Low Voltage Issue on TRex

We have built a tank using 2 Power Wheels motors and the TRex dual motor controller. The tank weighs 34 pounds. We are using a 6 channel Futaba 6EXP transmitter and receiver. We are using the BEC jumper on the controller to power the receiver. With a fully charged 12v 1.8ah Pb battery, things work great for about 10 minutes. Then very quickly the tank starts to stall. According to the LED status lights it appears that the controller is resetting. Our guess is that the Power Wheels motors are drawing quite a bit more than we thought. Does this sound like the problem? Should we use a better power source such as a 6v 4ah battery? Would a NiMH or NiCD battery be better than a Pb battery? We need the tank to run for at least 20 minutes. Or is the problem with the Futaba transmitter and receiver?




I think you should measure the current your motors draw. Your 10-minute run time is consistent with each motor drawing 5A, which is not all that much (and thus quite feasible), so you definitely need a bigger battery if you want longer run time. Lead-based batteries are usually cheapest, so I would go with that. I’m not sure how you’re getting to 6 V, 4 Ah being better than your existing unit, but if you use two of them, you could get close to the 20 minutes you want. I’d get something like a 12 V, 7 or 8 Ah unit that is common in alarm systems and can be bought for $20 or so.

- Jan