I've got a z20b. It has burned through 4 controllers. I suspect the problem is not with the poor quality controllers. It's the motor. Here's what Andy told me about the hub motor:
"You have a 940 RPM motor (one of the few that was sent with last year's production); this motor is much faster and much more powerful and this has been the problem. The 4th generation controller is made to run up to 200 amps and should do the trick."
My last controller did, in fact, last longer. But it fried the first time I tried to accelerate up a hill.
My question is (for anyone who wants to help), if it IS the motor, how can I know for sure? Could the motor be "feeding back" current to the controller and burning it out? How can I measure the back feed? If I get another controller, should I invest in a Kelly controller? Or will I just burn that one out, too, and waste my money? Has anyone run into a problem like this?
Appreciate any help you can give. I'm an electronics novice.