Do you ever wonder about the units used to describe batteries for your electronic gear? mAh means Milli
Ampere per Hour. Does that help? Probably not, unless you are a scientist. Even if you don't have a clue as to what a milliamp is, you can still use these values to decide which battery to buy.
Most rechargeable batteries have a number followed by mAh. What this number tells you is how many milliamps your battery has - it's a measure of the batteries charging capacity. The higher the number, the greater the capacity, the longer you can use it before recharging. Of course, this is a measure of the battery when it is new. Over time, the maximum charge decreases.
If two batteries are the same type (i.e. both NiMH or both Lithium-ion), a higher capacity battery (a higher mAh) will provide longer usage in between charging. Knowing how many mAh you need to support how you use your device can help you evaluate your battery purchase.