What does “mAh” mean?
A measure of a battery's total capacity. The higher the number (ex. 600 mAh, 1,500 mAh) the more charge a battery can hold and usually, the longer a battery will last under a certain load.

What is Memory Effect?
 Ni-Cad batteries suffer from what's called the "memory effect" This means that if a battery is continually only partially discharged before re-charging, the battery "forgets" that is 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 it's 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 month. 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 ensure your battery remains healthy. Ni-Mh and Li-Ion batteries do not suffer the memory effect.

What are battery ratings?
There are two ratings on every battery: Volts and Milliamp-hour (mAh). The voltage of the new battery should always match the voltage of your original. Some of our batteries will have higher amp-hour ratings that the original battery found in your device. This is indicative of a longer run-time (high capacity) and will not cause any incompatibilities.

My New Battery Isn't Charging, what's going on?  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 your user's manual for charging instruction. Rechargeable batteries should be 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 because 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 start again. This may happen several times during your first battery charge. Don't worry; it's perfectly normal.
How can I maximize battery performance? 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. 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 laptop. 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 do not plan on using the battery for a month or more, we recommend storing in a clean, dry, cool place away from heat and metal objects.

What are the types of batteries?

Li-ion = Lithium Ion, The latest type of rechargeable battery. Lighter in weight and can offer higher capacities over NiMH. Supplied as standard in most new laptops and notebooks. These can only be used in laptops that are designed for them.

NiCd = Nickel Cadmium, older type of rechargeable battery. Loses it's capacity to hold a charge if not fully discharged then recharged regularly, this is also known as the memory effect.

NiMH = Nickel Metal Hydride, a newer type of rechargeable battery. Offers higher capacities and improved performance over NiCd. Less prone to the memory effect than NiCd, but can still suffer if not discharged then recharged correctly.

RTC = Real Time Clock, a small battery that keeps the computers clock running even when the main battery is removed

Resume = Resume battery, powers the laptop whilst it goes into stand by mode to allow the main battery to be removed and replaced without losing data.

2nd bay battery = Fits in the bay of a laptop normally where the floppy drive or CD/DVD lives. Gives you more mobile power capacity providing you don't need to use the floppy/CD/DVD.