Need help troubleshooting 72v 2000w controller/motor please

First I want to thank you for providing this forum, it has been a great help to me to learn the basics of electric scooters.

I purchased a 2000w 72v electric scooter about a year ago. It's a chinese scooter and has performed well until I had a flat rear tire and had to remove the rear wheel that also contains the hub motor. To make a stressful long story short, when I was reattaching everything I neglected to turn off the circuit breaker and mistakenly bumped the yellow motor wire (pic, bottom right) in between the red and black wires on the block. This resulted in a loud pop and spark and now the motor no longer runs when the throttle is twisted.
I tried for 2 weeks to obtain a wiring diagram from the online dealer to help to troubleshoot the scooter without success. I'm not sure if the motor is damaged, or the controller. My dealer wants $350.00 just for a controller. The lights, horn, signals still work. I have kept the batteries charged every 5-7 days.

Any help anyone might give would be greatly appreciated. I am without a car right now and I depend on the scooter to get to work 5 days a week. Thank you so much!

First, you do not actually have the green wire connected yet; it's not bolted down liek the others are. I'd recommend fixing that first before doing anything else, then retesting.

Also, the yellow and blue wires do not appear to be tightened down fully, assumign their bolt lengths are the same as the red and black. If they have shorter bolts then they may already be tight.


I don't see any damage or burns on the yellow wire, or the red and black wires' nuts, bolts, or wires, so it's unlikely anything there is physically damaged by a short.

Next, without knowing for sure where each of those wires goes, and what voltages would be on each one under the conditions at the time it happened, I coudln't say for sure what failed.

But the most likely would be the controller, assuming:
--red is battery positive and black is battery negative
--yellow wire is one of the three phases and
--green and blue are also phases and
--one or both were connected already to the controller and
--were at a different voltage than whichever other wire the yellow touched

if the above is all true then it's possible one or more FETs or sets of FETs in the controller were damaged (this damage may be visible or not, if you were to open up the controller, but can be tested for even without opening it via the instructions at http://www.ebikes.ca/learn/troubleshooting.html ).


Another possiblity is that if:
-- the yellow wire actually shorted *between* the red and black
and
-- red and black are battery positive and negative

it could just have blown a fuse or popped a circuit breaker. This you can test for by measuring for voltage between the red and black. If there is no voltage, then that's what happened. You can then physically follow the wires from there back to teh battery and draw up your own diagram of what connects to where, and locate any fuses or breakers along the way.

Thanks for the reply Amberwolf. Yes the red and black wires go to the batteries and the green, blue and yellow go to the hub motor. There is a circuit breaker next to the charging port and it did pop off when the spark happened. I just don't have a lot of money so just want be sure to order the right thing. I'm including the "after" damage pics and a pic of the whole block. Thanks very much!