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Can Jevois be passive cooled?

0 votes
Well of course it can! :)

Question is if someone has already done it?

Other question: is the chip the chip protecting itself from overheating? If I put some heat spreaders on it and it is not enough cooling I wouldn't like to fry it!

asked Dec 30, 2018 in Hardware Questions by poesel (130 points)

1 Answer

+1 vote
yes, we have done it, in fact we originally hoped we could get away with a heatsink but it would have to be so big that we finally opted for a fan.

If you are not in a hurry, you can affix a heatsink (we used 30mm x 20mm x 6mm) using heat-conductive epoxy glue.

You will quickly overheat under high load (e.g., tensorflow). But you could reduce the CPU frequency using parameter cpumax documented here: http://jevois.org/doc/UserCli.html

for example,

setpar cpumax 600

will cap you to 600Mhz, You should be able to run heavy loads without overheating at that speed. In fact the RPi slows down to 600MHz when it overheats and has no fan.
answered Jan 4, 2019 by JeVois (46,580 points)
If 30x20x6 isn't enough how big does it need to be? Space is of no concern in my application.

If the cooling isn't enough will the automatically slow down?

You can find some calculators online by searching for "heat sink calculators", for example https://celsiainc.com/heat-sink-size-calculator/

Assume that the CPU power is 4 Watts (this depends on what algorithm you are running). Then you need data from the kind of heatsink you will use and the kind of glue you will use. Then you can get an estimate of the required size. If you want only natural convection (Rv=800) it could get quite large, like 60 x 60 x 30mm.

Just be careful if your heatsink is wide to protect the solder joints of the header pins that are to the sides of the processor.
we have now posted a heatsink conversion tutorial here: http://jevois.org/doc/Fanless.html

as it turns out, 30x30x20mm with spike-style fins seems to be working great.
Cool - thanks a lot!