Charger blow out

[chelsealuttrall]

my motorcycle project was up on a jack while working on it. I left it to buy an item and wait for it mid-project. Things weren’t buttoned up, but I didn’t think anyone would mess with it in the couple days it would take to get my item in the mail.

While I was gone today, though, my husband lowered the jack to use it for other projects. (He says it wasn’t a rough drop, but I don’t know….he’s not a “light touch” kind of guy). When he did this a giant puff of smoke went up. He sent me a short video and it was obviously coming from my charger box. The charger switch was off, and not plugged in…though the charging cord was attached, the prongs were suspended and not touching anything. The charger battery connections were attached so that once I plugged in and switched on, it would charge. I have charged without incident previously.

My question: what would cause the charger to do this? I’ve attached the investigation pics below.

My capacitors are swollen up and look like they blew up, my coil looks overheated because whatever the covering for the wires is, it looks like it melted off and piled below it in a pile of goo. Then, the thing next to the coil is blackened and looks like it was the origin of the overheat. What is that and why did it?

 

[amberwolf]

Is there anything unusual about the connections between the charger and battery? Are they something that can be disconnected and reconnected easily by anyone? Could they be reversed in the process? Could the output have been pinched / cut into by something?

Capacitors blown like that have usually been reverse-connected or had a voltage exceeding their limit applied to them. Shorting them should not do that, so even if the charger was plugged into the wall and switched on, and say, the jack/lift scissoring down and cutting into the output cord, or the connections came undone and the ends shorted together, it shouldn't cause them to pop like that.

However, sometimes caps just fail due to internal defects (wrong electrolyte formula), and them being swollen isn't a result of the failure, but actually the *cause* of it. Or, they could have failed long before from the electrolyte problem, and this is totally unrelated to that.

There is smoke damage around the main transformer on the DC side (where those caps are); it looks like it came from parts bolted to the heatsink on the side of the charger closer to the caps. *that* kind of damage can certaily be caused by shorting the output, or reversing it.

The goop is just silicone used to secure the parts from vibration.

If you can still read the part numbers on the blown parts (on the heatsink), and can replace those and the capacitors, it might be fixable, but there could be damage not visible that either caused the failure or was caused during the failure that will keep it from working or re-cause the failure.


If the charger was connected to the battery at the time it failed, you should check the battery itself to be sure it's not damaged, and that it's BMS, fuses, etc, are all still working correctly. If the charger was shorted out (either internal failure or anything external) it could have taken out a fuse to the BMS, or if no fusing is done then the BMS charge FETs could be damaged if it's a separate-port BMS, and both charge and discharge FETs could be damaged if it's a common-port BMS.

 

[chelsealuttrall]

Okay, I’ll check battery and surroundings tomorrow. Thanks for the tips!

 

[chelsealuttrall]

Found it! It landed on a pretty dang hot wire when he lowered it. Sat right on it.

 

[amberwolf]

Which wire?