||09-22-09 08:31 AM
Amps is current flow. A milliamp is a thousandth of an amp. An amp hour is the ability to deliver an amp for one hour, and is a measure of the capacity of a battery.
If you have a light that draws half an amp (500 mA) then a 1000 mAH battery should run it for 2 hours. If the light draws 2 amps (2000 mA) then a 1000 mAH light should run it for 30 minutes.
Keep in mind also that all LiIon battery packs contain internal circuitry to limit the amount of current they'll deliver, because LiIons have very low internal resistance, meaning that if you ask a 1000 mAH pack to deliver 20 amps, it'll do it....then it'll likely overheat, boil, and catch fire or explode. Thus the protective circuitry.