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HELP a noob pls- Replacing my burnt controller 60V

Posted: Dec 07 2019 2:12am
by Alex Filippidis
Hi all,

I am an enthusiastic noob and would love some help if u can.

Got a cheappie used citycoco knockoff trike for my NGO and within few days working, the controller is dead.
As I am on search of finding a replacement need some help.

The set up is the following
- 16s battery | 67.2V | 20Ah
- 500W motor which writes on it 24V
- The burnt controller writes 60V

The question is, do I get a 60V controller or what? How come and the motor is a 24V and does the controller does the step down/ voltage regulation?

Thank you all in advance for the time and consideration and all the help.

Re: HELP a noob pls- Replacing my burnt controller 60V

Posted: Dec 07 2019 3:48am
by John in CR
How do you know the controller is fried and not the motor or both, since a motor failure can fry a controller? Other culprits stopping your ride could be the throttle, the brake cutoff, or even a bad connection anywhere in the electrical pathways.

If you don't already have a basic multimeter and ebike tester, purchase those economical and essential items for any ebiker. They help diagnose problems, which is half the battle. To test a motor for problems, test the phases...first by disconnecting the 3 phase wires and shorting 2 together while turning the motor and then all 3 shorted. It should get harder to rotate with each. Then test the halls, which an ebike tester makes simple. A tester test phases too, as well a throttles and controllers.

Throttles are a common point of failure. Since they're cheap it's good to have a spare, so order one with the ebike tester.

Now to your main question of which controller to buy. You had a failure in the very early days of ownership, but we really know noting other than the stated voltage and capacity of the battery. The failure could be from a mismatch with the motor, a quality defect of the controller, physical damage (crash, water intrusion, etc.) misuse by the rider (too big a load, too many repeated takeoffs, etc). More details are needed about how the failure took place, and while BLDC motors can often take much higher than stated voltage, that's not always the case, so more details please about the motor itself.

Re: HELP a noob pls- Replacing my burnt controller 60V

Posted: Dec 07 2019 8:29am
by Alex Filippidis
Thanx a lot for all the points and the help.

I do have a multimeter and carry some knowledge on motor and measurements and such.
I already isolated the phases and measured them by turning the wheels hence I think the problem is not the motor itself.

I havent check the throttle part which is wont be a problem I believe to do so.

So what you propose is to test the throttle and get the tester which I will do asap.

What about the potential mismatch? The failure started after a sudden start with one person on it (some 75kilos). Right there was no movement to the motor and when pushed there was friction. As soon as disconnected the phases it was freely moving with no prob.

Thnx again a lot for your time and consideration. Much appreciated.

Re: HELP a noob pls- Replacing my burnt controller 60V

Posted: Dec 07 2019 11:43am
by Voltron
Drag that goes away when unplugged is usually on the way from the motor to the controller somewhere. If you're lucky, maybe the phase wires melted a little and are shorting, so if that is it sometimes the controller still works after fixing the wires. Next is maybe blown component in the controller... Harder to fix....

Do you know the phase wire and winding test for a motor? If you short two of the three phase wires together, the motor should suddenly get hard to turn, then you work thru all three combos, and if one doesn't make the motor hard to turn, then there's a shorted winding inside the motor.

Re: HELP a noob pls- Replacing my burnt controller 60V

Posted: Dec 07 2019 5:19pm
by Alex Filippidis
Will check it again.
Thnx for all the help!!

Re: HELP a noob pls- Replacing my burnt controller 60V

Posted: Dec 07 2019 10:13pm
by John in CR
The resistance to turning the wheel that goes away when the phase wires are disconnected from the controller is a sure sign of shorted mosfets in the controller. It quite commonly occurs during a takeoff when the controller is already hot from use, because takeoff is when phase currents are the highest. As long as the blown mosfet(s) didn't take out any of the surface mount components on the controller board, the repair could be as simple as replacing the high side mosfets on the phase that is shorted.

Ebike testers just make what can be usually be done with a multimeter much more simple. To test the throttle, you need to apply +5v to the throttle positive wire, the negative to ground, and measure the voltage on throttle sense wire as you turn the throttle, which will probably go from about 1V up to a max of about 4V. There's no need to mess with that now, since the evidence points directly to the controller being the problem.

Re: HELP a noob pls- Replacing my burnt controller 60V

Posted: Dec 08 2019 2:28am
by Alex Filippidis
What about the first question on choosing controller?
As i mention the set up is 60V for the 16s battery but the motor says 24V on its side.

Thanks again.

Re: HELP a noob pls- Replacing my burnt controller 60V

Posted: Dec 08 2019 3:36am
by Alex Filippidis
Just for sharing found also this cool vid on how to replace the mosfets so I ll check it and give it a try.

https://www.youtube.com/watch?v=lTssCn5YyTw

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