

example infrared detectors, or measurement of light intensity.

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Page 10: Kereta Solar

The solar cell works in three steps:

1. Photons in sunlight hit the solar panel and are absorbed by

semi conducting materials, such as silicon.

2. Electrons (negatively charged) are knocked loose from their

atoms, allowing them to flow through the material to produce

electricity. Due to the special composition of solar cells, the

electrons are only allowed to move in a single direction.

3. An array of solar cells converts solar energy into a usable

amount of direct current (DC) electricity.

4. The current produced turned the motor, which in turn drives

a set of gears to run the car.

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The power of our solar panel is;

*Tests are done under maximum sunlight;

Voltage = 2.5V

The current calculation must be done in a complete circuit,

since current doesn’t flow in a load-less circuit.

According to our experiment under maximum sunlight, the

current for our solar car is; 0.075A

P = I x V

2.5V x 0.075A

P = 0.1875W

= +- 0.2Watt

→P = 0.2W, lower than the 1W regulation.#

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V

Solar panel

Voltmeter

Sunlight

Current

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4. INNOVATIONS4.1 SOLAR CELL SELECTION

Our solar car project uses a common commercially available

solar panel, which retails at RM15.00. The low cost and high

efficiency solar cell is modified. We do without the panel holder,

which further lighten our final product.

The solar panel is efficient that we need only one unit to

power up our DC motor.

4.2 SOLAR CELL CIRCUIT

The solar panel, according to the shop salesman, are 2 solar

panel in a serial connection. Serial connection limits the voltage

output, but combines the current from each of the panel. As a

result, in theory the combined solar cell voltage output is only

about 3V, but the current can go as high as 0.1amp.

A famous misconception of voltage-current

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4.3 AERODYNAMICS

Aerodynamic is the key in designing any vehicle, especially a

vehicle built for speed. Slipstream design can helps reduce air

resistance, an archenemy of speed. A sloping nose section not

only directs air upwards, it can also provides down force, which

can helps to stabilize the vehicle in high speed.

A bubble canopy, made from high grade polyglass can also

give the car a slipstream design, thus further improving the

aerodynamics of the car.

One section which we haven’t missed is the floor. A lot of

high-performance cars, such as Ferrari and Porsche have a flat

underside of the car. This enables air to pass through and

generates negative lift. Negative lift can helps the car sticks firmly

to the ground during high speed run. We incorporated the flat

underside concept for our prototype.

Wind tunnel image of an F1 car

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Page 14: Kereta Solar

4.4 DRIVE GEAR SELECTION

The image above is our drive train. Unlike many competitors,

we used gear instead of belts. Gears are a vital piece of

engineering, and unlike belting system, slippage is not a problem

in gear systems. Power transfers efficiently, to up to 98%.

The gearing in our solar car is calculated by counting the

number of teeth on both the pinion gear and the secondary gear.

The ratio is as stated below;

Primary gear : secondary gear

8 : 30

Gear ratio 1 : 3.75

These numbers translate as ‘each rotation of the primary

(pinion) gear is equal to 3.75 rotation of the secondary gear’. This

configuration gives us the most efficient speed and torque needed

in the race.

Drive shaft

Secondary gear (30 teeth)

Pinion gear (8 teeth)

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4.5 MATERIAL SELECTION

Thin high density polystyrene sheets.

UHU tube glue

We use the lightest material possible in order to achieve the

maximum power to weight ratio. Sir Isaac Newton famous

Newton's second law stated that the formula F = ma establishes

that as m is more, the force needed to produce the same

acceleration will also be higher. Heavy means more weight. More

weight due to more mass.

We believe by stripping down our car’s weight, we will be

able to leave the competitors in the dust.

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4.6 TYRE SELECTION

The tyres of our solar car is salvaged from a cheap toy which

belongs to Navin’s younger brother. It is very light, made of plastic

and looks nice. Chrome wheels are always a head turner, and the

diameter is excellent for high speed. The wheels, drivetrain and

motor in our solar car are a match made in heaven.

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5. FabricationsOur solar car begins as a sketch (refer appendix). A credit

goes to Ling Jia Wen, the artist of our group. She was able to draw

her ideas, presented and approved by our teachers.

Firstly, we cut the polystyrene sheet using a sharp knife.

Then we glued all the pieces together using UHU tube glue. The

first problem that we encounter is the wheel shaft got stuck on the

polystyrene hole. Our solution is to use a small straw to go

between the shaft and the body.

The solar panel is the last thing that we assemble on the

solar car. Our teacher, Mr Onn Azri raised a question weather to

put the panel on the back or on the front. As a proof of concept, we

run a few tests, with the panel on the front and on the rear. It

turned out that putting the panel directly on the motor makes the

car at least 1 second slower than on the front.

The next problem we face is the steering. At first, the car

tends to swerve to the right on the 3 meter mark. The solution is

simple, just like the rear wheels, we use a small straw, which we

can adjust to steer the car, and thus making the car go straight.

All the calculations and measurement are done with our

teacher. Along the way, we learned the proper way to measure

voltage and current, as well as meter connection to the circuit.

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Voltage measurement

Current measurement

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6. COST

Building a solar car today is quite inexpensive. The main

reason is that the technology has been duplicated by smaller

companies in China. A ‘made in China’ DIY kit can cost as low as

RM15, and can be obtained easily over the internet.

For our project car, we use the lightest material. As our

school cannot support the cost of using of carbon fibers, we use

thin polystyrene sheet. The material is very easy to cut and shape,

plus it is lightweight, perfect for making our prototype.

The total cost of our prototype is as follows;

Solar cell - RM 15.00

DC motor - RM 6.50

Wheels - RM free

Polystyrene - RM 8.00

Stationeries - RM 7.30

Total cost - RM 36.80 #

*winning the 1st place = priceless :p

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7. Trial & errorThese results are collected in the stated date and time.

Date \ Time

In order to calculate the average speed, we take the 3

fastest times and divided them by three. All experiments are done

during hot sunny days.

Fastest speed 1 ;

Fastest speed 2 ;

Fastest speed 3 ;

Average speed ;

Fastest speed is obtained at ____________(time)

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8. Appendix

Early stage of development

Flat underside of the car

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Gear

Solar panel placement, optimum weight balance

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Our solar car

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I. FOREWORD

Tn Hj Abd Sukor Bin Salikin

The Principal

SMK Taman Seri Kluang

86000 Kluang, Johore.

First and foremost, I would like to congratulate our school’s

student for making it to the state’s level of the competition. This is

the first time ever that our students qualify to the state level in the

Science and Technology Carnival.

The solar car race competition is a part of science carnival.

These students show high interest and appreciation towards the

usage of alternative energy source, which is solar. According to

the skills and knowledge provided by our teachers, students are

able to explore science in a way they could not just by studying

theories. The competition allows our student to do practical works.

Finally, it is a hope that our school representatives are able

to go further, up to the national’s final. This will definitely do our

school proud.

______________________.

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