Quote Originally Posted by blazerbotics
Voltage is the problem, every heavyweight runs on at least 24volts (20 Nicad/Nimh Cells).
Easely enough replaced with 1 or 2 these pack. Saves a lot of weight, probably cheaper than 60 NiMH cells and accepted in heavies.

Other option is 4 of these.

I agree, it's a small drop in voltage, but nothing you can't solve with the right motor and gearratio. The few amps you'll draw more to compensate shouldn't make the problem.