MP5 - sudden power shutdown while driving

[Spajder]

Greetings. New here. Frontwheel MagicPie 5 with (48V 10Ah lifePo4) in Slovenia 
My MP5 has been running without problems for about 1,5 years now (that is almost 1500 km).

This morning, as always, I was riding with my bike to work. Well, it didn't end very well.
After 200 meters, when I was driving at full speed (aprox. 26 km/h and all three battery gauge LEDs were on),
all three battery LEDs started to flicker and the motor started with regenerative braking.
In seconds I was without power, LEDs were turned off and the wheel almost locked (it was very stiff when I was pushing the bike back home - like regenerative brake had stayed turned on). There was no loud bang, arcing sound, blown fuse, sparks, hot wires, smoke or a burning smell - nothing. Turning the key in battery still produces a click at ON position, but battery gauge LEDs do not turn on and motor still remains stiff - no reaction.

My battery was at my working place previous day fully charged and after that I was driving my bike at least 5 km with no problems.

So, what should I do now? Is the motor intact or dead? What could cause such a behaviour and how to prevent it in the future? I can not do any diagnostics with any Bluetooth app, because it crashes constantly.

Thank you,

Vladimir

[Bikemad]

Hi Vladimir andto the forum.

Unfortunately, from your description, it would appear that the controller has definitely failed and will need to be replaced, but I don't know what has caused it to fail.

When you remove the controller, check for signs of water inside the controller housing. If water has managed to get inside, it is possible that the water could have caused the controller to fail.

However, if everything is still nice and dry inside, then the controller may have simply failed because of a weak component that has suddenly stopped working correctly.

The resistance to turning the wheel (even with the battery turned off) is usually caused by one or more of the MOSFETS shorting out internally, which in turn shorts out the phase wires and stator windings, causing the electromagnetic dynamic braking effect.

I suspect that the battery gauge LEDs are no longer lighting up because the short circuit in the controller is overloading the battery, forcing the battery's BMS to immediately cut the power as soon as the battery is turned on.

Alan