Took my board out for a ride after some successful in-garage tests, and about 30 meters into my ride the board stopped responding, and as I picked it up got a bit of smoke and sizzle coming out of my unity. I took it inside and there’s a part in front of the battery-connector-side hall sensor plug that’s got a hole burned in it. The DRV chip on the same side also has some blisters suggesting that it’s toast as well. Powering up the unit caused more smoke to come out of the first part.
Now this is likely 100% my fault, but I’d like to know which of my mistakes to avoid to not burn through any more of these controllers. In no particular order:
- Took the thing apart, i.e. removed the silicone cover but also the heatsinks. I’m pretty sure everything went back together correctly.
- Scratched a little hole in the conformal coating from the shunts to try and diagnose what turned out to be a software problem (reinstalling firmware fixed it).
- Installed VESC 5.3 beta firmware on the thing (ran through the full setup and everything seemed normal, with the possible exception that the default switching frequency was 25kHz and I left it there).
- Possibly engaged the handbrake feature at 10A while moving at a brisk walking pace (this feature should be disabled over 0.1 m/s but my math might be off).
- Set a battery current limit that might have made the batteries’ internal protection circuit kick in
Any insight into what the fried part does? This is totally my fault, right?