Originally Posted by rustyus

In Layman's terms, a 1C charge rate will take approximately 1 hour to charge a battery.

Convert the mAh (milliamp hour) capacity number to an Ah (Amp hour) number...Just take the capacity of the pack in mAh, divide it by 1000 to get Ah, or just move the decimal point left twice. Your 6500mAh battery pack = 6.5Ah battery pack will (theoretically) discharge 6.5 amps in 1 hour, and will take 1 hour to charge at 6.5 amps. 1C charge rate = 1 hour . Approximately because of variables. To cut the charging time in half of a 1C charge rate, you would do a 2C charge rate. Charging your 6500mAh (6.5Ah) at a 2C rate...you would set your charger to 13 amps (6.5 x 2), and would take approximately 30 minutes to charge. This is assuming you have a charger with that much power.

Lot of good info here...http://www.rogershobbycenter.com/lipoguide/