INTRODUCTION

A rechargeable lithium polymer Nokia mobile phone battery

Energizer AA size 2500 mA·h (1.2 V, 3.0  W·h, NiMH) rechargeable cell

A battery bank used for an Uninterruptible power supply in a data center

A rechargeable battery or storage battery is a group of one or more electrochemical

cells. They are known as secondary cells because their electrochemical reactions are

electrically reversible. Rechargeable batteries come in many different shapes and sizes,

ranging anything from a button cell to megawatt systems connected to stabilize an

electrical distribution network. Several different combinations of chemicals are

commonly used, including: lead-acid, nickel cadmium (NiCd), nickel metal hydride

(NiMH), lithium ion (Li-ion), and lithium ion polymer (Li-ion polymer).

Rechargeable batteries have lower total cost of use and environmental impact than

disposable batteries. Some rechargeable battery types are available in the same sizes as

disposable types. Rechargeable batteries have higher initial cost, but can be recharged

very cheaply and used many times.

USAGE AND APPLICATIONS

Rechargeable batteries are used for automobile starters, portable consumer devices, light

vehicles (such as motorized wheelchairs, golf carts, electric bicycles, and electric

forklifts), tools, and uninterruptible power supplies. Emerging applications in hybrid

electric vehicles and electric vehicles are driving the technology to reduce cost and

weight and increase lifetime.[1]

Normally, new rechargeable batteries have to be charged before use; newer low self-

discharge batteries hold their charge for many months, and are supplied charged to about

70% of their rated capacity.

Grid energy storage applications use rechargeable batteries for load leveling, where they

store electric energy for use during peak load periods, and for renewable energy uses,

such as storing power generated from photovoltaic arrays during the day to be used at

night. By charging batteries during periods of low demand and returning energy to the

grid during periods of high electrical demand, load-leveling helps eliminate the need for

expensive peaking power plants and helps amortize the cost of generators over more

hours of operation.

The US National Electrical Manufacturers Association has estimated that U.S. demand

for rechargeable batteries is growing twice as fast as demand for nonrechargeables.[2]

CHARGING AND DISCHARGING

During charging, the positive active material is oxidized, producing electrons, and the

negative material is reduced, consuming electrons. These electrons constitute the current

flow in the external circuit. The electrolyte may serve as a simple buffer for ion flow

between the electrodes, as in lithium-ion and nickel-cadmium cells, or it may be an active

participant in the electrochemical reaction, as in lead-acid cells.

Diagram of the charging of a secondary cell battery.

Battery charger

A solar-powered charger for rechargeable AA batteries

The energy used to charge rechargeable batteries usually comes from a battery charger

using AC mains electricity. Chargers take from a few minutes (rapid chargers) to several

hours to charge a battery. Most batteries are capable of being charged far faster than

simple battery chargers are capable of; there are chargers that can charge consumer sizes

of NiMH batteries in 15 minutes. Fast charges must have multiple ways of detecting full

charge (voltage, temperature, etc.) to stop charging before onset of harmful overcharging.

Rechargeable multi-cell batteries are susceptible to cell damage due to reverse charging if

they are fully discharged. Fully integrated battery chargers that optimize the charging

current are available.

Attempting to recharge non-rechargeable batteries with unsuitable equipment may cause

battery explosion[

Flow batteries, used for specialised applications, are recharged by replacing the

electrolyte liquid.

Battery manufacturers' technical notes often refer to VPC; this is volts per cell, and refers

to the individual secondary cells that make up the battery. For example, to charge a 12 V

battery (containing 6 cells of 2 V each) at 2.3 VPC requires a voltage of 13.8 V across the

battery's terminals.

Non-rechargeable alkaline and zinc-carbon cells output 1.5V when new, but this voltage

gradually drops with use. Most NiMH AA and AAA batteries rate their cells at 1.2 V,

and can usually be used in equipment designed to use alkaline batteries up to an end-

point of 0.9 to 1.2V.

REVERSE CHARGING

Subjecting a discharged cell to a current in the direction which tends to discharge it

further, rather than charge it, is called reverse charging; this damages cells. Reverse

charging can occur under a number of circumstances, the two most common being:

When a battery or cell is connected to a charging circuit the wrong way round.

When a battery made of several cells connected in series is deeply discharged.

When one cell completely discharges ahead of the rest, the live cells will apply a reverse

current to the discharged cell ("cell reversal"). This can happen even to a "weak" cell that

is not fully discharged. If the battery drain current is high enough, the weak cell's internal

resistance can experience a reverse voltage that is greater than the cell's remaining

internal forward voltage. This results in the reversal of the weak cell's polarity while the

current is flowing through the cells[3][4]. This can significantly shortens the life of the

affected cell and therefore of the battery. The higher the discharge rate of the battery

needs to be, the better matched the cells should be, both in kind of cell and state of

charge. In some extreme cases, the reversed cell can begin to emit smoke or catch fire.

In critical applications using Ni-Cad batteries, such as in aircraft, each cell is individually

discharged by connecting a load clip across the terminals of each cell, thereby avoiding

cell reversal, then charging the cells in series.[citation needed]

DEPTH OF DISCHARGE

Depth of discharge (DOD) is normally stated as a percentage of the nominal ampere-hour

capacity; 0% DOD means no discharge. Since the usable capacity of a battery system

depends on the rate of discharge and the allowable voltage at the end of discharge, the

depth of discharge must be qualified to show the way it is to be measured. Due to

variations during manufacture and aging, the DOD for complete discharge can change

over time or number of discharge cycles. Generally a rechargeable battery system will

tolerate more charge/discharge cycles if the DOD is lower on each cycle.[5]

ACTIVE COMPONENTS

The active components in a secondary cell are the chemicals that make up the positive

and negative active materials, and the electrolyte. The positive and negative are made up

of different materials, with the positive exhibiting a reduction potential and the negative

having an oxidation potential. The sum of these potentials is the standard cell potential or

voltage.

In primary cells the positive and negative electrodes are known as the cathode and anode,

respectively. Although this convention is sometimes carried through to rechargeable

systems — especially with lithium-ion cells, because of their origins in primary lithium

cells — this practice can lead to confusion. In rechargeable cells the positive electrode is

the cathode on discharge and the anode on charge, and vice versa for the negative

electrode.

TABLE OF RECHARGEABLE BATTERY TECHNOLOGIES

TypeVoltagea Energy densityb Powerc Effi.d E/$e Disch.f Cyclesg Lifeh

(V) (MJ/kg) (Wh/kg) (Wh/L) (W/kg) (%) (Wh/$) (%/month) (#) (years)

Lead-

acid2.1

0.11-

0.1430-40 60-75 180

70%-

92%5-8 3%-4% 500-800

5-8 (car battery),

20 (stationary)

VRLAi 2.105

Alkaline 1.5 0.31 85 250 50 99.9% 7.7 <0.3 100-1000 <5

Ni-iron 1.2 0.18 50 100 65% 5-7.3[6] 20%-40% 50+

Ni-

cadmium1.2

0.14-

0.2240-60 50-150 150

70%-

90%

1.25-

2.5[6]20% 1500

NIH2 1.5 75 20,000 15+

NiMH 1.20.11-

0.2930-80

140-

300

250-

100066% 2.75 30% 500-1000

Ni-zinc 1.7 0.22 60 170 900 2-3.3 100-500

Li ion 3.6 0.58 150-250250-

3601800

80-

90%2.8-5[7] 5%-10% 1200 2-3

Li

polymer3.7

0.47-

0.72130-200 300 3000+ 2.8-5.0 500~1000 2-3

LiFePO4 3.25 80-120 170 [8] 1400 0.7-3.0 2000+[9]

Li

sulfur[10]2.0

0.94-

1.44[11]400[12] 350 ~100

Li

titanate2.3 90 4000+

87-

95%r

0.5-

1.0[13]9000+ 20+

Thin film

Li ? 350 959  ?  ?p[14] 40000

ZnBr 75-85

V redox1.15-

1.5525-35[15] 80%[16] 20%[16] 14,000[17] 10(stationary)[16]

NaS 15089%-

92%

Molten

salt2.58

70-

110[18]160[6]

150-

2204.54[19] 3000+ 8+

Silver

zinc (Ag-

zinc)

1.86 130 240

NOTES

For brevity, entries in the table had to be abbreviated. For a full description, please refer

to the individual article about each type.

a Nominal cell voltage in V.

Graph of mass and volume energy densities of several secondary cells

b Energy density = energy/weight or energy/size, given in three different units

c Specific power = power/weight in W/kg

d Charge/discharge efficiency in %

e Energy/consumer price in W·h/US$ (approximately)

j Safe Depth of Discharge to maintain lifecycles

f Self-discharge rate in %/month

g Cycle durability in number of cycles

h Time durability in years

i VRLA or recombinant includes gel batteries and absorbed glass mats

p Pilot production

r Depending upon charge rate

COMMON RECHARGEABLE BATTERY TYPES

Nickel-cadmium battery (NiCd)

Created by Waldemar Jungner of Sweden in 1899, based on Thomas Edison's first

alkaline battery. Using nickel oxide hydroxide and metallic cadmium as electrodes.

Cadmium is a toxic element, and was banned for most uses by the European Union in

2004. Nickel-cadmium batteries have been almost completely superseded by nickel-metal

hydride (NiMH) batteries.

NICKEL-METAL HYDRIDE BATTERY (NiMH)

First commercial types were available in 1989.[20] These are now a common consumer

and industrial type. The battery has a hydrogen-absorbing alloy for the negative electrode

instead of cadmium.

LITHIUM-ION BATTERY

The technology behind lithium-ion battery has not yet fully reached maturity. However,

the batteries are the type of choice in many consumer electronics and have one of the best

energy-to-mass ratios and a very slow loss of charge when not in use.

LITHIUM-ION POLYMER BATTERY

These batteries are light in weight and can be made in any shape desired.

LESS COMMON TYPES

Lithium sulfur battery

A new battery chemistry developed by Sion Power since 1994.[21] Claims superior

energy to weight than current lithium technologies on the market. Also lower

material cost may help this product reach the mass market.[22]

Thin film battery (TFB)

An emerging refinement of the lithium ion technology by Excellatron.[23] The

developers claim a very large increase in recharge cycles, around 40,000 cycles.

Higher charge and discharge rates. At least 5C charge rate. Sustained 60C

discharge, and 1000C peak discharge rate. And also a significant increase in

specific energy, and energy density.[24]

Also Infinite Power Solutions makes thin film batteries (TFB) for micro-

electronic applications, that are flexible, rechargeable, solid-state lithium

batteries.

SMART BATTERY

A smart battery has the voltage monitoring circuit built inside. See also: Smart

Battery System

CARBON FOAM-BASED LEAD ACID BATTERY

Firefly Energy has developed a carbon foam-based lead acid battery with a

reported energy density of 30-40% more than their original 38 W·h/kg, [26] with

long life and very high power density.

POTASSIUM-ION BATTERY

This type of rechargeable battery can deliver the best known cycleability, in order

of a million cycles, due to the extraordinary electrochemical stability of potassium

insertion/extraction materials such as Prussian blue.

DEVELOPMENTS SINCE 2005

In 2007 Yi Cui and colleagues at Stanford University's Department of Materials Science

and Engineering discovered that using silicon nanowires as the anode of a lithium-ion

battery increases the volumetric charge density of the anode by up to a factor of 10, the

nanowire battery.

Another development is the paper-thin flexible self-rechargeable battery combining a

thin-film organic solar cell with an extremely thin and highly flexible lithium-polymer

battery, which recharges itself when exposed to light.

Ceramatec, a research and development subcompany of CoorsTek, as of 2009 was testing

a battery comprising a chunk of solid sodium metal mated to a sulfur compound by a

paper-thin ceramic membrane which conducts ions back and forth to generate a current.

The company claimed that it could fit about 40 kilowatt hours of energy into a package

about the size of a refrigerator, and operate below 90 °C; and that their battery would

allow about 3,650 discharge/recharge cycles (or roughly 1 per day for one decade.)[30]

ALTERNATIVES

Several alternatives to rechargeable batteries exist or are under development. For uses

such as portable radios, rechargeable batteries may be replaced by clockwork

mechanisms which are wound up by hand, driving dynamos, although this system may be

used to charge a battery rather than to operate the radio directly. Flashlights may be

driven by a dynamo directly. For transportation, uninterruptible power supply systems

and laboratories, flywheel energy storage systems store energy in a spinning rotor for

conversion to electric power when needed; such systems may be used to provide large

pulses of power that would otherwise be objectionable on a common electrical grid.

Ultracapacitors are also used; an electric screwdriver which charges in 90 seconds and

will drive about half as many screws as a device using a rechargeable battery was

introduced in 2007, and similar flashlights have been produced.

Ultracapacitors—capacitors of extremely high value—are being developed for

transportation, using a large capacitor to store energy instead of the rechargeable battery

banks used in hybrid vehicles. One drawback to capacitors compared with batteries is that

the terminal voltage drops rapidly; a capacitor that has 25% of its initial energy left in it

will have one-half of its initial voltage. Battery systems tend to have a terminal voltage

that does not decline rapidly until nearly exhausted. This characteristic complicates the

design of power electronics for use with ultracapacitors. However, there are potential

benefits in cycle efficiency, lifetime, and weight compared with rechargeable systems.

China started using ultracapacitors on two commercial bus routes in 2006; one of them is

route 11 in Shanghai.

BATTERY CHARGER

http://en.wikipedia.org/wiki/File:BatteryCharger1.jpg

This unit charges the batteries until they reach a specific voltage and then it trickle

charges the batteries until it is disconnected.

A simple charger equivalent to a AC/DC wall adapter. It applies 300mA to the battery at

all times, which will damage the battery if left connected too long.

A battery charger is a device used to put energy into a secondary cell or (rechargeable)

battery by forcing an electric current through it.

The charge current depends upon the technology and capacity of the battery being

charged. For example, the current that should be applied to recharge a 12 V car battery

will be very different from the current for a mobile phone battery.

TYPES OF BATTERY CHARGERS

SIMPLE

A simple charger works by supplying a constant DC power source to a battery being

charged. The simple charger does not alter its output based on time or the charge on the

battery. This simplicity means that a simple charger is inexpensive, but there is a tradeoff

in quality. Typically, a simple charger takes longer to charge a battery to prevent severe

over-charging. Even so, a battery left in a simple charger for too long will be weakened

or destroyed due to over-charging. These chargers can supply either a constant voltage or

a constant current to the battery.

TRICKLE

A trickle charger, also known as a battery trickle charger, is typically a low amperage

(500-1,500mA) battery charger. A trickle charger is generally used to charge small

capacity batteries (2-30Ah[1]). These types of battery chargers are also used to maintain

larger capacity batteries (>30Ah) that are typically found on cars, boats, RVs and other

related vehicles. Utilizing the battery charger is this fashion, is how these battery chargers

got their name. In larger application, the current of the battery charger is only sufficient

to provide a maintenance or trickle current (trickle is commonly the last charging stage of

most battery chargers. Depending on the technology of the trickle charger, it can be left

connected to the battery indefinitely. Battery chargers that can be left connected to the

battery without causing the battery damage are also referred to as smart or intelligent

chargers. Trickle is merely another name for a low current battery charger.

TIMER-BASED

The output of a timer charger is terminated after a pre-determined time. Timer chargers

were the most common type for high-capacity Ni-Cd cells in the late 1990s for example

(low-capacity consumer Ni-Cd cells were typically charged with a simple chargers).

Often a timer charger and set of batteries could be bought as a bundle and the charger

time was set to suit those batteries. If batteries of lower capacity were charged then they

would be overcharged, and if batteries of higher capacity were charged they would be

only partly charged. With the trend for battery technology to increase capacity year on

year, an old timer charger would only partly charge the newer batteries.

Timer based chargers also had the drawback that charging batteries that were not fully

discharged, even if those batteries were of the correct capacity for the particular timed

charger, would result in over-charging.

INTELLIGENT

Output current depends upon the battery's state. An intelligent charger may monitor the

battery's voltage, temperature and/or time under charge to determine the optimum charge

current at that instant. Charging is terminated when a combination of the voltage,

temperature and/or time indicates that the battery is fully charged.

For Ni-Cd and NiMH batteries, the voltage across the battery increases slowly during the

charging process, until the battery is fully charged. After that, the voltage decreases,

which indicates to an intelligent charger that the battery is fully charged. Such chargers

are often labeled as a ΔV, "delta-V," or sometimes "delta peak", charger, indicating that

they monitor the voltage change.

The problem is, the magnitude of "delta-V" can become very small or even non-existent

if (very) high capacity rechargeable batteries are recharged.[citation needed] This can cause even

an intelligent battery charger to not sense that the batteries are actually already fully

charged, and continue charging. Overcharging of the batteries will result in some cases.

However, many so called intelligent chargers employ a combination of cut off systems,

which should prevent overcharging in the vast majority of cases.

A typical intelligent charger fast-charges a battery up to about 85% of its maximum

capacity in less than an hour, then switches to trickle charging, which takes several hours

to top off the battery to its full capacity.

FAST

Fast chargers make use of control circuitry in the batteries being charged to rapidly

charge the batteries without damaging the cells' elements. Most such chargers have a

cooling fan to help keep the temperature of the cells under control. Most are also capable

of acting as standard overnight chargers if used with standard NiMH cells that do not

have the special control circuitry. Some fast chargers, such as those made by Energizer,

can fast-charge any NiMH battery even if it does not have the control circuit.

PULSE

Some chargers use pulse technology in which a pulse is fed to the battery. This DC pulse

has a strictly controlled rise time, pulse width, pulse repetition rate (frequency) and

amplitude. This technology is said to work with any size, voltage, capacity or chemistry

of batteries, including automotive and valve-regulated batteries.[3] With pulse charging,

high instantaneous voltages can be applied without overheating the battery. In a Lead-

acid battery, this breaks down lead-sulfate crystals, thus greatly extending the battery

service life.[4]

Several kinds of pulse charging are patented. Others are open source hardware.

Some chargers use pulses to check the current battery state when the charger is first

connected, then use constant current charging during fast charging, then use pulse

charging as a kind of trickle charging to maintain the charge.[9]

Some chargers use "negative pulse charging", also called "reflex charging" or "burp

charging".[10] Such chargers use both positive and brief negative current pulses. There is

no significant evidence, however, that negative pulse charging is more effective than

ordinary pulse charging.

INDUCTIVE

Inductive battery chargers use electromagnetic induction to charge batteries. A charging

station sends electromagnetic energy through inductive coupling to an electrical device,

which stores the energy in the batteries. This is achieved without the need for metal

contacts between the charger and the battery. It is commonly used in electric toothbrushes

and other devices used in bathrooms. Because there are no open electrical contacts, there

is no risk of electrocution.

USB-BASED

Pay-per-charge kiosk, illustrating the variety of mobile phone charger connectors

Since the Universal Serial Bus specification provides for a five-volt power supply, it is

possible to use a USB cable as a power source for recharging batteries. Products based on

this approach include chargers for cellular phones and portable digital audio players.

They may be fully compliant USB peripheral devices adhering to USB power discipline,

or uncontrolled in the manner of USB decorations.

SOLAR CHARGERS

Solar chargers convert light energy into DC current. They are generally portable, but can

also be fixed mount. Fixed mount solar chargers are also known as solar panels. Solar

panels are often connected to the electrical grid, where as portable solar chargers as used

off-the-grid (i.e. cars, boats, or RVs).

Although portable solar chargers obtain energy from the sun only, they still can

(depending on the technology) be used in low light (i.e. cloudy) applications. Portable

solar charger are typically used for trickle charging, although some solar charger

(depending on the wattage), can completely recharge batteries. Although Portable wind

turbines are also sold. Some, including the Kinesis K3, can work either way.

CHARGE RATE

Charge rate is often denoted as C or C-rate and signifies a charge or discharge rate equal

to the capacity of a battery in one hour.[13] For a 1.6Ah battery, C = 1.6A. A charge rate of

C/2 = 0.8A would need two hours, and a charge rate of 2C = 3.2A would need 30 minutes

to fully charge the battery from an empty state, if supported by the battery. This also

assumes that the battery is 100% efficient at absorbing the charge.

APPLICATIONS

Since a battery charger is intended to be connected to a battery, it may not have voltage

regulation or filtering of the DC voltage output. Battery chargers equipped with both

voltage regulation and filtering may be identified as battery eliminators.

MOBILE PHONE CHARGER

Micro USB mobile phone charger

Most mobile phone chargers are not really chargers, only adapters that provide a power

source for the charging circuitry which is almost always contained within the mobile

phone. They are notably diverse, having a wide variety of DC connector-styles and

voltages, most of which are not compatible with other manufacturers' phones or even

different models of phones from a single manufacturer.

Users of publicly accessible charging kiosks must be able to cross-reference connectors

with device brands/models and individual charge parameters and thus ensure delivery of

the correct charge for their mobile device. A database-driven system is one solution, and

is being incorporated into some designs of charging kiosks.

Mobile phones can usually accept relatively wide range of voltages[citation needed], as long as

it is sufficiently above the phone battery's voltage. However, if the voltage is too high, it

can damage the phone. Mostly, the voltage is 5 volts or slightly higher, but it can

sometimes vary up to 12 volts when the power source is not loaded.

There are also human-powered chargers sold on the market, which typically consists of a

dynamo powered by a hand crank and extension cords. There are also solar chargers.

China and other countries are making a national standard on mobile phone chargers using

the USB standard.[15] Starting in 2010, SonyEricsson, Apple, Nokia, Motorola, Samsung

and RIM will begin making handsets with a standard phone charger based on the micro-

USB connector.[16] On October 22, 2009 the International Telecommunication Union

announced a standard for a universal charger for mobile handsets (Micro-USB).[17]

BATTERY CHARGER FOR VEHICLES

There are two main types of charges for vehicles:

To recharge a fuel vehicle's starter battery, where a modular charger is used.

To recharge an electric vehicle (EV) battery pack.

BATTERY ELECTRIC VEHICLE

These vehicles include a battery pack, so generally use series charger.

A 10 Ampere-hour battery could take 15 hours to reach a fully charged state from a fully

discharged condition with a 1 Ampere charger as it would require roughly 1.5 times the

battery's capacity.

Public EV charging heads (aka: stations) provide 6 kW (host power of 208 to 240 VAC

off a 40 amp circuit). 6 kW will recharge an EV roughly 6 times faster than 1 kW

overnight charging.

Rapid charging results in even faster recharge times and is only limited by available AC

power and the type of charging system.

On board EV chargers (change AC power to DC power to recharge the EV's pack) can

be:

Isolated: they make no physical connection between the A/C electrical mains and

the batteries being charged. These typically employ some form of Inductive

charging. Some isolated chargers may be used in parallel. This allows for an

increased charge current and reduced charging times. The battery has a maximum

current rating that cannot be exceeded

Non-isolated: the battery charger has a direct electrical connection to the A/C

outlet's wiring. Non-isolated chargers cannot be using in parallel.

Power Factor Correction (PFC) chargers can more closely approach the maximum

current the plug can deliver, shortening charging time.

CHARGE STATIONS

There is a list of public EV charging stations in the U.S.A. and worldwide[18]

Project Better Place is deploying a network of charging stations and subsidizing vehicle

battery costs through leases and credits.

Auxiliary charger designed to fit a variety of proprietary devices

Non-contact magnetic charging

Researchers at the Korea Advanced Institute of Science and Technology (KAIST) have

developed an electric transport system (called Online Electric Vehicle, OLEV) where the

vehicles get their power needs from cables underneath the surface of the road via non-

contact magnetic charging, (where a power source is placed underneath the road surface

and power is wirelessly picked up on the vehicle itself. As a possible solution to traffic

congestion and to improve overall efficiency by minimizing air resistance and so reduce

energy consumption, the test vehicles followed the power track in a convoy formation[20]

USE IN EXPERIMENTS

A battery charger can work as a DC power adapter for experimentation. It may, however,

require an external capacitor to be connected across its output terminals in order to

"smooth" the voltage sufficiently, which may be thought of as a DC voltage plus a

"ripple" voltage added to it. Note that there may be an internal resistance connected to

limit the short circuit current, and the value of that internal resistance may have to be

taken into consideration in experiments.

PROLONGING BATTERY LIFE

Many rumors circulate about the best practices to prolong battery life. What practices are

best depend on the type of battery. It is "rumored" that Nickel-based cells, such as NiMH

and NiCd, need to be fully discharged before each charge, or else the battery loses

capacity over time in a phenomenon known as "memory effect". However, this is only

partially accurate: nickel alloy cells can be charged at any point throughout their

discharge cycle – they do not have to be fully discharged. Memory effect should instead

be prevented by fully discharging the battery once a month (once every 30 charges). [21]

This extends the life of the battery since memory effect is prevented while avoiding full

charge cycles which are known to be hard on all types of dry-cell batteries, eventually

resulting in a permanent decrease in battery capacity.

Most modern cell phones, laptops, and most electric vehicles use Lithium-ion batteries.

Contrary to some recommendations, these batteries actually last longest if the battery is

frequently charged; fully discharging them will degrade their capacity relatively quickly.[21] When storing however, lithium batteries degrade more while fully charged than if they

are only 40% charged. Degradation also occurs faster at higher temperatures.

Degradation in lithium-ion batteries is caused by an increased internal battery resistance

due to cell oxidation. This decreases the efficiency of the battery, resulting in less net

current available to be drawn from the battery.[citation needed]

Internal combustion engine vehicles, such as boats, RVs, ATVs, motorcycles, cars,

trucks, and more use lead acid batteries. These batteries employ a sulfuric acid electrolyte

and can generally be charged and discharged without exhibiting memory effect, though

sulfation (a chemical reaction in the battery which deposits a layer of sulfates on the lead)

will occur over time. Keeping the electrolyte level in the recommended range is

necessary. When discharged, these batteries should be recharged immediately in order to

prevent sulfation. These sulfates are electrically insulating and therefore interfere with the

transfer of charge from the sulfuric acid to the lead, resulting in a lower maximum current

than can be drawn from the battery. Sulfated lead acid batteries typically need replacing.

REFERENCES

1. http://www.geniuschargers.com

2. Dave Etchells. "The Great Battery Shootout". http://www.imaging-

resource.com/ACCS/BATTS/BATTS.HTM.

3. "AN913: Switch-Mode, Linear, and Pulse Charging Techniques for Li+ Battery in

Mobile Phones and PDAs". Maxim. 2001.

http://www.maxim-ic.com/appnotes.cfm/appnote_number/913/.

4. "Lead-acid battery sulfation". Archived from the original on 2007-04-02.

http://web.archive.org/web/20070402140958/http://www.dallas.net/~jvpoll/

Battery/aaPictures.html.

5. ""fast pulse battery charger" patent". 2003. http://www.wipo.int/pctdb/en/wo.jsp?

wo=2003088447.

6. "Battery charger with current pulse regulation" patented 1981 United States

Patent 4355275

7. "Pulse-charge battery charger" patented 1997 United States Patent 5633574

8. http://www.dallas.net/~jvpoll/Battery/aaPictures.html Pulse-charger/desulfator

circuit schematic

9. "Pulse Maintenance charging."

CONTENTS

INTRODUCTION

USAGE AND APPLICATIONS

CHARGING AND DISCHARGING

REVERSE CHARGING

DEPTH OF DISCHARGE

ACTIVE COMPONENTS

COMMON RECHARGEABLE BATTERY TYPES

ALTERNATIVES

BATTERY CHARGER

TYPES OF BATTERY CHARGERS

CHARGE RATE

USE IN EXPERIMENTS

PROLONGING BATTERY LIFE