I was out riding this weekend when my board spontaneously shut off around 50% battery. I took the board back to my shop and attempted to diagnose.
The battery reads 41v but the minute I put a load on the ESC, the voltage drops to around 14v and stays there until I unplug the battery from the ESC, at which point the voltage jumps back up to 41v.
Sounds like a bad solder joint to me. Something in your setup is bottlenecking the current draw. Can you meassure the voltage as close to the battery as you can when you plug it in into the ESC? (like before the BMS)
If voltage stays steady you got a problem somewhere along your power input. I sudgest inspecting solder and connector joints to find the culprit. Might be in the BMS like someone stated if its not a charge only BMS.
Multimeter leads are connected to the battery’s charge wires, which route through the BMS.
I stripped the battery down and inspected all nickel strip, solder joints, etc. and could not find any damage. I agree with @soketsu this looks like it’s caused by the BMS.
If it is the BMS, do I have to get a new one? Or is there another solution?