If you run the gear to the mechanical stop on a battery w/o the controller, the gear motor will burn out. There are current limiters in the controller. If you use too high of a voltage, the gear motors may also burn out. The JP controller I had did have a voltage regulator in it. I ended up junking that controller cause I could never get the brakes working correctly. I replaced the JP with the LGC 15 and had to add a voltage regulator because I use 2S LiPos and the gear motors apparently can't take 2S LiPo voltages..