Usb Powered cpu fan

I've got an old stock amd cooler that I want to use to my project but I need to convert it to usb. I've done that but will my laptop be able to power the fan without frying the usb port?
Reply to Naipross
9 answers Last reply
More about usb powered cpu fan
  1. Yes it is entirely possible, as long as you did it correctly you should not fry your laptop.

    But if your implementation is not correct then you can possibly damage the USB phy or hub on your motherboard making said said usb port / hub useless.
    Reply to engineer5261
  2. Ok, I'm pretty sure everything is correct just connected the black wire to the black and red to red
    Reply to Naipross
  3. Naipross said:
    Ok, I'm pretty sure everything is correct just connected the black wire to the black and red to red


    That sounds about right. Make sure to insulate all the wires you are not using. Double check to make sure nothing is shorted, you certainly do not want your Vbus (red) wire touching the GND (black). Use a DMM/multimeter to do a continuity test if you are unsure.

    If everything looks good you should be good to go.
    Reply to engineer5261
  4. There's more to it than just making sure the wires are connected correctly. CPU fans are typically powered by up to 12V, while USB is only 5 V. It's possible the fan may not even start at that voltage. You may also want to check the current rating of the CPU fan, to make sure it doesn't exceed 500 or 900 mA (max current for a USB 2.0 and 3.0 port, respectively). I don't think a CPU fan should draw that much though.
    Reply to TJ Hooker
  5. TJ Hooker said:
    There's more to it than just making sure the wires are connected correctly. CPU fans are typically powered by up to 12V, while USB is only 5 V. It's possible the fan may not even start at that voltage. You may also want to check the current rating of the CPU fan, to make sure it doesn't exceed 500 or 900 mA (max current for a USB 2.0 and 3.0 port, respectively). I don't think a CPU fan should draw that much though.


    That is a good point to consider, however since OP implied using a 2 pin fan I did not consider it. Have not seen a 2 pin fan requiring more than 5V 500mA
    Reply to engineer5261
  6. so everything is fine right?
    Reply to Naipross
  7. Yes, in the sense that it's unlikely the fan would draw more than the USB port could source and damage it. I think there's a definite possibility the fan simply won't start, but you wouldn't damage anything. And in that case you may even be able to get it started by giving the fan a flick with your finger to get it going.
    Reply to TJ Hooker
  8. Yeah everything works I tried it yesterday for like 5 seconds and there was no problem with it spinning just wanted to know that it wouldn't take more power than the sub port could handle and damage it.
    Reply to Naipross
  9. Current limit protection has been there since USB 2.0 specification. You should be okay.
    Reply to engineer5261
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