VESC fan cooling with auto ON/OFF

Bit bored so have ordered some parts to do some fan cooling for the Focbox unity with temp based auto on/off so not to have it on all the time and drain the battery.

Basically, the idea is to use a step-down 12v converter straight from the battery and use a thermal switch that can turn itself on and off depending on the temperate of the heatsink on the unity.

here is what I have. Two fans 50mmx50mm each. Just going to use thermal glue or double sided thermal tape to attach to the bottom of the unity heatsink.

The step down converter

This is the switch I am going to use

Just not sure which one to get with regards to temp on/off. Here is the chart. I like the one which turns on at 50c and turns off at 35c but open to ideas.

Here is the bottom of the unity

The fans should leave enough space at the top to screw the temp sensor in one of the top two holes.

I don’t even need this. I am 65 kilos and cruise at 18mph. LOL but its either this or another grand on a new board. I am feeling the itch to do something.




did you ever end up doing this?


No. Got busy unfortunately.

Well I’m about to take it on actually

Nice. What temp sensors did you go for?

Hoping i can make everything work together nicely.

Why don’t you grab the smaller switches like these?

Fans use like 0.1 amps

I ordered these last night too. I was just curious about the programmable ones.

I’m not exactly sure how they are supposed to be wired in yet

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the 48 to 12v converter is huge. would like to find something smaller

Its 10a. You need something like 1-2a. Fans don’t need much amps at all

yeah I know it’s 10A. its the only one I saw on amazon at first.The programmable temp sensor was able to take 10A on input side and put out .8 and below amps on fan side

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Hey, I have some smaller bucks converters coming in today from Alibaba. Lmk if you have any interest, they are fully waterproof and I have a few extras of each kind. They said for longevity it’s a good idea to run them 80% of their rating so 2.4Amps for the 3A and 4Amps for the 5A. Have used them in my builds before and they work great for headlights or horns.

30-72V to 12V 3A output is 46x32x18mm


30-72V to 12V 5A output is 58x40x22mm.

Here’s a picture of what they look like. Since it’s 30-72V They should work great from 10s-15s

I’m certainly interested

Yeah im interested