Heat spreader base plate and its function and importance in the grand scheme.

Ken

So I am just curious about what component is being cooled by the base plate on the Ups, and how important it is. The reason I ask is that that plate pretty much makes the board not a form factor replacement for a Pi. I am using DIN mount enclosures for my projects which started out as a Pi project, and the spreader plates make these pretty much unusable. I mean to be quite honest the component stack I was using barely fit to begin with so I am not sure in the big picture it is truly important, but I felt it was a worthy general question as I can't be the only one who is looking to recycle Pi parts.

Ken

If removing the heat spreader plate is not advisable, my plan B is to use one of these:

Electronic Housing-Universal DIN Rail Adapter, UTA 89 Series

And simply rivet it onto the base plate to get my DIN mount. This then brings up another question: What is the interface material between the heat spreader and whatever chip is being cooled? ...and can that plate be removed and reinstalled in a non destructive way?

Dan O'Donovan

This isn't an official answer, just my own opinion:

The base plate can be removed, but please be aware that this will obviously reduce the heat dissipation from the board. Unlike the heat-sink on top, it is not in *direct* contact with any of the hot ICs as far as I know, but is nonetheless effective at pulling a significant amount of heat away from the CPU.

In my view, most of the heat generated by the SoC typically comes from intensive use of the GPU and, to a lesser extent, the CPU. If your application isn't using these intensively, and/or you don't mind the CPU throttling (reducing its clock frequency) if it starts getting too hot, then it will probably be ok for you. I suggest that you run some tests, keep an eye on the CPU temperatures and see if it meets your needs with the base plate removed.

The dynamic throttling and frequency scaling is a nice feature of these Intel CPUs, in my opinion. Rather than letting themselves overheat beyond the point of critical shutdown or worse (melting!), they'll try their best to maintain a working temperature (<= 80 degrees C) by reducing CPU frequency and marching on. You can observe this behaviour using a utility such as 'i7z' which reports CPU frequency and core temperatures.

Ken

Thanks again Dan, what about my second question, do you have any info on what the thermal media is on the plate and whether it can be removed without destroying it, so that it can be reinstalled afterward?

Dan O'Donovan

I'm not sure of the exact material used for that thermal pad. But I was able to remove it easily without destroying it on my board. Its not very sticky, as its held in place by the plate, so it can be peeled off easily, and probably re-used if needed (perhaps slightly less effective if re-used; I'm not sure). Or I imagine it could be replaced with another pad of similar thickness.

Ken

OK, good information, when I bought mine, I also bought the active heat sinks, the heat transfer pads on the original passive sinks was not something that could be reliably removed and reinstalled. Anyway I look at it, I will need to remove the plate to make a mounting.