J4 Environmental Issues

Sixfab Power HAT & Software
#1

I am using the Power hat to operate a Pi 2 in my travel trailer. The Pi 2 is being used because it can operate closer to 60C compared to my Pi3 and Pi4. I am still sorting out ventilation and cooling so hopefully this numbers will come down.

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Note the CPU temperature in the picture. The ambient is approximately 10C lower.
I had to remove the unit from the trailer for maintenance and pressing the clips on J4 caused J4 to disintegrate. The clips did not break off when I first installed it so I assume that the clips broke due to extended (1 week) operation at high temperatures (30-60C) as I live in Arizona and this gets full sun on the outside of the trailer.

I have ordered replacement connectors (SparkFun poke home) but I am likely to solder in a pigtail with a 2.1mm barrel receptacle to simplify connection to my power system.

Comments are welcome along with ideas to reduce the temperature in my trailer while keeping it sealed to the elements while in storage.

#2

I had the same issue with the J4 clips disintegrating… I ended up putting on a pigtail DC Barrel Jack also, using tails that had ferrules on them.

As for the temp, the raspi faq (https://www.raspberrypi.org/documentation/faqs/) states:
" What is its operating temperature? Does it need a heatsink?

The Raspberry Pi is built from commercial chips which are qualified to different temperature ranges; the LAN9514 (LAN9512 on older models with 2 USB ports) is specified by the manufacturers as being qualified from 0°C to 70°C, while the SoC is qualified from -40°C to 85°C. You may well find that the board will work outside those temperatures, but we’re not qualifying the board itself to these extremes.

You should not need to use a heatsink, as the chip used in the Raspberry Pi is equivalent to one used in a mobile phone, and should not become hot enough to require any special cooling. However, depending on the case you are using and the overclocking settings, you might find a heatsink to be advantageous. We do recommend the use of a heatsink if you are overclocking the Raspberry Pi 3 Model B. Of course, if you just like the look of one, you will not hurt the Raspberry Pi by placing an appropriately-sized heatsink on it."

I would not worry too much about the temp, until it starts adversely impacting on the battery charging / discharging for example.

As for how to cool your enclosure, it would help if we had more details: where is it mounted and what environmental conditions other than the temperature do you need to protect it from?

#3

The temperature data was more of a theory and a datapoint on why the connector disintegrated. I have used many electrical connectors on my PCB designs over the years and this is the first time one did that. I would have expected failures after reflow if it was really temperature related but who knows.

I am designing an enclosure for the Pi2 stack that will have some ventilation. The ambient temperature in the back of the trailer reaches 52C in the sun so using enough fans and heatsinks to keep the delta between the ambient and the CPU as low as possible will keep things running. I tried a Pi3 and Pi4 but both of those stopped when the core was near 60C. The Pi2 is easier to keep running at these temperatures.

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#4

Apologies for the delay in response…

I don’t think the connector disintegrating was to do with the temp - I had one do it just on the bench top…

Batteries at higher temps are going to be challenging. Are you powering the setup from a solar panel or are you just battery powering it?

The reason I ask is that if you have a reasonably good source of power (consistent PV, Car 12V etc) then I would just run fans to keep the air flowing. If you have a build up of temp in the trailer that is concerning you, have you considered a whirly bird?

I am keen to hear more about the actual use case for the PI in the trailer…