What's a Good Temperature?

[davidbu99]

I had the day off so have been "refurbishing" my PAW. I've upgraded to a Model 3B+ and continue to use my Rosetta low power SDR and also a Stratux GPYes ublox 8. In addition of course loaded the latest and greatest software. I was hoping the temperatures would be more reasonable than before but they seem the same.

I placed the unit on a windowsill in the sun with an ambient temperature of 24 celsius and after a couple of hours the unit peaked at around 71 celsius. I had an ipad and SKD connected throughout. There was no throttling reported. In the cockpit of our PA28 on a hotter day I could see this going higher.

Is there any guidance or experience on what a more normal temperature would look like and in particular at what temperature will the processor start throttling? I am also assuming its the close proximity of the Bridge that affects this as well?

Lastly, any experience on fitting heatsinks and/or fans? The 3B+ has a much better metal screen on the SoC and I doubt there is space to fit anything due to the Bridge piggyback. I saw some prior comments on the use of fans affecting the Bridge due to changing the air pressure in the case but these seem to have been not proven. I've a couple of 30mm case fans and was considering wiring these into the 3B+.

Welcome any feedback and experience.

Well done to the PAW team by the way for the new release (I've already done a flight test and was impressed!).

[Admin]

85’C and below
Above this the clock speeds are throttled back

In testing we increased reported temp to 104’C, using a heat source
It carried on working regardless

The bridge generates very little heat, its all the pi and sdr
Thx
Lee

[Paul_Sengupta]

On all my PIs from the 2 onwards, I've used something like this:

https://www.aliexpress.com/item/32860853389.html

There's a thought that the 3B+ uses more power and gets hotter, and that the 3B is better in this regard. Indeed, I read a post on the Stratux board saying as such, and the Stratux people invariable use fans in their cases.

The low power SDR won't keep the PI much cooler but should stay cooler in itself.

[exfirepro]

Hi David,

As Lee has said, most of the heat is generated in the Pi and the SDRs, so when we were doing testing with 2 x SDRs (to investigate UAT weather reception), I fitted a small fan in the end case of my Rosetta - below where the SDRs sit - for a test flight down to Popham ‘just in case’. I ran fan all the way down from East Fortune on the Thursday then back via the south coast and Damyn’s Hall on the Monday / Tuesday. The Wx was hot enough on the Monday to shut down my iPad mini - which was out in the sun, but the Rosetta ran faultlessly.

After returning to home base, however I monitored the unit temp for a while, both with and without the fan and realised that it wasn’t really needed, so disconnected it to reduce power drain. It’s currently still in the case, just not connected.

So perfectly feasible, but worth monitoring the CPU core temp first to see whether it’s really necessary as per the thresholds in Lee’s post.

Regards

Peter

[davidbu99]

Peter, Paul, Lee, thanks for the feedback. I'll do some further flight tests over the next 2 weeks and report back my findings.