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12v computer PC fans powered by 5V USB Answered

Hi folks, I have a mains powered USB hub and have successfully powered some 12V, 0.08A PC fans with a USB cable. I was wondering if powering 12V fans with 5V power supply would somehow damage the USB hub over time?

I was also going to power some other things from the hub and thought of getting a luster/screw terminal to group power the fans from one USB cable (saving me some USB port space to power the other things). Could you foresee any problems with this?

Thanks in advance :)


The main problem I see is the lack of power for the fans.

If you have a 5V supply you 5V fans, if you have 12V...

A PC fan does not use much power and if you use a mains powered hub anyway why not use a 12V adapter instead?

Get a 12V/1.5A one and you can run at least 10 fans on it with no problem.

And no, as long the combined power consumption of all connected to the hub is below it's rating nothing will happen.

Thanks, you are totally right. I thought it would be too difficult to connect those 12v wall power supplies to stuff, but after a little googling, I realised it's just as easy as usb once you know which is the + and - wires.

usually, even if you get polarity (+,-) reversed, it just means your dc motor runs backwards.

PC fans are usually powered by a PWM controlled motor, reversing the polarity will either do nothing at all or cause the electronics to go up in smoke.