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I have several 4 wire, 12 volt CPU fans I have collected from salvaged PC's. I want to wire them to run off of an external battery pack. Assuming I am delivering the right voltage, how do I wire these fans to blow at full speed when I turn my switch (The switch being a simple single poll switch in series with circuit)
? any ideas? I cannot seem to find any documentation on which pins/wires do what on a CPU fan
4-pin CPU Fan pinout
I'm not positive on this but if you feed 12V to the fans using the black and yellow wires only you should be able to run them at max. Wiring the fans in parallel will give you max output but will drain the battery faster. Serial will result in less output but longer battery life. The switch in series gives you control over all fans.
Hope that helps.
ok.. call me a critic if you wish... but i would like to know why you want to run CPU fans off of a battery pack? am i right to asume this wont be used in a computer case? if so the wiring is very straight forward... the fans cannot be wires backwards... they will not spin backwards... if u use to little of a voltage... they will go slow.. if u use too much.. u'll burn out your fans... we r a community full of highly knowledgeable modders/technicians who r always willing to help and we welcome you to our forums... have fun
and mod mod mod!!!
PS... r these intel fans? the latest generations have 2 xtra wires... there is a blue green yellow and black
blue and green r relatively useless due to them being used as a tachometer line... yellow is your positive and black is your ground