Controller (VESC) problems after reversing battery polarity

dapeba0210

Just Joined
Dec 1, 2024
4
0
Hello everyone,

I have a 20" folding bike that I electrified. The controller is a flipsky 75100, the motor is a mac 8T, and the battery is 14s4p.

The other day, I took the bike to a store to replace the battery. They were wrong, and in the new battery they reversed the polarity of the cables. So, when connecting it, the connectors burned. These were later repaired. Once repaired, I tested the bike and my surprise was that the controller is cutting off the current when it reaches 30-32 A. In addition, the motor temperature is incorrect, as it reads -70 degrees, and the speed it shows is also incorrect. It happens the same with the old battery.

Here is a video of the RT Data of the VESC controller in operation: VESC problems. - YouTube
Here is a video of the general configuration of my Flipsky controller (VESC). VESC configuration (youtube.com)

What could be happening? Before replacing the battery, with the same configuration, everything was perfect.

Thanks!!
 

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saneagle

Esteemed Pedelecer
Oct 10, 2010
6,893
3,193
Telford
When you connect a battery the wrong way round, it's effectively a dead short. It normally causes the shunt or tracks on the pcb to blow, and it will also damage the main capacitor, which will blow completely if connected for any length of time.

If it has a wire shunt, the solder joints could be compromised, and if it has solid state ones, anything can happen. Either way, the result would be that the current flowing would be misreported to the controller, so whatever you see on any display would be incorrect and any control of the current would also be incorrect.

I can't see how reversing the batterycan affect the speed calculation or temperature measurement, but anything is possible due to the amount of trauma the controller suffers from such an event.
 

Sturmey

Esteemed Pedelecer
Jan 26, 2018
645
354
68
Ireland
......... In addition, the motor temperature is incorrect, as it reads -70 degrees, and the speed it shows is also incorrect. It happens the same with the old battery........
Combined Speed/Thermistor: All the G31x motors at Grin now have a dual speed/temperature signal on the extra white wire, rather than just a simple speed sensor.
I wonder is your motor similar to Grin's where the white wire is used for both the speed and temperature sensor?
 

dapeba0210

Just Joined
Dec 1, 2024
4
0
When you connect a battery the wrong way round, it's effectively a dead short. It normally causes the shunt or tracks on the pcb to blow, and it will also damage the main capacitor, which will blow completely if connected for any length of time.

If it has a wire shunt, the solder joints could be compromised, and if it has solid state ones, anything can happen. Either way, the result would be that the current flowing would be misreported to the controller, so whatever you see on any display would be incorrect and any control of the current would also be incorrect.

I can't see how reversing the batterycan affect the speed calculation or temperature measurement, but anything is possible due to the amount of trauma the controller suffers from such an event.
Thanks for the answer, I have just bought the new flipsky v2 controller...After testing I will check if the temperature and speed has been fixed...