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  • Author Author: clickio
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UPDATE: under 40 degrees C!!! Lowest idle cpu temp so far on the BeagleBone AI SBC! how-to and pictures inside

clickio

OK, it shouldn't be a surprise to anyone that this board gets H-O-T. It's not something to be held in the palm of your hand, so it's not that critical. Until it is. Because, as all/most CPUs, it halts when reaching a certain temperature in order to prevent a complete meltdown. In its case, its probably around 85-100 degrees Celsius.(I'll update the exact figure if I find it in the documentation)

 

So one of the key things for maximizing the use of this SBC is cooling it properly. There is currently a fan cooler solution (this one was kindly provided to me by element14 for the dedicated RoadTest), a dedicated cooling cape (a plug-in board just like HATs for Raspberry PI) and I think that we will see even more solutions in the future, possibly a dual-fan solution to heat both sides of the board, as in my testing a very primitive simulation of this reached the lowest cpu temp.

 

I say 'primitive' because the only thing I did was placing the board on a laptop cooler with large cooling fans, as shown in the picture.

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And here is the result!

 

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As a recap, my test results for idle cpu temps were:

 

1. 61,8 - 64,2 degrees Celsius with just the supplied heatsink, passive cooling

2. 50,6 - 53,4 degrees Celsius  with the 5V F251R-05LLC brushless fan cooler attached

3.  48,6 - 50,6 degrees Celsius  with both the 5V F251R-05LLC brushless fan cooler attached and the board placed on the laptop cooler.

 

So cooling from both sides improves the cpu temperature with 2-5 degrees Celsius, by just using this simulation, I bet that by using a second heatsink + dedicated fan can make a lot more difference.

 

LATER EDIT: It even got as low as 47,8 with my dual-active cooling setup!!!

image

 

IMPORTANT UPDATES: going under 40 degrees!!!

 

Enclosure update: Thanks to who had a few spares (see his article here: BeagleBone AI (BB-AI) - Getting Started )and was very kind to send them over, my BBAI now is housed in a white-plastic enclosure, which I'll try to use as a base for a dual-active cooling solution. Yes, I still haven't found shorter screws yet!:)

 

imageimageimage

 

Cooling update:

 

I've finally achieved maximum cooling with this board, let me tell you how I did it. Now I really feel  I can try the machine-learning features without any worry of overheating and/or unexpected halts because of that.

 

Based on 's enclosure, I added another tall floor under the board, where I fitted a 12V cooler powered independently from the board. I also added passive cooling to all the black chips on the top side (RAM memory, eMMC memory and the TPS659037 power management chip) and to the one on the underside (second RAM memory chip) with the help of some microporous heatsinks and now the board stays below 40 degrees in regular usage.

 

Here are the pix!

image image

And the test results:

 

WITH underside cooling:

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WITHOUT underside cooling (I took the cooler off the 'contraption'):

 

image

  • in reply to colporteur

    Hi Sean,

     

    I think (but only at a 75% confidence level) that it likely doesn't need very extreme cooling, from the little test I tried, (my BB-AI has a 40mm fan, and I extended the heatsink size, but not beyond the footprint of the BB-AI, and shallower than the header pins) once the BB-AI is idling. the current draw is less than 750mA (this is including a small fan), so under 4W of power, i.e. enough to need at least a heatsink if not a small fan too. I operated the BB-AI in about 23 deg C ambient with the small fan, with an old image.

    I tried 'stress --cpu 4 --timeout 60' (not a great command, but I didn't spend much time exploring how better to test it), it only slightly increased to maybe 4.2W. The BB-AI has lots of extra features on the chip (all the accelerators and extra processors that Linux doesn't use by default) so the power could increase a lot more maybe but I've not seen any figures (it is likely investigated by others already to some extent, since the BB-AI is based on an older X-15 board which has been around for a couple of years).

     

    It is annoying though, having to listen to a small fan! : ) A slightly bigger fan (maybe 50mm?) may be better on the audio side..

  • in reply to colporteur

    I think BBAI is a cool pioneering device and it has a huge potential if they solve its initial issues. Keep an eye on the wiki for details:

    https://github.com/beagleboard/beaglebone-ai/wiki/System-Reference-Manual#board-changes

     

    Yes, right now active cooling it's definitely required on the BBAI, but i'd say at this point it's a known issue and I hope they take steps to solve it. Even Raspberry Pi's got a few degrees cooler with a software update.

    They do recommend a fan though it's not included in the package: https://github.com/beagleboard/beaglebone-ai/wiki/Frequently-Asked-Questions#fans

  • A philosophical question I thought of after reading your review, when is CPU cooling required verses recommended?

     

    Heat sinks and cooling fans are additional components and additional cost to manufacture. If they are required then pins to support power connections and power requirements need to be part of the solution. I don't like the implications of the buyer being left to decide.

     

    Your comment that the unit got HOT just performing an update to me suggests it requires a cooler and is not optional.

  • Good work, it is too bad that the board was not built with adequate thermal dissipation in mind.

     

    DAB

  • in reply to clem57

    It definitely has, they just need to fix a few issues, heating being one and the installed libraries, the second.