The C-Rating of the battery defines the maximum draw (in amps) that the battery is capable of. To calculate the max amp draw you need the C-Rating and the mAh of the battery. For example a 2000 mAh battery rated at 10C would be:
Max Amp Draw = (mAh / 1000) * C-Rating
(2000 / 1000) * 10 = 20 Amp Max Draw
Note: Running your batteries at their C-Rating will decrease the overall life of the battery.
The C-Rating also indicates the amount of time the battery can support that discharge rate. A 1 C battery can support the calculated draw continuously for 1 hour. 2 C would be 1/2 of an hour. 10C would be 1/10 of an hour.

