Powering simple motor controller 18v15 without USB


I’m using an Arduino to control the motor controller but the motor controller only works with the USB plugged in. When USB is not plugged in, LEDs don’t turn on and the board doesn’t respond to serial signals from the Arduino even though it is connected to a 7.2v battery pack. In section 4.1 of the user’s manual, it states that the board “can be powered either from USB using a USB A to mini-B cable or from a power supply, such as a battery pack, connected to the large VIN and GND pads.” Am I doing anything wrong or does the board simply needs to be plugged in?

Thanks for your help!


I am sorry you are having a problem with your Simple Motor Controller. Do you have a common ground between your Arduino and Simple Motor Controller? Could you post a picture of your setup showing all your connections?


Hi Grant,

Thanks for replying. I do have a common ground between my Arduino and the controller. Here’s a picture of my connection. I unplugged some of the wires so it’s not that messy.

I have two controllers and I actually didn’t try the other one before. I just did and it worked fine so I think there’s just something wrong with the first one.

Therefore, my new question is: is there a way to power the controller other than the large Vin/GND and USB? I see some jumpers near the RC section but from what I read I think those are supposed to power the RC receiver? Thanks for your help!

The jumpers near the RC inputs are for powering an RC receiver or potentiometer and are not for powering the Simple Motor Controller. Did the Simple Motor Controller ever work when powered from Vin? Could you try measuring the voltage of the 5V pin on the Simple Motor Controller when you are supplying it power through Vin?


The 5V near the RC inputs reads ~0.9V. I think this might actually be my fault. At the very beginning when I was powering the motor controller, I was using a cable that was incorrectly color labeled. So vin from the battery actually went into the ground of the controller. Fumes came out immediately, probably from carrying too much current. I unplugged the wires immediately but it wasn’t fast enough I guess.

The Simple Motor Controller you have does not have reverse voltage protections, so plugging the power in backwards damaged your board. You might be interested in the newer version of our Simple Motor Controller, it has reverse voltage protection.