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Flipsky 75/100 Mosfet short?

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Michael Campbell
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Flipsky 75/100 Mosfet short?

Hi All.

I have bought a flipsky 75100 VESC to replace the original controller on a Xiaomi M365 pro scooter. 

While testing the controller, I had been having trouble with it cutting out under load. It would start off smoothly, but then suddenly cut out at a certain speed when accelerating. 

I played around with current settings to see if I could make it better/worse. Now though it has died completely, with the following symptoms:

-Motor is difficult to turn by hand, even when battery is unplugged. Unplugging the green motor lead makes it spin smoothly.

-Plugging into the battery, the VESC will power up, the motor will shudder for a moment, then it will turn off. It will then turn back on again, do it one more time, and then stay off.

-if you plug the VESC into the battery with no motor connected, it will still power up but then immediately switch off again.

-The battery itself seems to be going into some kind of protective mode as well after plugging in.

To me this seems like a phase short in the controller, but I can't see anything obviously wrong when I open it. The solder is all in the right place, and nothing smells or looks burned.

I will add that my battery current and motor current were at 35/75A respectively which should be fine for this controller.

Can anyone suggest what might have broken, and whether it can be fixed?

Thanks.

 

frank
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Probably a damaged power stage, shorted Mosfets or damaged gate drivers. The cause could be a voltage or current spike or a damaged motor winding or wrong settings.

These units can not be operated with the standard settings since they don't have phase filters. If you don't switch them off in the software, you can fry these units easily. I think Flipsky realized this and has a warning on the Website.

Michael Campbell
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Hi Frank 

I did see that instruction and made sure I turned phase filtering off.

Other than that I tried my best to follow the same settings that flipsky themselves use in a video guide where they install the same controller in a very similar scooter.

If it was the battery BMS causing the current to the controller to suddenly be cut, could the controller have been damaged? I.e. if the power was suddenly cut at speed and the motor was still spinning fast.

 

 

 

 

frank
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Yes that can destroy the unit. Typically it happens when the BMS disconnects and you regen current using the brakes. In that case the engergy has no way to be stored in the battery and you get big voltage spikes. This typically kills the logic stage and then switching the FETs is not possible any longer and from there things go really south in a bad way.

Michael Campbell
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Thanks, I bet that is what happened...Guess im ordering a new controller! damn it.