Originally Posted by Nigel Goodwin

If these are R/C model motors (as used in Tamiya R/C car models?), then the stall current is likely to be far greater than 20 amps - a LOT depends on your power source, which 'may' be the limiting factor?. NiCd batteries have very low internal resistances, and can provide enough current to destroy themselves - which is what makes them fairly dangerous.

Originally Posted by pike

Listen to this guy. 20 amps is too small for a stall current from something like a traxxas emaxx. If its got a mabuchi rs-550 (a common choice in a monster truck of that model) your looking at 70-80 amps!!

here: http://www.mabuchi-motor.co.jp/cgi-b..._ID=rs_550pcvc

If it has the red dot on the back of the motor, you know what you have...a mabuchi 550.