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Powering computer case fans outside of a computer

Last response: in Components
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May 29, 2012 9:32:25 PM

Hello,

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

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

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!
a b ) Power supply
May 29, 2012 9:49:55 PM

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...

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a b ) Power supply
May 29, 2012 9:55:30 PM

yeah whats in the box?

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a b ) Power supply
May 30, 2012 1:34:42 AM

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.
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May 30, 2012 3:12:59 AM

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?
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Best solution

a b ) Power supply
May 30, 2012 3:51:12 AM

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.
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June 9, 2012 6:47:13 AM

Best answer selected by shoryukenleague.
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