Smokey The VESC -- Unsure cause

I’m working on my first build: Battery: 10S4P Lith-Ion BMS: BesTech HCX-D223V1 Dual VESC: Torque ESC x2 Dual Motors: KEDA 6364 x2

I wanted to set up my ESC which seems to require the battery to be plugged in to do so because nothing lights up when using the micro usb.

When I plugged my battery into a singular ESC, w/o the BMS or Motor, the positive terminal melted and started smoking. The rest of the ESC looks fine and w/o any burn marks, just the positive terminal on both my battery and ESC need to be replaced.

Can anyone let me know what caused this? I don’t really want to repeat it.

ESC: esc

ESC Terminal: esc%20terminal

Battery Terminal: battery%20terminal

upclose pictures of the (vesc)board itsself?

Perhapse the xt90 was soldered to the wrong wires? like + to - and - to +. I’ve done that before and it sparked a lot and blew my VESC… :sweat_smile:

1 Like

my first thought was reversed polarity but the connectors look good. yeah, like @anon64938381 said get some pics of the PCB


one immediate thought for possibilities was that 1) the male connector prong was maybe pinched and/or had some kind of shipping oil or ooze on it or 2) there was something like that in the female socket and all of that lit up when it both made a bad connection and was interfered with by mystery material

that positive prong and socket both look slagged up now though, so hard to say

Pictures of the board itself. I don’t really want to remove the heat shrink, sorry. 859065132884541390 8375025877482848890

polarity looks good on the board. Check to see if anything is shorting the big caps in any way, maybe a hair of a wire or something

1 Like

Everything looks good at the Caps. If there was a hair of wire, that should have burned up before the terminal or at least caused some smoke, but everything came from the terminal.


i dont see anything wrong either… but ive never seen that blonde part of the board looks different from what ive seen, im going to look at the saved pictures of my old torque vescs i have so i can compare… maybe your board is literally missing something?

Do battery connections need to be made instantaneously via a switch? I haven’t had a problem like this before with my past RC projects, but nothing has had this kind voltage or current numbers.

no you can just plug and unplug a vesc normally from the battery pack, it will spark (hense antispark,) but nothing bad with happen. Maybe something is wrong with the battery?

1 Like

Just looking at the board the only thing I might be missing is a resistor that is most likely for the micro usb.


I don’t know if it is intentional, but I doubt it would cause my problem.

1 Like

you know what… i thikn you’re just experiencing connection pop because you don’t have an antispark and you’re just jamming a couple of XT60s together.

even without something in the socket or bent prongs to exacerbate it, its still going to pop and spark and light up and probably blacken the connector.


I think you might be right. I’ll get an antispark I haven’t even looked into that. And now I’m out of XT90 connectors as well. So I’ll be playing the ol’ waiting game again.

1 Like

ah duh i overlooked that :thinking:

but wouldnt(shouldnt***) the pack come with a xt90? unless you made it yourself @Lanik

It probably would, looking into an antispark now. I will need to replace those connectors that melted though. And I’m all out now.

i’ve got some connectors lying around but they are xt90.


This is one of the reasons I do not like XT connectors. I have been using EC5 connectors on my 12S helis and never experienced something like that since both the male and female sides of the connectors are isolated.


1 Like

XT90 ≠ XT90AS

Try an XT90AS or XT90 antispark as used in loopkeys. Or, just use a loopkey made from an XT90AS. Or use an antispark switch.

It’s possible the melting happened because the empty capacitors on the VESC board were an effective short circuit for a very brief moment while they are charging-up. You have to connect it gently (from an electrical perspective, not a physical perspective)

1 Like

The arcing that happens on connection… the spark… isn’t because of a lack of isolation. Its not caused by shorting. It happens as a result of the gap closing as the connector properly makes its connection. The potential is such that it arcs prior to making total contact.