What are the different types of battery chemistries/technologies?
Batteries in portable consumer devices (laptops and notebooks, camcorders, cell
phones, etc.) are principally made using Nickel Cadmium (NiCad), Nickel Metal Hydride
(NiMH), Lithium Ion (Li-Ion) or Lithium Polymer (Li-Pol) technologies. Each type
of rechargeable battery technology has its own unique characteristics:
Nickel Cadmium (NiCad) is the most popular type of rechargeable
battery, although it tends to suffer from "Memory Effect". It has a high rate of
energy discharge, meaning that it is low maintenance with high performance. Nickel
Cadmium can deliver even power until nearly all of the battery has been used.
Nickel Metal Hydride (NiMH) is the most advanced commercial rechargeable
battery. Nickel Metal Hydride batteries last 40% longer than Nickel Cadmium batteries.
This battery is generally much more environmentally friendly than Nickel Cadmium,
Lithium Ion (Li-Ion) is the newest batteries technologies, which
do not suffer from the "memory effect" at all. These batteries have twice the energy
of Nickel Metal Hydride, although they weigh 33% less. This is especially nice for
portable items, such as laptops, digital cameras and camcorders.
Lithium Polymer (Li-Pol) is basically the same technology as Li-Ion;
however the batter cells are constructed out of flat polymer sheets to make flat
batteries. This allows batteries to be placed in small places like behind laptop
screens. This technology is only used in limited laptop applications, however it
is used more widely in PDAs, tablet computers, and cell phones.
What is Capacity (mAh)?
The capacity of a battery is rated in mAh or Ah. If the capacity of a battery is
4400mAh (Milli-Amp Hour), it means that this battery can deliver 4400 mA (Milli-Amps)
of current for 1 hour at the rated voltage. The actual amount of current a notebook
draws depends on the usage. Things like LCD brightness, processor usage and hard
drive usage affects the amount of current required.
To convert mAh to Ah, divide by 1000. To convert Ah to mAh, multiply by 1000. 4400mAh
How are batteries rated? (What are Volts and Amps?)
There are two ratings on every battery: Volts and Amp-hours (AH). The AH rating
may also be given as milliamp-hours (mAH), which are one-thousandth of an amp-hour.
The voltage of the new battery should always match the voltage of your original.
Some of our batteries will have higher amp-hour ratings than the original battery
found in your device. This is indicative of a longer run-time (higher capacity)
and will not cause any incompatibilities.
Does the voltage of the battery need to match the voltage of the original battery?
While the voltage may not be identical to the original battery, the voltages must
be within a reasonable range. Historically some manufacturers picked 3.6V while
others picked 3.7V to name the cell. The functionality and performance of either
cell is identical and cannot be differentiated by the device.
The explanation above applies to a single Li-Ion cell in series. When a battery
has two or more Li-Ion cells in series, the voltage is multiplied by the number
of cells in series, as in the table below:
Number of Li-Ion cells in series
Type of device
3.6V or 3.7V
Cell phones and Digital cameras
7.2V or 7.4V
Digital cameras and Camcorders
10.8V or 11.1V
14.4V or 14.8V
A Li-Ion battery labeled 3.6V is the same as a Li-Ion battery labeled 3.7V.
A Li-Ion battery labeled 7.2V is the same as a Li-Ion battery labeled 7.4V.
A Li-Ion battery labeled 10.8V is the same as a Li-Ion battery labeled 11.1V.
A Li-Ion battery labeled 14.4V is the same as a Li-Ion battery labeled 14.8V.
How should I use and care for my rechargeable battery?
Your new battery comes in a discharged condition and must be charged before use
(refer to your computer 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 your computer may indicate that charging
is complete after just 10 or 15 minutes. This is a normal phenomenon with rechargeable
batteries. Simply remove the battery from the computer 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. To discharge, simply run your 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 your user's manual.
If the battery will not be in use for a month or longer, it is recommended that
fully charge the battery and removed from the device and stored in a cool, dry,
It is normal for a battery to become warm 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 BattDepot.com battery will often be higher
than the one on your original battery. A higher mAH rating is indicative of a longer
lasting (higher capacity) battery and will not cause any incompatibilities. An BattDepot.com
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, the use of the monitor, the hard drive and other
peripherals results in an additional drain upon the battery, effectively is 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 your computer's power management features. Refer to your computer manual
for further instructions.
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 continually only partially
discharged before re-charging, 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. Your 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) your battery at least once every two to three weeks. Batteries
can be discharged by unplugging the device's AC adaptor and letting the device run
on the battery until it ceases to function. This will insure your battery remains
Can I upgrade my current battery to a newer chemistry?
NiCad, NiMH and Li-ion are all fundamentally different from one another and cannot
be substituted unless the device has been pre-configured from the factory to accept
more than one type of rechargeable battery. The difference between them stems from
the fact that each type requires a different charging pattern to be properly recharged.
Therefore, the portable device's charger must be properly configured to handle a
given type of rechargeable battery.
Refer to your owner's manual to find out which rechargeable battery types your particular
device supports, or simply use our search engine to find your device. It will automatically
list all of the battery types supported by your machine.
If my computer came with a NiMH battery, can I change to a Li-ion?
The different battery chemistries have different electrical properties and need
to be charged differently. The charging circuit in the computer must be designed
and calibrated to match the chemistry of the battery. So if your computer's charging
circuit was designed for NiMH, you cannot change to a different battery type.
The exception to this rule is many computers that were produced when the industry
was changing from NiMH to Li-Ion technology. Manufacturers designed many models
sold during this transition period (around 1997-1998) to work with either type of
battery. If we list both a NiMh and Li-Ion battery for your computer model then
it can support either battery type. If we list only one type of battery for your
computer, it most likely will only support one type; however you can check with
your computer's manufacturer for a definite answer.
How long do batteries last (What is the life span of a new battery)?
The life of a rechargeable battery operating under normal conditions is generally
between 300 to 400 charge-discharge cycles. This translates into one and a half
to two years of battery life for the average user. As your rechargeable battery
begins to die, you will notice a decline in the running time of the battery. When
your two hour battery is only supplying you with an hour's worth of use, it's time
for a new one.
My New Battery isn't Charging?
New batteries are shipped in a discharged or low capacity condition. We generally
recommend a fully charging the first time using. Refer to your user's manual for
charging instructions. Rechargeable batteries should be cycled - fully charged and
then fully discharged - 2 to 4 times initially to allow them to reach their full
capacity. (Note: it is perfectly normal for a battery to become warm to the touch
during charging and discharging).
New batteries are hard for your device to charge; they have never been fully charged
and are therefore "unformed". Sometimes your device's charger will stop charging
a new battery before it is fully charged. If this happens, simply remove the battery
from your device and then re-insert it. The charge cycle should begin again. This
may happen several times during your first battery charge. Don't worry; it's perfectly
I just bought a new battery, what should I do first?
New batteries are shipped in a discharged or low capacity condition. We generally
recommend a fully charge. Refer to your user's manual for charging instructions.
Rechargeable batteries should be cycled - fully charged and then fully discharged
- 2 to 4 times initially to allow them to reach their full capacity. (Note: it is
perfectly normal for a battery to become warm to the touch during charging and discharging).
I find a battery matching my original battery's part number, but my laptop model
number is not in your list, What should I do?
Our batteries and battery chargers are generic replacement; some batteries are compatible
to lots of laptop models. It is not possible for us to collect and post all the
model numbers at one time. If you can match our listed compatible OEM part number
and picture with your original battery, we guarantee the battery or charger 100%
meet or exceed the OEM specifications; you will have 1 year warranty for it upon
My charger shows that my battery is fully charged, but it is not working... Why?
This is known as "False Peak" and is very common condition during first time battery
use (or using a battery that has been discharged for several months). The charger
light may go out after only five or ten minutes, indicating that it is fully charged
when it is not. Should this happen, simply leave the battery on the charger for
about an hour. Remove it, and return it to the charger immediately. The battery
will resume normal charging and the charger light will indicate when the battery
is ready for use.
What is the run time of the battery?
Battery run-time on a laptop is difficult to determine. Actual battery run time
depends upon the power demands made by the equipment. The use of the screen, the
hard drive and other accessories which results in an additional drain upon the battery,
effectively reducing its run time. The total run-time of the battery is also dependent
upon the design of the equipment. Generally, a new battery will run 30% to 50% longer
than the old battery did when it was new.
How Can I Maximize Battery Performance?
There are several steps you can take to insure that you get maximum performance
from your battery:
Breaking 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 your new battery two to four times to allow it to reach its
maximum rated capacity.
Preventing the Memory Effect - Keep your 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.
Keep Your Batteries Clean - 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 your portable device.
Exercise Your Battery - Do not leave your 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 your battery,
fully optimize the notebook's 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. Your notebook
user's guide will provide information relating to specific power management features.
What are Main Batteries?
The main battery (also called the power battery) is the battery pack which allows
a laptop or notebook to operate independently of an AC power source. These rechargeable
batteries are designed to operate the computer for a certain amount of time (generally
1 to 4 hours).
What are "RAM" or "Resume" batteries?
Some notebook computers are designed with a dedicated battery for backing up RAM
functions when the machine is temporarily shut off. This feature allows users to
change the main battery pack without losing the current applications and settings
residing in RAM (Random Access Memory). This is called a "battery hot swap" - switching
the main battery pack without having to turn off the computer.
These types of batteries are alternately known as bridge batteries, RAM batteries,
or resume batteries.
Most RAM batteries are rechargeable NiCad and will last around 2-3 years. It is
recommended that you replace your notebook's RAM battery when replacing the CMOS
What is a "Smart" Battery?
Smart batteries have internal circuit boards with smart chips which allow them to
communicate with the notebook and thus better monitor battery performance, output
voltage and temperature. Smart batteries will generally run 15% longer due to their
increased efficiency and also give the computer much more accurate "fuel gauge"
capabilities to determine how much battery running time is left before the next
recharge is required.
What is a refurbished battery?
Refurbished batteries are used batteries. Some laptop battery vendors offer refurbished
discount laptop batteries for sale, claiming that most or all of the useful life
of the laptop battery has been restored. Why would customers take the risk? Refurbished
items are generally cheap laptop batteries that are sold at a fraction of the cost
of a new laptop battery.
Unfortunately, their true worth is essentially zero. The reality is that refurbished,
cheap laptop batteries don't exist. Though technically possible, the process of
refurbishing a laptop battery costs more than manufacturing a new one. The internal
impedance of each lithium ion cell in a laptop battery pack must be matched precisely,
and there are only a few manufacturers have the technical expertise required. By
the time a skilled technician disassembles, tests, and reassembles a laptop battery,
the cost is prohibitive.
So what are these so-called "refurbished" discount laptop batteries? They're simply
used laptop batteries that have been pulled from older laptops. The problem with
old, cheap laptop batteries is that you don't know how much life they have left.
All Lithium ion cells offer a maximum of 500 to 800 charge/discharge cycles over
1 to 3 years of useful life. It's impossible to know how many cycles - and months
- have passed since a particular used laptop battery was built, but one should probably
assume the worst. In fact, that's just what the sellers of refurbished, cheap laptop
batteries do - they generally warranty their discount laptop batteries for just
My Battery is dead, how should I recycle it?
Nicad, NiMH, Li-Ion and Li-Pol batteries should be recycled. Be environmentally
conscious - DO NOT throw these batteries in the trash.
If you don't know where your local recycling facility is, call the Portable Rechargeable
Battery Association at 1-800-822-8837. They will provide you with the address of
the recycling center nearest to you.