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Hi im struggling with my POE-FAN Hats for my new raspberry pi 4.

Installed several Pi's with the offical POE-HAT: https://www.raspberrypi.org/products/poe-hat/ POE works just fine, but the fans (on every raspberry) wont turn on.

I saw a lot of possible solutions, but only for raspbian OS. My goal is to have an kubernetes cluster so I installed Ubuntu Server 20.04.2 LTS

Currently my Pis have 70°C and more, so they should be warm enough. Checked with pwmconfig and sensors-detect but both say that there are no sensors/fans available.

Does anybody can explain me how to enable the fans? And what are "healthy" temperatures for Pi 4s?

tkan
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  • 70°C?! sounds like a lot. Mines are around 50, close to 1U servers/no AC/in my flat Use ` vcgencmd measure_temp`. See https://raspberrypi.stackexchange.com/a/108/56442 . Ubuntu 20.04 should work, though make sure to use 64b images - better support/more images available – SYN Jul 14 '21 at 00:11
  • Yeah, temperature is really that high. Same on the other 2 Pi's. Already installed the 64bit version, no luck so far. Any other way to initialize those fans? – tkan Jul 14 '21 at 20:11
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    so I just installed Raspbian for once, after the first reboot the fan is working and the Pi has an temperature around 50°C constantly. So everything works with Raspbian – tkan Jul 14 '21 at 20:52
  • Answer from Thijs worked for me! – tkan Aug 03 '21 at 18:37

2 Answers2

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Perhaps this post can help: https://raspberrypi.stackexchange.com/questions/98078/poe-hat-fan-activation-on-os-other-than-raspbian

I might also note that linux kernel 5.13 and newer will have a raspberry poe fan kernel module available but some additional customization of an overlay will be needed and documentation is currently sparse.

Brad Smith
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At the end of file /boot/firmware/usercnf.txt please add dtoverlay=rpi-poe This should activate the default fan settings.

This path is /boot/firmware/config.txt for Ubuntu 21.

Then you can add custom settings like these but I must say that I never get these to work and just use the defaults, it's working for others so worth a try:

dtparam=poe_fan_temp0=50000
dtparam=poe_fan_temp1=58000
dtparam=poe_fan_temp2=64000
dtparam=poe_fan_temp3=68000

When idle my Pi's are around 50C and the room is 25C. These are normal temperatures I think.

Thijs
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  • It worked! **1.** did a fresh install of Ubuntu 20.04.2 and edited the mentioned usercfg.txt. looks like this now: `# Place "config.txt" changes (dtparam, dtoverlay, disable_overscan, etc.) in # this file. Please refer to the README file for a description of the various # configuration files on the boot partition. dtoverlay=rpi-poe dtparam=poe_fan_temp0=50000 dtparam=poe_fan_temp1=58000 dtparam=poe_fan_temp2=64000 dtparam=poe_fan_temp3=68000` **2.** update/upgrade ubuntu **3.** reboot **4.** thank you @Thijs – tkan Aug 03 '21 at 18:34