ESC getting really hot

Hi everyone,

My ESC is getting really hot after only 3km. I know that it affects performance and I don’t want to blow up my ESC. A heat sink doesn’t work well IMO. I though about putting a small fan in my enclosure. Anyone tried that or would it work in the long run? Or, a heat sink is enough?

What ESC and what settings? You might need to turn the amps down.

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Also, what’s the current cooling situation? Is it just sitting inside a sealed enclosure? If heat can’t leave the enclosure fast enough a heat sink could just make it take longer to get to the same final temperature.
Cutting a hole and mounting the ESC over it, exposed to outside air, can be a simpler solution if you don’t want to reduce power.

Did you take the manufacturer’s current ratings as fact?

Which ESC is it? Also post a screenshot of your current settings screen.

A fan is a bad idea; it completely obliterates water resistance efforts.


It is a Tenka wanna be Unity. I am using a backup battery 10s4p which the BMS is 25A max, but I’ve put the motor max to 40A. May this be the issue? Also, my enclosure has my battery and ESC in it and it is a pelican case. I doubt cutting a hole is enough by exposing the ESC but if it works, why not.

Post a screenshot of your current settings screen.

Which settings exactly?

The screen in VESC Tool or Unity Tool with the battery and motor current settings

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What’s your no-load speed in mph?


What do you consider “hot”?

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Hmmm… if it burns the fingers. In vesc tool, I can see the mos temp. In what temp the mos is too much?

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80c is where I call it too hot. I believe the vesc cutoff temp is 90c. What was ur max MOSFET temp?

Changing your gear ratio for a lower no-load speed or increasing your battery voltage and changing the gear ratio for the same no load speed will keep things cooler.

I didn’t saw it. I’ll check next time.

Actually my gear ratio is huge 66/16. May this be the issue?

What size tires?
The fact you’re on pneumatics has something to do with the heat.

7inch pneumatic tires.

i don’t think 7” on 4.1 would create toooo much heat

what kind of terrain are you riding?
hilly or flat