Destroyed Pololu 36v20 CS

I am in the process of building an RC Lawnmower which incorporates an Arduino Mini Pro, Xbee and 2 Pololu 36v20 motor Drivers. I somehow managed to destroy the Arduino and the two motor drivers when I hooked my circuit up to 24 V. As soon as I turned the main power switch on a saw a spark and the Arduino lights were glowing dimly. Arduino will no longer respond to the computer and the motor drivers are dead.

Link to motor driver here: Pololu High-Power Motor Driver 36v20 CS

I had issues soldering the capacitors in there intended places so I decided to use the GND and V+ pins on the the logic side of the board to place the decoupling capacitors :blush:.....................I have a feeling this is what destroyed them, can anyone confirm?

Any ideas? I also had an electrolytic capacitor in wired in reverse by accident.

mech_eng:
Any ideas? I also had an electrolytic capacitor in wired in reverse by accident.

Well, that certainly didn't help things.

Considering you made that mistake - without seeing your actual wiring, etc - how are we to be able to diagnose any other potential mistakes you made?

You might try removing the blown capacitor to see if the rest will work.

I’ve doubled and tripled check the rest of the wiring and have removed the capacitor with no luck. I also continuity tested power and ground before hooking up power to ensure no shorts…I can’t seem to figure out what went wrong if its not the pins I hooked the caps or the cap the I wired in reverse.

The power source is two 12V batteries in series and this did not do any visible damage to the 470uf cap wired in reverse, makes me wonder if a trace was blown in the transient process after power was hooked up?

Also, when I cut the wires from the motor drivers to the Arduino (PWM and digital for direction) the onboard LED glowed as they should. I then put an amp meter between the output of the Arduino to the input of the motor driver as was pulling 90mA which is obviously what damaged the Arduino.

The motor driver PWMH and DIR pins seem to be shorted to ground (not from my wiring however)

Final bump

Show us some pictures on how you connect up the Arduino, Pololu 36v20 motor Drivers, battery and the motors.