We believe in providing our customers with the resources necessary in making an informed decision about their battery needs. The articles provider here have been written as a quick reference to all your battery needs. If you don't find what you are looking for please feel free to call us and we will do our best to assist you.

 

Battery Care Instructions
What should I know about Memory Effect?
Battery Charger Options
Should I Store my Batteries in the Refrigerator?
My New Battery Isn't Charging. What's the Deal? Is there a break-in procedure?
Getting the Most from your Laptop Battery
iPod Battery Care Tips
Battery Charger Usage Tips
Battery Rebuilds/Refurbishing
Voltage and Amperage for Replacement Batteries
Why Batteries Need Replacing
How heat affects batteries

 

Maximizing Battery Performance

Sealed Lead Acid Battery Care

Battery Disposal

Upcoming Battery Breakthroughs

 

Battery Do's:

• A new battery comes in a discharged condition and must be charged before use (refer to the devices manual for charging instructions). Upon initial use (or after a prolonged storage period) the battery may require three to four charge/discharge cycles before achieving maximum capacity.
• When charging the battery for the first time the device may indicate that charging is complete after just 10 or 15 minutes. This is a normal phenomenon with rechargeable batteries. Remove the battery from the device, reinsert it and repeat the charging procedure.
• It is important to condition (fully discharge and then fully charge) the battery every two to three weeks. Failure to do so may significantly shorten the battery's life (this does not apply to Li-Ion batteries, which do not require conditioning). To discharge, simply run the device under the battery's power until it shuts down or until you get a low battery warning. Then recharge the battery as instructed in the user's manual.
• If the battery will not be in use for a month or longer, it is recommended that it be removed from the device and stored in a cool, dry, clean place.
• It is normal for a battery to become warm to the touch during charging and discharging.
• A charged battery will eventually lose its charge if unused. It may therefore be necessary to recharge the battery after a storage period.
• The milliamp-hour (mAh) rating of the Hi-Capacity battery will often be higher than the one on the original battery. A higher mAH rating is indicative of a longer lasting (higher capacity) battery and will not cause any incompatibilities. A Hi-Capacity battery will, in most cases, outperform the original by 30% to 50%.
• Actual battery run-time depends upon the power demands made by the equipment. In the case of notebook computers, screen brightness, the use of the CPU, the hard drive, and other peripherals results in an additional drain upon the battery, effectively reducing the battery's run-time. The total run-time of the battery is also heavily dependent upon the design of the equipment. To ensure maximum performance of the battery, optimize the computer's power management features. Refer to the computer manual for further instructions.A

Battery Don'ts:

• Do not short-circuit. A short-circuit may cause severe damage to the battery.
• Do not drop, hit or otherwise abuse the battery as this may result in the exposure of the cell contents, which are corrosive.
• Do not expose the battery to moisture or rain.
• Keep battery away from fire or other sources of extreme heat. Do not incinerate. Exposure of battery to extreme heat may result in an explosion.

 

What is the "Memory Effect"?

NiCad batteries, and to a lesser extent NiMH batteries, suffer from what's called the "memory effect". What this means is that if a battery is repeatedly only partially discharged before recharging, the battery "forgets" that it has the capacity to further discharge all the way down. To illustrate: If you, on a regular basis, fully charge your battery and then use only 50% of its capacity before the next recharge, eventually the battery will become unaware of its extra 50% capacity which has remained unused. The battery will remain functional, but only at 50% of its original capacity. The way to avoid the dreaded "memory effect" is to fully cycle (fully charge and then fully discharge) the battery at least once every two to three weeks. Batteries can be discharged by unplugging the device's AC adapter and letting the device run on the battery until it ceases to function. This will insure your battery remains healthy.

 

Battery Charger Options

When rechargeable batteries were first introduced, the technology was unpolished and the applications seemed few and far between. Since that time, this technology has been refined and reinvented to allow application in many useful settings. With rechargeable batteries quickly becoming the norm in many of the devices we use every day, it is only appropriate that we examine some of the different options available for recharging batteries.

Charging a battery may seem like a simple, necessary task that does not require a lot of explaining. The average person usually gets home, pulls out their mobile phone, and plugs it in before going to bed. Or some may use their laptop with the AC adapter connected at all times. In both of these cases, batteries are being recharged. However, these charging practices may be less than ideal. That being said, here are some options available for charging your rechargeable batteries.

For camcorders, many people simply use the AC adapter that came with the camera to charge the battery through the camera itself. What many people do not realize is that external chargers are available for most camcorder batteries. The benefits of these external chargers are numerous. For instance, it is always possible to buy more than one battery so that one can charge on the external charger while the other is being used, ensuring backup power is always available. Also, these chargers are usually able to be used with both a standard wall outlet and a car's cigarette lighter, meaning the battery can be charged on your way to where you will be filming. All of the above information applies to digital camera batteries as well.

Surely, the average mobile phone user is quite familiar with two of the most common mobile phone chargers: a home (travel) charger and a car charger. These chargers meet the needs of a large majority of cell phone owners. However, these are not the only charging options for these phones. Some phones have optional charging bases that allow the phone to charge while another battery is charged externally and simultaneously. Other desktop chargers serve a double purpose by charging the battery and syncing the mobile phone to a computer. Finally, portable "chargers" are becoming more popular for cell phones as they allow the use of common batteries such as AA's to be used to quickly put a charge on the mobile phone battery for an emergency call.

Lastly, we can see that, as laptops become more common, affordable, and powerful, the need for adequate power is a huge one. Since many laptop batteries are only able to power the computer for about 3 hours or less, many users find themselves always tethered to a wall somewhere so they can use the laptop on AC power. However, portability is an overwhelming necessity for those who rely on their laptops on photo shoots, business trips, etc. In these cases, it is always an option to purchase a second battery and swap them out when needed. A battery just like the one included with the computer may be the best option if a dual charger is available for your laptop model. These chargers charge one or two batteries externally by plugging into a standard wall outlet. If this type of charger is not available, then an external laptop battery may be appropriate. These batteries charge on their own when connected to a standard wall outlet. Then, the battery may be plugged into the laptop's charger port in order to power the laptop for extended periods of time that the internal battery cannot handle.

With all of these charging options available, no one should ever be left in the dark, disconnected, or cut off in the middle of a project. Keep your devices up and running with one or several of the many charging options available for your device.

 

 

Should I Store my Batteries in the Refrigerator?

I've heard storing batteries in the refrigerator makes them last longer. Is it true?

 

Many people have been told that storing alkaline batteries in the refrigerator actually prolongs the battery life. But before you start mixing apples and alkaline, there are some things you should know.

The concept of refrigerating batteries originated from a time when batteries were predominately made with mercury. Many people, photographers especially, sought to decrease the amount of mercury dispelled from these batteries while not in use by storing them in colder temperatures. Eventually, it was discovered that the refrigerator was a great place to accomplish this. Then, in the 80's, the U.S. government outlawed the sale of mercury batteries due to health concerns. Since then, alkaline batteries have all but replaced the once-dominant mercury cells. Alkaline batteries do not reap the same benefits of refrigerated storage as mercury cells do. Most battery manufacturers still suggest storing your cells at room temperature or slightly below. Most people can get by with storing their alkaline batteries in a jar in a cabinet. Rechargeable batteries are the same way, but you should be careful not to store them for very long without charging them periodically. Rechargeable batteries that are stored for a long time without being charged have a tendency to run down very quickly. Technically, you won't do any harm to your batteries by refrigerating them. But unless you happen to have a mercury battery lying around, you should probably save room for other, more edible items.

 

My New Battery Isn't Charging. What's the Deal? Is there a break-in procedure?

New batteries are shipped in a discharged condition and must be charged before use. We generally recommend an overnight charge (approximately twelve hours). Refer to the user's manual for charging instructions. Rechargeable batteries should be cycled - fully charged and then fully discharged - two to four times initially to allow them to reach their full capacity. (Note: it is normal for a battery to become warm to the touch during charging and discharging).

New batteries are hard for the device to charge; they have never been fully charged and are therefore "unformed". Sometimes the device's charger will stop charging a new battery before it is fully charged. If this happens, remove the battery from the device and then reinsert it. The charge cycle should begin again. This may happen several times during the first battery charge. Don't worry; it's perfectly normal.


How Can I Maximize Battery Performance?

There are several steps you can take to insure that you get maximum performance from the battery: Break In New Batteries New batteries come in a discharged condition and must be fully charged before use. It is recommended that you fully charge and discharge the new battery two to four times to allow it to reach its maximum rated capacity.

Keep the battery healthy by fully charging and then fully discharging it at least once every two to three weeks. Exceptions to the rule are Li-Ion batteries, which do not suffer from the memory effect.

It's a good idea to clean dirty battery contacts with a cotton swab and alcohol. This helps maintain a good connection between the battery and the portable device.

Exercise the Battery
Do not leave the battery dormant for long periods of time. We recommend using the battery at least once every two to three weeks. If a battery has not been used for a long period of time, perform the new battery break in procedure described above.

Battery Storage
If you don't plan on using the battery for a month or more, we recommend storing it in a clean, dry, cool place away from heat and metal objects. NiCad, NiMH and Li-Ion batteries will self-discharge during storage; remember to break them in before use. Sealed Lead Acid (SLA) batteries must be kept at full charge during storage. This is usually achieved by using special trickle chargers. If you do not have a trickle charger, do not attempt to store SLA batteries for more than three months.

For Notebook Users
To get maximum performance from the battery, fully optimize the notebooks power management features prior to use. Power management is a trade off: better power conservation in exchange for lesser computer performance. The power management system conserves battery power by setting the processor to run at a slower speed, dimming the screen, spinning down the hard drive when it's not in use and causing the machine to go into sleep mode when inactive. The notebook users guide will provide information relating to specific power management features.

 

Getting the Most from your Laptop Battery

There are several steps you can take to make sure your laptop battery lives up to its potential. With more and more computers running more and more programs and peripherals, these tips can come in handy next time your away from a wall outlet.

Tweak your settings
See your Operating System resources to determine how to change your hardware settings. Make sure that the screen brightness is set to the lowest level that lets you see the screen comfortably. Also, set your system hibernate after a few minutes so your computer doesn't sit and run while you're away. Some systems even allow you to change how long the hard drive will run, allowing you to free up even more battery life.

Unplug peripherals
Leaving cameras, USB drives, and speakers plugged in when not in use is one of the biggest power consumers. When you're done with a file on a thumb drive, go ahead and remove it. If you aren't using the CD in your disk drive, remove that as well to keep the disk drive from running constantly.

Is it really a "lap"-top?
Some sources indicate that using your laptop in your lap causes the system to heat up rapidly. In this case, your cooling system will begin to work overtime. If you notice your computer getting pretty hot, try to use it on a completely flat surface so the vents around the bottom have room to breathe.

Condition the battery.
Finally, when receiving a new battery, make sure you charge it all the way up at least twice and run it down to about 5% at least twice. This will allow the battery to reach its full capacity and last as long as it is supposed to. Some people also suggest to do this complete discharge/charge cycle about once a month.

iPod Battery Care Tips

The realm of digital music players has a verifiable leader: the Apple iPod. This little device is in many homes, backpacks, and pockets across the nation. The name iPod is synonymous with music and video. But sometimes the battery life of iPod doesn't exactly keep pace with a user's appetite for entertainment. That being said, here are some things you can do to prolong the runtime of your iPod battery and keep your tunes playing without interruptions.

Put it to sleep

Perhaps the easiest thing you can do to keep your iPod battery from running low too quickly is to put it to sleep while you aren't using this. This can be done by holding the play/pause button until the screen turns off. This will save the battery, but leaving an iPod in sleep mode for several days or more will still result in battery loss. It is a good idea to charge the iPod every now and then even when it isn't used much.

Don't Skip

For those of you who are never content with the current song or video and want to see what's coming next, try to refrain from too much skipping. The iPod is designed to play continuously for long periods of time, but skipping songs will quickly drain battery life. Also, when the iPod is in shuffle mode, the battery will drain quicker.

Watch Movies on a TV

One of the most attractive things about the new 5th Generation and 5.5 Generation iPods is their ability to play videos. iTunes even offers movie and TV show downloads for these devices. However, while watching video on the go seem appealing, it may be about the only thing you get to do with your iPod for the day. Video playback drains the iPod battery quicker than anything. If you have a short video to watch while riding to work or on an airplane, go right ahead. But, if you need to have a Lord of the Rings marathon, I suggest you do it at home.

Counter-Clockwise is the Way to Go

Another attractive aspect of the iPod is the click-wheel, a small circular controller used by sliding the thumb around it in either direction to scroll songs, increase volume, etc. For the battery-optimized iPod, counter clockwise is your friend. In other words, less is more. Lower settings in screen brightness, volume, etc. ultimately equal better battery life. Put the screen brightness at the lowest comfortable level. Keep the volume at a low point that is still easily heard. Doing these things will add precious minutes to your playback time.

 

Battery Charger Usage Tips

• Always check charger cord and contacts for signs of wearing or damage. If charger is damaged, discontinue use.
• Always attach your device to the charger before plugging the charger into the wall.
• Unless your device is capable of automatically terminating the charge after full capacity is reached, avoid leaving your device plugged into the charger for prolonged periods of time.
• If you buy a replacement battery, make sure your original charger is compatible. Some extended-life batteries perform better with upgraded chargers.
• Avoid using car chargers very often, as they charge at a higher rate and will often shorten the life of your battery.
• Keep spare chargers at the office and for travel to avoid losing the only charger you have.
• When applicable, always connect the positive terminal first, followed by the negative terminal.
• Never try to recharge a non-rechargeable battery.

 

Battery Rebuilds/Refurbishing

When dealing with rechargeable batteries, it is inevitable that they will eventually die. Any rechargeable battery is good for about 200-300 charge cycles. Once this number is reached, the battery may cease to hold a charge. While the logical choice for a solution seems to be purchasing a new battery, there are some instances when this is not an option. When this is the case, reviving the old battery may be an alternative worth considering.
There is a difference between battery refurbishing and battery rebuilds, although the terms are often used interchangeably by mistake. Battery refurbishing is often performed by a special machine to which the old batteries are connected. This machine sends small, short electrical pulses through the contacts of the battery. This serves to clean the plates of the battery by knocking off any accumulation that may have built up over a long period of use. These machines also have the ability to perform several charge/drain cycles in short period of time, which may alleviate any memory effect that may be present in the battery.
Battery rebuild are a completely different service. Battery rebuilds are usually performed on batteries that are made up of several smaller batteries called cells. The service is very popular for power tool batteries, older style laptop batteries, and custom battery packs. When a battery is rebuilt, it is dismantled and replaced with new cells while using the same wires, contacts, and other components. The benefit of this is that the rebuilt battery is basically a new battery, with only the external parts being reused. Sometimes, the rebuilt battery is even stronger and longer-lasting than the original, since stronger cells can be inserted. Another benefit of this service is that the new battery is able to be used in the existing chargers and devices for which it was originally intended. Finally, the main benefit of this service is the price, which is often half the price of purchasing a new battery.
While both of these services are capable of improving battery performance, battery refurbishing is sometimes unsuccessful in reviving batteries. You can make a decision on trying one of these methods based on your circumstances. Many local battery dealers possess battery refurbishing capabilities.

 

Voltage and Amperage for Replacement Batteries

Rechargeable batteries are rated by manufacturers using voltage, amperage, and sometimes wattage. These ratings are usually listed directly on the battery itself, shown as xV. and xx mAh. Many people notice that the replacement battery they are about to purchase does not match exactly with the voltage and amperage rating of their original battery. Also, several questions often arise about the meaning of "amps", "milliamps", "watts", etc. This article will address some of these questions and provide useful information about replacement batteries.

Voltage
The volts of a battery refer to an electrical measure of energy potential. They indicate how much electric charge is available to the device from the battery. This number is usually printed directly on the original battery, allowing one to easily compare their original voltage rating with the voltage rating on the replacement battery. Replacement batteries should only be purchased when the voltage is reasonably close to that of the original battery. So, if the original battery is a 3.6 volt, a 3.7 volt replacement battery will work perfectly fine. However, a 7.2 volt battery may cause damage to the device in which it is used.

Amperage
"Amps" is an abbreviation of Ampere, a 19th century French scientist. This term refers to the capacity of the battery in terms of runtime. Many batteries use the term "amp hours", but this does not translate directly into actual hours because different devices put different amounts of strain on the battery. Many batteries also use the term "milliamps" of "mAh". This is simply a different way of saying amps, as 1 amp is equal to 1000 mAh. There is significantly more freedom available when choosing a replacement battery in terms of amps. Increasing the amperage in the replacement battery will only increase the amount of time the battery can power the device before it needs to be recharged. For all intents and purposes, the only limiting factor in choosing a replacement battery in terms of amps is size, as batteries higher in amps are often larger in physical size.

Watts
Watts are less frequently used in classifying batteries. This term can be though of as simply the voltage of a battery multiplied by the amperage of the battery. Although this term may be less helpful in determining the exact output of a replacement battery, the replacement battery chosen should be fairly close in wattage to the original battery.

Conclusion
Replacement batteries are often different from original batteries in terms of voltage and amperage due to the fact that they are often manufactured to be compatible with several different devices. While this may deter the average consumer from purchasing a replacement battery for fear of incompatibility, it is perfectly safe to use a replacement battery in any device as long as it meets or exceeds manufacturer standards. A difference in voltage is no reason to rule out a replacement battery, although the difference should be somewhat small. A difference in amperage will simply dictate the runtime of the battery, and can be altered according to the consumer's needs. The only real limiting factor in this area is the physical size changes of replacement batteries with different amperage ratings.

 

Why Batteries Need Replacing

Common reasons for "end of battery life" fall into a limited number of categories.

1.  Needs recharge only / still serviceable:

A recent study has shown that up to 15% of batteries replaced are simply flat or partially discharged. Batteries that are flat or partially discharged, and which can be fully restored after recharging, can be re-installed in the customer's vehicle. It is important to test all batteries being replaced, as there may be a problem with the vehicle's electrical system.

2.  Usage related failure:

This occurs when a battery has prematurely failed due to extreme conditions of use commonly found in harsh climates.
Such failures include:

• Low electrolyte levels expose the busbar and ultimately the upper portion of the plates that can cause irreversible sulphation, and can accelerate corrosion.The low electrolyte levels can be the result of lack of battery maintenance, or as a result of overcharging where fluid is lost through gassing.  As an additional problem, the acid concentration in the battery from lowerelectrolyte levels can cause increased corrosion of the remaining 'wet' part of plates. Batteries with higher electrolyte volume above the plates assist in
minimizing these problems, and ensuring batteries are regularly maintained when operating in harsh conditions will also prolong battery life.
• High under bonnet operating temperature. Harsh operating conditions, and increasing vehicle under bonnet operating temperatures, can cause early battery failure through a number of areas. These conditions contribute to corrosion of the positive plate, grid growth which can result in a short circuit, and loss of plate active material.
• Vibration effects. This can cause physical damage to battery components and often sudden failure of the battery.
  Vibration damage can include:
  -  Loss of active material from the plates, resulting in a loss of battery charge and possible short circuits.
  -  broken or cracked grid frames, causing short circuits; usually causing separator damage.
  -  perforation of the separator envelopes at the bottom where the plates sit in the battery case.  This can result in short circuits.
• Overcharging. Where the vehicle charging system has been operating at a higher than normal voltage, the battery is subjected to virtually continuous charging. This can result in faster grid corrosion, loss of plate active material, loss of electrolyte, plate growth and eventually disintegration of the positive plate.
• Undercharging. This can occur when the vehicle voltage charging system is too low to fully recharge the battery. The result is a loss of charge and irreversible sulphation of the battery.

3.  Plate or Grid Related Corrosion:

• Grid corrosion of the Positive plates within a battery is a normal 'end of battery life' condition that is commonly caused due to higher operating temperatures, overcharging or loss of electrolyte fluid.  Of the positive and negative plates within a battery, it is the positive plates where the grid metal can completely
oxidize and disintegrate due to these operating conditions. Different alloys added to the positive grid lead can have an affect on the corrosion rate. Antimonies lead grids generally have a higher corrosion resistance than calcium lead grids, and along with higher volumes of electrolyte above the plates, can help overcome this problem, allowing batteries to operate more successfully in harsh conditions.
• Soft Positive Plate Material ("mushy plates").  This is a condition usually resulting from high operating temperatures or overcharging.  Often, both conditions may have occurred.
• Sulphation. This occurs when a battery stands in a partially or fully discharged state for long periods of time, or is continually undercharged.  As a result of these conditions the active lead material on the plates becomes lead sulphate which also hardens the plates.   Depending on the length of time the battery has been in this condition, the sulphation may be irreversible.  In addition, if the electrolyte level in the battery is low, the exposed part of the plates will become inactive and sulphated. Therefore batteries with higher electrolyte levels will go a long way to reducing problems due to sulphation and assisting longer battery life.

4.  Open Circuit:

Including causes such as:

• Broken cell to cell connection.   This is where there has been a complete failure of the intercell weld.  Weld quality is critical for reliable battery performance and good working life.  This problem is largely
minimized by manufacturers like Century Yuasa Batteries and other leading manufacturers, due to accredited quality assured manufacturing processes.
• A broken busbar.This type of failure can be caused by excessive corrosion of the busbar due to low electrolyte level in the battery.  Extensive overcharging and/or elevated operating temperatures can also lead to accelerated corrosion of the busbars leading to breakage and and open circuit.  Batteries with the capacity for higher electrolyte levels will help to ensure a longer battery life.

5.  Short Circuit:

Including causes such as:

• Plate to busbar short circuits can result from bent plates contacting the busbar, or corroded positive plates which have grown upwards, contacting the busbar and causing a short circuit.  This fault can be age related and can be a normal 'end of life' condition.  It can also be a result of overcharging, cycling or elevated operating temperatures.
• Plate to plate short circuits occur when positive and negative plates make contact causing short circuit, resulting in battery failure.  Vibration can cause the plates to wear or pierce the separator material leading to a short circuit.  Century Yuasa Batteries utilise strong Polyethylene Envelope separators which makes them less susceptible to this problem.

6.  Worn out or 'End of Life' conditions:

The normal 'end of life' condition in a battery is when one or more cells cease functioning due to the positive plate grid having oxidised (corroded) and finally collapsing. Operating temperatures have a definite effect on battery life, and high temperatures will accelerate these 'end of life' conditions.

 

How heat affects batteries

High temperatures can have a devastating effect on the life of lead-acid batteries.  While more batteries experience end-of-life failures in the colder months, the real damage is done when the batteries are operating at elevated temperatures.  The damaging heat is generated from two primary sources: -

• the ambient or environmental temperature, and
• the under bonnet temperatures of the vehicle

Modern vehicle manufacturers have within the past decade increased engine operating temperatures in an endeavour to reduce harmful exhaust emissions.   The result of these changes, combined with high environmental temperatures, are accelerating the damaging effects on battery life as outlined below.

The key point of temperature measurement is how hot the electrolyte (battery fluid) becomes due to the above primary sources of heat.   High temperatures can cause the following potentially damaging effects:

1. increased gassing and resultant water loss
2. increased grid corrosion / oxidation
3. overcharging, and potential plate failure
4. increased battery discharge capacity
5. increased self discharge rate

The operation of a lead-acid battery is a chemical process, and like all chemical processes, battery performance is temperature dependent.  The available capacity and maximum discharge current available, both fall at lower temperatures and increase at higher temperatures.  Capacity and discharge current at -20°C is approximately half that obtained at +20°C.

1.  Increased gassing and resultant water loss:

As battery temperatures increase, the rate of gassing and water loss in a battery is increased exponentially.  The lead alloy used in the plate grid construction also influences the rate of gassing of a battery.  As gassing continues over time, the electrolyte level drops below the top of the busbar and the top of the plate groups become exposed.  This leads to major grid corrosion and reduced battery life, which will be discussed in more detail shortly.   Because of gassing, batteries need to be topped up with water and topped up more regularly under der extreme operating conditions.

The key point here is that the greater the available volume of electrolyte above the busbars in a battery, the longer the probable battery service life before the risk of exposure of the plates.  This is a very important design issue for battery manufacturers.

2.  Increased grid corrosion / oxidation:

The operation of batteries at elevated temperatures will result in increased positive plate grid corrosion (oxidation), and in extreme cases can bring about oxidation of the busbars in the battery.   Positive grid corrosion is a normal 'end-of-life' failure mode of batteries which is greatly accelerated at elevated operating temperatures.

As mentioned previously, the failure of plate grids and busbars is further increased if the electrolyte level drops below the top of the busbar and the top of the plate groups due to gassing (water) losses.  In extreme cases, plate grids can expand and break at the top of the plate group, causing battery failure due to short circuits.

The volume (reservoir) of electrolyte above the plate group and busbar in a battery can provide improved operating life at high temperature as more electrolyte is available to cover gassing losses before the risk of exposure of the busbar.

3.  Overcharging and potential plate failure:

As the battery operating temperature increases, battery internal resistance decreases and the charge rate acceptance of the battery increases accordingly.   That is, as temperature increases, the charging voltage applied by the alternator to a battery must be reduced to avoid overcharging.  The following curve indicates the variation of voltage with temperature that should be applied to a lead-acid battery to adequate and correct charging.

At elevated under-bonnet temperatures, charging voltage control can be difficult and inadequate, resulting in extended overcharging and reduced battery life due to positive plate material degradation and loss, often accompanied by softening of the negative plate material.

Different rates of air ventilation and the position of the battery in the engine bay can lead to an internal material difference in alternator and electrolyte temperatures which increases the rate of overcharging the battery receives and the subsequent gassing.

4.  Increased battery discharge capacity:

At elevated temperatures, the discharge capacity of a battery is increased, and the ability to deliver higher cranking current is increased - as shown in the following graphs.  In practical terms, this is of no real advantage, except in the case of a worn or reduced capacity battery, which may still function adequately due to the elevated temperatures.

This masks the fact the battery is nearing its end-of-life and when the temperatures become colder and the engine requires higher cranking amps to turn over due to the engine oil becoming viscous, the battery ultimately fails suddenly.

5.  Increased self discharge rate:

All automotive lead-acid batteries slowly lose charge when not in service.  This is known as self-discharge.  The rate of self-discharge increases with increasing temperature.  The time batteries can be allowed to stand without recharging is reduced with increasing temperature of storage.  Batteries should be recharged when the Open Circuit Voltage (OCV) drops to 12.4 volts.