Smokey The VESC -- Unsure cause

I know all that. The difference is that the spark is contained between the female and male sides of the connector but always on the same polarity. On an XT the arc can also jump to the other polarity connector on the male side. It does not cause any major problems but it can wear down the connectors a lot faster.

I’d be more suspicious about this rather than attribute it solely to a capacitor charging spark.

I had something very similar happen to an old vesc. Plugged it into a 6S battery once after a long time, big spark, I left it plugged in, and the thin alligator clips I used to connect it started smoking.

I hooked it up to a bench power supply and slowly turned the voltage up. It drew ~3 or 4 amps continuously at 5V. That was not the capacitors charging, something had been shorted.

@Lanik If you have a power supply I suggest hooking it up to that and seeing what kind of power it’s drawing before you continue. Use low voltage and just read current. There’s no use in frying more connectors (or even possibly an antispark switch) if the vesc is toast.

Idling a vesc shouldn’t draw very much power once the caps are charged.



Yes; the charging should happen in less than 1 second. After that, you should have <100mA draw


Actually further inspecting the connector, those positive leads are seriously melted. You don’t vaporize significant amounts of metal like that from charging up some measley caps.

The tip of the female positive is literally shorter now, this thing had to have pulled significant amps for a substantial amount of time.


That is a strange one even for me who has made every mistake imaginable. It doesn’t look like a polarity issue as when I did it my VESC literally went snap crackle and pop and looked cooked as but it might pay to check the battery for a cross connection. Who built it?
It does look more like a short damage wise. I did similar connector damage with my multi meter after my ten year old had been playing with the test leads. Plugging them in different holes etc. best way forward is to use a power supply and try to isolate the issue. Check every connection as I’ve never had a connection spark do that much carnage. Maybe a bit of wayward solder on the VESC xt?

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Don’t think that it was a battery short, but just to be sure…did you check the polarity on your battery. Yes we have seen the red and black wires right on the xt90, but we didn’t see the battery side. If there + and - changed it non the less will short.

Yup I double checked before I charged the battery. If it was wrong I’m guessing I would have found that out then.

Bah. I went to check it again just to get it out of my head. Turns out my red and black leads on my multimeter got switched on me. That’s what I get to lending it out and not paying attention.

That would explain everything. The charger didn’t fry it because I read the + and - with my compromised meter on the charger’s output and matched it with my battery which I also got the + and - ends with my compromised meter.

I feel like a complete idiot.

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No it does not. If I understand correctly you are saying that the polarity on the battery side was reversed. When you connect the battery to the esc with the wrong polarity, you fry the esc not the connector. I have seen my fair share of reverse polarity fried escs since I raced 1/10 electric touring cars and we used bullet connectors to save weight. I will let you guess how many times I have seen this happen :stuck_out_tongue_winking_eye:


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Lol I almost fried a focbox with reverse polarity! I use as150 connectors, and I heard the AS resistor burn up before the esc died, and that saved it!! Super lucky, I’ve since changed my connectors to idiot “resistant” the process

i did exactly what he did (literally exactly the same thing with the meter wires swapped and everything) on my first tb vesc and it still worked fine after. i left it plugged for 2-3 seconds and burned the fuck outta my hands unplugging it

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I fail to see how the electronics on an esc can withstand more current than a properly sized connector when fed with the wrong polarity current. That said I have been wrong before :sunglasses:

Cool xray t3, I runned with xray nt1, these kind of beasts really make you understand basics of mechanics and electronics IMG_5098

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Got new connectors and everything looks to be working fine.

happened to me too, the connecter pushed itself apart in a big cloud of smoke. i assume it burn’t so fast that nothing got damaged on the vesc. :four_leaf_clover: prob. just luck^^