MP 5 controller smoked?

[Waldmeister]

Dear all -

I have been trying to figure what exactly caused my MP 5 to stop working. I was using a marine circuit breaker, unfortunately one of the power cables came loose and caused a spark when it was acidentally pushed against the cirucuit breaker. After having fixed the cables and removed the circuit breaker, the motor does not react to any twist on the throttle (all three power lights are on). I have tried a different throttle, so that couldn't be the problem. Unfortunately I can't establish a bluetooth connection with the device I had ordered ("GM" is visible in the app but no connection whatsoever possible - with the green light on the adapter frantically flashing). Did I smoke the controller? Hall Sensors? I have notived that if I provide power, the motor is rather hard to push, although it's not entirely stuck. If I cut energy supply I can push the bike easily. I'd be very grateful for a couple of thoughts by experienced members on this board.
Thanks so much in advance... 

[NR]

What voltage is your battery? The mp5 won't run if the battery setting is different than the battery voltage.
If possible try different voltages (24/36/48).

[Tommycat]

Three power lights on = full battery power.
Flashing Bluetooth adapter = 5vdc, but no communication?
Hard to push = shorted motor phase. 

I'd probably check to see if the board is flashing a trouble code... And looking around for evidence of damage while your there. Double checking phase and hall sensor wiring.





Regards,
T.C.

[Bikemad]

If the main power connection came loose during regenerative braking, it could have damaged the controller.

Hard to push = shorted motor phase. 

As it is only hard to push when power is applied, it sounds like a problem with the controller, not a physical short within the motor phase wires.

I suspect that two of the six MOSFETs will have failed in a short circuit state (one switched Positive on one phase and the second one switched Negative on another phase) :



This would result in the problem you described, as two of the three phase windings will be continually energised in one fixed polarity, because the two windings would be constantly powered in series through the two shorted MOSFETs while the battery is connected.

I'm guessing that the motor will start to get pretty warm if you leave the battery connected for too long, and you probably experience a much bigger spark than normal when you connect (and disconnect) the battery. 

Unfortunately, I think a replacement controller will be required in order to get your motor running again. 

Alan
 

[Waldmeister]

Hey thank you so much everybody for your help.

I ran the pie on 48V (using a 48V battery) and never messed with the settings, so I guess it is some more serious damage...

Alan's suspicions definitely match the symptoms. I notice a bigger spark than usual upon connecting the battery. Plus I was going downhill (probably using regen braking) when the cable was loose (should have soldered it in the first place  )  and shortly before the motor shut off.
I'll pull out the controller and check for further signs of damage tomorrow (the screws are rusty, I will have to drill them open first 

I do have some experience with general bike mechanics, however my electronic skills are very poor.... if I do have to change controller, can I simply follow Gary's instructions on how to do that on youtube (I think he's replacing a MP 3 controller) or are there any pitfalls when dealing with an MP5 (like different wiring etc.) ?

I'll get back to you on the bluetooth trouble once I have the controller replaced 

Again thank you very much for your much appreciated help. I always enjoy reading the forum!

Edit: from further reading I do understand now the wiring is different but rather simple (three plugs..?)...

[Bikemad]

There is just a single Hall Sensor connector and the three separate Phase wires to disconnect from the old controller inside the wheel.
If the replacement controller has the same connectors as the old controller, it is straightforward to swap from on controller to the other (once the controller has been removed) but make a note of the Yellow, Green and Blue Phase wire positions on the controller before you disconnect them to ensure they go back the same way. 

If the replacement controller has different connectors to the old controller, you will need to change the connections on the wires to match the new controller (I presume the new connectors will come with the replacement controller if they are needed). 

Hopefully, the Bluetooth problem will also be cured with the fitting of the replacement controller.



Alan