durinnJan 16

How to power a 4-pin CPU fan?

https://programming.dev/post/44144825

Show threadfuzzy_tinkerJan 16

1st, do not power the fan from the pi if possible to avoid any underpower headaches. It should be fine.

Your best bet is to just power it at 5v using a standard USB wall wart and a sacrificial USB cable (old 2.0 ones work best). Strip the USB cable and expose the positive and negative wires and hook them up to the positive and negative fan pins (identify these using a 4pin fan header diagram). You can either try just shoving the tips of the USB cable into the fan header using electrical tape as a quick bodge, or cut and strip the fan cables and twist them together.

Show threaddurinn
Gotcha! Thanks for the directions! Any reason why I shouldn’t power it with 12V, since it says 12 on the fan…?
Jan 16 at 10:09pmWeb
Show threadstevestevesteveJan 16
You should indeed power it with 12v
Show threadRomkslrquszJan 17
Assuming the supply can saturate the current the fan will use, at 12V it’ll be running at full speed. That’s probably pretty loud. Give it 5V, it’ll run just under half speed.
Show threaddurinnJan 17
I just found a “noise reduction cable” from Noctua. It ads 51 Ohms. I have no idea how to calculate what the new voltage would be on a 12V 2A DC power supply ( www.noctua.at/en/products/nv-ps1/specifications ), but Noctua’s website says that the cable lowers fan speeds, so I’ll give it a try.
Show threadRomkslrquszJan 17

Yeah, it’s just an inline resistor

A potentiometer is a resistor that you adjust using a dial. If you want control, you may want to get a PWM fan control module. There’s the Noctua NA-FC1 www.noctua.at/en/products/na-fc1 but that’s pretty much just a fancy expensive version, you can find the same concept for as little as $1-2 USD