Error fault_code_under_voltage & Weak Breaks

I’m experiencing some issues with a DIY eSkate that I built.

It is a dual setup with 6355 Maytech’s motors, Focbox and a 10s3p Samsung 25R battery pack with Bestech BMS for charging & discharge and an anti-spark switch… few days ago the battery started to act weird, it dropped voltages from about 39v to 32v in the middle of the ride. I opened the battery and found out that few nickel strips got disconnected from some 18650 cells so I re-soldered them with my DIY spot welder.

Now the battery shows the correct voltage, however I’m facing some two serious issues:

  1. The brakes became very very very weak, I can barely stop the board completely even at low speeds ride. However acceleration and top speed are still fine and I don’t feel any difference.

  2. When I climb a hill or accelerate hard, sometimes the whole system shuts it self down. If I turn the board off and on everything is fine until I’m repeating the hard acceleration/going up a hill. I was connected to the Xmatic app to record the ride, when the board got turned off I received an error “fault_code_under_voltage”.

At this point I’m not sure if the battery is the problem, the BMS (due to it also discharge my battery) or the anti-spark switch.

If anyone have any idea what could be the source for this problem I’ll very appreciate it. :beers:

maybe try to ask here https://forum./