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Will it hurt the pi if I run a fan on the 3.3v gpio? I have a hdmi lcd screen on mine and I don't want to use the usb ports for a fan. I have a raspberry pi 3 by the way

  • Also I am a noob – kyran bullard Mar 9 '17 at 22:37
  • Why not use 5v instead of 3v3? You will get more power. – anonymoose Mar 9 '17 at 23:40
  • The 5v are already taken by a lcd screen and I don't need much air flow and I know it won't make the fan run 100%, I just need to know if it could damage the pi? – kyran bullard Mar 10 '17 at 0:14
  • Do you mean the 5v pin is physically blocked? – anonymoose Mar 10 '17 at 1:28
  • Yes it is, it powers my lcd – kyran bullard Mar 10 '17 at 2:08
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The short answer is yes.

The long answer is yes, but...

3.3VDC is enough to run a low speed fan provided its designed for 3.3VDC.

I wouldn't try anything larger than a 40mm fan like this one, and this is why: the larger the fan blades are, the more torque is required to turn them, in in turn requires more power.

When you only have 3.3 volts, it takes 4 times the amount of current than with 12 volts most computer case fans run on. Also, the fan speed will not be as fast as the regular computer case fans either.

But yes, it can work for you.

A quick google search found a few pre-made options like this one on Amazon for one with a fan running on the Pi GPIO pins. .

I can neither speak for nor against either of these fans as I have not used them, they were just the first reasonable hits in my google search for "3.3v case fans".

  • The 5v are already taken by a lcd screen and I don't need much air flow and I know it won't make the fan run 100%, I just need to know if it could damage the pi – kyran bullard Mar 10 '17 at 0:15
  • @kyranbullard No, it won't hurt the RPi to connect a 12v fan. A fan is just a DC motor, it will spin or it won't. But it won't draw so much juice that it will fry something. – Sandor Dosa Mar 10 '17 at 0:24
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You can draw up to 800 mA from the Pi 3.3V. See Raspberry Pi Power Limitations

Why you would want to run a fan (3.3V or other) on the Pi is a mystery.

  • The RPI3 can require a fan in certain circumstances to avoid throttling. That being said I wouldn't want a 3.3v fan, but if nothing else that should suffice. – Brett Reinhard Mar 10 '17 at 14:10
  • After making the portable gaming system I played it for quite some time, and when I went to the command screen there was a little icon of a thermometer flashing on the right side of the screen and I could feel it getting warm, so I put a small fan by it and it stops. I don't want to have to carry around a usb fan for it, so I'm putting a small fan in the case – kyran bullard Mar 10 '17 at 17:10

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