What the hole, BeaMiS?! Why you make the fuck? 🧐

Okay, so I’m doing an autopsy on the Muirderer mini cruiser that I got from @gogomrrobot. I bought it knowing that it wasn’t working, and that possibly either the BMS or anti spark switch had failed. Upon opening it, everything seemed to look okay except for one little spot on the BMS heatsink. I’m guessing this wasn’t an intentional modification to increase current flow. :joy: So, does anyone know what, or how this may have happened? I’ve never seen a melted hole on a BMS before. I don’t see anywhere else or any other components that look burnt, but I’m assuming that this is not salvageable, right? I just want to understand what may have been the cause of death for the BMS, before I start clipping wires, and if it could have affected the switch or anything else connected to it.

20190420_145203 20190420_145347 20190420_134202

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I have no idea how you unfuck this thing you did.


WTF, did someone drip gallium on that or something?


@brenternet No idea. I’m trying to figure out how it gave up all of its fucks already, before I even had a chance to give any fucks of my own to it.

@b264 Could be, or maybe it was a drop off Satan’s sweat? Maybe it’s not even the problem?

Gogo probably left his soldering pen on and it melted right through

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Was there maybe a screw through there or some other conductive material? My guess is that a live wire has been rubbing on something, worn through the insulation and shorted on that spot.

What does the other side look like?

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It’s shorted

Ive done this before on this exact same bms

When B- is connected, the whole thing is basically ground. So touch the batt+ anywhere and BAM!


@thisguyhere Thanks for the confirmation. I guess this is just a paperweight now, but I was expecting that. Looked like the BMS had come loose in the enclosure, so a positive wire must have gotten rubbed through on the heatsink. I’ll look closer to see if there is a burned/melted wire I missed. When this happened to you, did any other components get damaged, or was it limited to the BMS?

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Dont think it damaged anything, in fact i think i kept using that bms for a while…it was wired for discharge too. And it kept the pack 100% balanced

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Oh, that’s great if it still should work. I’ll keep looking around for the reason why the board won’t turn on.

Exactly as @thisguyhere said. Its shorted out. One dark late booze filled night I soldered on an xt backwards and the result looked very similar. Mine was un-salvageable as was only one vesc strangely.