Powering computer case fans outside of a computer


I'm trying to build a box with fans in it. I've got these fans:

How do I power these fans? I don't want to use 250w just to power four fans with a cheap computer power supply.

Any suggestions? Thank you!
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  1. if you did use the psu you would only use the prower the fans need which is less than 10w each + what ever the efficiency rating of the psu is. so you would likely be using about 25w total to power the 4 of em...
    what you gonna use the box for coz they aint particularly good fans...
  2. yeah whats in the box?
  3. These fans require 12VDC supply. I can't find a spec for their current draw, but typically one of these might use at max 1 amp for starting current, and less while running. So for four connected in parallel to one 12VDC supply, the supply should be able to provide 4 amps or so max. Wiring code of the fan wires is: Black to Negative, Red to Positive of the supply. Do not connect anything to the fans' yellow wires - they are pulse output signals for speed measurment you are not going to be doing.
  4. Thanks for the information!

    Just to clarify, you're saying the best way is to just run them through a cheap computer power supply, right?
  5. Best answer
    That might be just as cheap (or better) as trying to find a power supply for 12 VDC, 5 amps. NOTE that most PSU's do NOT have power output connectors for a 3-pin fan, which is what you have. BUT you can buy adapters to convert a 4-pin Molex output into one or two 3-pin fan outputs.

    Check on one other detail. Many computer PSU's will not turn on unless there is a modest load on one of the output lines, and I don't remember the details. Look for hints in areas that talk about how to test PSU's. They should talk about where to connect a resistor or small load so that it will turn on when two particular output wires are shorted together momentarily. Then also check how you turn it off.
  6. Best answer selected by shoryukenleague.
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