Cooling off a Raspberry Pi, revisited

Previous: “Cooling off a Pi so it won’t crash

I have to admit that before starting this little experiment I was a little nervous about how it would all work. I wasn’t sure if I’d succeed or if I’d end up frying my Raspberry Pi and possibly a power splitter board, and perhaps a power supply in the process.

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Here’s the setup: I had the Raspberry Pi powered off one of the 5v connectors on a Bitspower X-Station I. There are 3 of them, so in theory this setup should be able to power three Raspberry Pis while also providing for fan cooling on all of them as well. The fan in the picture is a ThermalTake fan that came stock with a ThermalTake Water 2.0 Performer all-in-one CPU water cooler. The fan was plugged into a 12v connector. I later tried a Corsair SP120 High Performance fan as well.

And all of this was powered by a 500W Rosewill Stallion power supply. Note: I needed to use a 4-pin Molex extension cable on the power splitter board as the power supply’s connector had difficulty getting a solid connection that would allow the 12V connectors to be powered.

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The cable connecting the X-Station to the Pi was built from a female-to-female 3-pin fan extension cable distributed with an NZXT Grid, but I had to modify the end going to the Pi. The pinouts for these connectors are, looking down at it from the non-keyed side, pin 1 is ground, pin 2 is 12V, and pin 3 is the RPM sensor signal. To power the Pi on the GPIO, you need to put 5V into Pin 2 and ground into any of the ground pins, the nearest being pin 6. And the keyed connector won’t fit as-is, but you can cut the key slots off the connector and then you can slide it onto the pin array.

So basically you need to change it so Pin 1 on the connector is 12V and pin 3 is the ground with nothing in the middle, as the above picture shows. And to make it fit, just shave or clip off the keyed rails on the connector. If I had the knowledge along with the materials, I might have tried to build something directly rather than adapt something. Perhaps that’s a future project, or I’d solder the wires directly to the board and get rid of the GPIO pins completely.

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And it’s keeping the thing nice and cool, with the copper heatsinks helping as well. That number you see below means the core temperature is registering at 27.171°C (80.9°F). As I mentioned in a previous article, the Pi will crash if the temperature gets into the upper 40s Celsius. And using a Corsair SP120 (a fan typically used on water-cooling radiators for PCs) didn’t fair much better, perhaps a half a degree Celsius at best.

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So now that I’ve got a viable way of powering and cooling the Raspberry Pi, or at least another proof of concept, I’m going to see what else I can do with this. I know that the power board can also be used to power a hard drive, or I can use the power supply for that as well. But as I’m considering an enclosure for all of this, with a fan to keep it all nice and cool, I’ll want it all powered off the Bitspower X-Station, and then I can use a SATA data to USB converter to get it into the Pi.

The reason to go that route is I actually want to set up a small NAS with the Pi as the server. And if I can power everything off the Bitspower board, using a PC power supply, most likely, or something that I can adapt to provide power to it, I should be able to have pretty much an enclosed unit. I’ll see what I can come up with on that. The idea I have in mind for an NAS enclosure is a chimney-type setup with airflow coming from the bottom and exhausting out the top with the Pi, X-Station and hard drive held vertically. And using a hard drive off it would actually give me a sense that I’m doing something with the board as opposed to using a $20 power splitter for just two items.

These temperatures are not significantly better over the 40mm fan I originally used, meaning using an 80mm fan would probably suffice just as well, though a 120mm fan would provide adequate airflow to cool the Pi and a hard drive when blowing across both. Now for just a small media center device, an 80mm or 40mm fan would work just as well.