The charge in batteries is typically measured in milliamp hours, or mAh for short. This is a measure of the amount of current and time that a battery can be expected to deliver. The higher the mAh rating, the longer a battery can be expected to last.
While this applies to non-rechargeable batteries as well, the higher price of rechargeable batteries will often times have people shopping for a bargain, without paying attention to how long the batteries can actually be expected to last.
Below are some mAh ratings taken from batteries that I have here. As you can see, there are some significant differences in the mAh ratings for these batteries.
EPT Battery 300 mAh
Energizer Recharge 700 mAh
Duracell Rechargeable 1000 mAh
Rayovac Rechargeable: (not listed on battery)
Energizer Recharge: 2300 mAh
Energizer Rechargeable: 2500 mAh
If you have some rechargable batteries, please check the mAh rating printed on the battery and feel free to post it, or any other comment, below.