I fried my MakerX Mini FOC Plus

I’m trying to figure out how this happened. One month ago I purchased a Mini FOC Plus because of the form factor (very small), and that it claims to handle up to 80 amps continuously. I’ve put maybe 35-40 miles on it and run it using a 10S8P lithium ion set at 50/-20 amps battery. It is mounted under the board without an enclosure using Velcro so it gets plenty of cooling.

Yesterday, in the middle of a ride it suddenly stopped working. I saw it sparking up a bit. I took the cover off and it’s totally burned up inside. Upon close inspection I noticed that the wire insulation near the large cylindrical component (sorry don’t know its name) had come apart. Could that have possibly caused this?


If you have it exposed than you probably got something conductive in there, either water or metal from the side of the road


Thanks for your reply Zach! I mounted it that way because it came encased as shown in this photo. I am very careful not to ride over water but I can understand how metal particles could work their way in there since it’s not inside an enclosure. You don’t think the rip on the insulation near the connector could be a cause? So I should keep an ESC like this in an enclosure?

A rip would indicate it’s come in contact with material and that could damage the ESC or short parts out. You ALWAYS want your electronics completely shielded, the highest IP rating you can get

Ok, thanks again for your advice.

Looks like your battery lead wires were rubbing on something that shorted them out.


I’m about to put this into a build, what can I do to prevent this from happening? Should I seal all the tiny holes with hot glue and put more heat shrink on the power cable? …any other suggestions?

1 Like

This is what I was thinking too

It was a great ESC before I fried it. Incredibly tiny. Thanks again for the opinions guys!

1 Like

could the short on the cap fry the pcb to such a degree?

The rip looks intentional from the factory to connect the capacitor (the cylindrical thing on the wires) and is on the opposite side from where it would be if it was caused by abrasion.

If the capacitor became disconnected it could definitely cause that.


10S it seems


Could cover it with resin next time. Conformal coating. Take off the lid and paint it.


Epoxy ok to use, or even Spraymax 2K?

I sometimes use epoxy, yes.

The thing about conformal coating is it’s expressly designed for PCBs which means you can solder through it later if you need to repair or rework something. Epoxy is forever.

Epoxy works though. Better, in fact.


Please PM me, I will solve it for you.


PM’d. Thanks for offering to help @YUTW123!


Wow, @YUTW123 really hooked me up! Even though I was very likely at fault. Much appreciated!


Considering two of these in my next street build. Glad to hear that you were able to get such good customer support and it sounds like a replacement unit?

Definitely encouraging to see this from Maker-X

Yes, they were very cool and sent me a replacement free of charge. However, porch pirates stole it when it was delivered. I had such a positive experience that I went ahead and ordered their 75/100 unit.