What's the real problem?

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Last seen: 7 years 11 months ago
Joined: Wednesday, July 18, 2007 - 10:49
Points: 81
What's the real problem?

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.


Scotty's picture
Last seen: 11 years 2 weeks ago
Joined: Wednesday, April 23, 2008 - 19:57
Points: 16
Re: What's the real problem?

I don't claim to be an expert, but it sounds to me like you have GOOD motor. The problem is your motor can use more current than your controller can supply and because the stock EVT controllers have no overcurrent protection, they burn out.

My understanding is the Kelly controllers have both overcurrent and overheat protection built in, so if they detect current or temperatures that exceed the design limits, the controller will self limit the output to prevent its destruction.

This is what I have gathered between talking to Andy and the people at Kelly.

If you continue to fry EVT controllers, I do believe the Kelly will solve the problem. The only trouble will be trying to get a pre-wired one from EVT. You can get one directly from Kelly and wire it up yourself, but a pre-wired version is obviously nicer.

I have yet to read about anyone burning out a Kelly.


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