Replacing or repairing controller

[Keldin]

I have a Mezzo folding bike that's been converted to electric and it has developed a fault.
It's new and only been ridden a few times but now the battery level on the LCD display shows no power (battery level empty) although the LCD display powers on including backlight.
The throttle produces nothing from the motor and pedal assist get's no joy either.

So far I have replaced the battery even though the original tests and charges OK as well as the display with no change.
The only thing left would be the controller or the motor or the wiring.
Unfortunately a replacement controller has proven hard to get so now I'm looking to either repair or replace it with an alternative of some form.
Does anyone know what I could replace it with or how I could diagnose if the controller is even at fault? Replacing seems difficult as it only has a few waterproof connectors (PAS, motor and wiring harness plus battery) and nothing available seems to have the same wiring.
I've attached some pics if that helps.
I'm in SW London/Surrey if anyone knows of a place nearby with some technical expertise.
Thanks
David

 

[Deleted member 4366]

That's a Kunteng controller. The waterproof connectors make fault-finding really difficult, even if you knew the pin-outs.The S06S (also Kunteng) from BMSBattery is similar, but with different connectors. The throttle and Pedal sensor don't cost much, So you could replace everything except the battery and the motor, which would be about £60 including shipping. The motor connector is different, so you'd need to cut the connector off your present controller and join the wires to the new one.Also, unless your controller and connectors are located in a compartment, you'd need to cover the connectors somehow.

If you're handy with a voltmeter and screwdriver, you should be able to find out what's wrong with your controller, or you might be able to bypass something to get it working. For that, you need to take the controller out of its case to get to the ends of the wires, which means undo the 4 screws in the wires end and the three in the side. You might have to take the other end off too if it uses plates to hold the FETs against the sides.The main battery wires come in and go straight to the motor, but are blocked. The a thin wire is taken from the positive to power the panel. When the panel is switched on, it activates a positive return to the controller that powers it. It could be that it's not being activated. There's probably a flashing LED in there that tells you when it's activated, otherwise you can measure with the voltmeter. If you want to do the tests, but are still unsure what to do, take some good photos of both sides of the controller's circuit board.

One other thing, just to eliminate it. Some of these controllers are dual voltage 36v/48v or 24v/36v. I've heard of one that got confused between a flat 48v battery and a charged 36v one because it can only guess from the voltage it sees. If you can try it with a half-charged battery, it should make its decision easier.

 

[Keldin]

Thanks for the detailed reply.
I've managed to get some life out of it now but that's just left me a little more confused. I connected everything up with the exception of the PAS cable and the battery indicator now shows full with the throttle able to drive the motor.
Connect the PAS up and it immediately drops the battery gauge down to empty and the throttle gets no response from the motor.
I would have thought that a faulty PAS would just mean the pedal assist wouldn't work. I'm going to try and get a replacement for the PAS and see if that resolves it. If not I suppose there may be something PAS related in the controller that is malfunctioning when it's connected.
I'll swap the PAS out and update once I know more.
Thanks again.

 

[Deleted member 4366]

If there were a short in the PAS, it would take down the whole 5v rail, which also powers the CPU, so that's probably it. You should be able to use any PAS and swap over tge connectos, unless the dhort is in the connector. Does the wire look damaged at all? The other thing that happens is when there's no gap between the sensor snd the magnet disc, so the disc grinds awsy the sensor until it's ruined.

 

[Keldin]

There's no sign of any damage so possibly a short inside the sensor or in the cable somewhere. Having some trouble finding a replacement with the same connector and swapping over the connector is not possible as its a sealed plug rather than something that can be opened and connected to bare wires. All the PAS cables available seem to end in a square type plug that doesn't look very water resistant. May have to give up and splice the wires with some heat shrink tubing for protection if that's all that's available.
Thanks

 

[Deleted member 4366]

I think Oxygen have the same connector and they have a big bag of spare sensors, but they're handed and nobody can tell if they're left or right handed. If you have space on both sides of the crank, it won't matter. Also, all the guys that bought the Oxydrive kits after Xmas should have a spare sensor because two different ones were provided in their kits. Perhaps one of them could confirm that the connector is the same and maybe make you an offer.

 

[Keldin]

It's all fixed now. It was the PAS in the end. It must have been shorting out as you said. The wires had a fair amount of bare wire and a little silicon to waterpoof but not enough to hold them apart. Redid the connection and it's all working now. I'll get a replacement when I can find one but no rush now.
Thanks for the help.