I have a generic 72v controller, which yesterday suddenly started making loud pops and crackles so I shut it down unplugged battery and walked home. I opened it up and I found that two neighbouring mosfets had shorted somehow, drain leg, to source leg of the other I believe but I'll double check if it matters. Hat area would emit a yellow orange glow which increased and grew to loud pops if throttle kept increasing. Cleaned up the area with rubbing alcohol , reflowed the solder which was actually shorting the two legs, and found a chunk of the PCB has beeb charred and its like a small crater between two traces but the traces are intact. The glow comes from this crater. I cleaned with alcohol again and tested. The glow was much smaller, and as I held down the throttle about 10% it went away entirely. I was able to go WOT with no load and held it for about 10 seconds and it all looked good. So I covered that area with liquid electrical tape in a thin layer. It dried overnight. I go to try it again just this morning and I see smoke and glowing again , finally popping like before.. replace controller? I'd like to salvage if possible ... Did my electrical tape frozzle it?
Generic controller sparking at mosfets when applying throttle.
- Thread starter 5kr3wf4c3
- Start date
If the FETs aren't blown and it was just a bad solder joint, it should work OK. I would recommend cleaning up the area, scrape off some of the green solder mask on the trace, then solder a piece of copper wire around the FET leg and onto the trace to make sure you have enough copper and good conductivity.
The original problem was most likely a bad solder joint that started arcing and overheated.
The original problem was most likely a bad solder joint that started arcing and overheated.
A picture would be cool.
It's possible it was just a really bad soldering job from the factory and a little blob of solder shorted between the traces. Once you get an arc started, it's like a little arc welder and will burn away anything in it's path.
It's possible it was just a really bad soldering job from the factory and a little blob of solder shorted between the traces. Once you get an arc started, it's like a little arc welder and will burn away anything in it's path.
