heres the battery I was using
http://www.hobbyking.com/hobbyking/s...idProduct=9166
fits in a PEQ-15 with enough room left to put a triggermaster in
Got 900rpm out of it with
double torque gears, you'd get significantly more rpm if you using high speed or standard ratio gears. The LiPo has the amperage to move those gears and run a higher torque motor too.