What is Ah?
Ah (Ampere hour) is a capacity rating that measures how much current a battery will discharge over a specified period of time (generally a 20 hour period). Higher mAh ratings do not necessarily reflect how fast current can be drawn, rather, how long a current can be drawn. For example a 20Ah battery will sustain a 1-amp draw for approximately 20 hours before dropping to a voltage level that is considered discharged. A 40Ah battery will sustain an 8-Amp draw for approximately five hours. Overall capacity will be influenced by other factors including temperature, depth of discharge and speed of charge/discharge.
