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My fans are on molex but are not running at full 12v?

Last response: in Components
May 18, 2012 4:24:32 AM

shouldn't they be running at a full 12v there's 2 200mm,1 140mm and 1 230mm with red leds
a c 76 ) Power supply
May 18, 2012 4:56:17 AM

If they're 12V, they should be at 12V regardless of what they're plugged into. PWM is still 12V, just modulated to allow speed control.

I'm guessing you mean they're not at full speed, which I have no answer for. There's no reason they shouldn't be when plugged into molex.
May 18, 2012 5:12:40 AM

could it be from running them all off the same line of connectors? maybe ill have to take the multi meter to them and see whats going on
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a c 76 ) Power supply
May 18, 2012 5:16:56 AM

It could be that, I guess, but it shouldn't be really. Most fans pull something like 0.2A each, so it shouldn't really be a huge drain. Try the muti meter to see if there IS a problem though.
May 18, 2012 5:25:39 AM

that's odd, 12.22v so no problem there maybe i just expected the fans to run faster and push more air then they do

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May 18, 2012 5:49:40 PM

if the rail is at 12.2 volts then they are getting the correct voltage and wattage should not be an issue b/c fans only pull between 2-7watts. Big fans push alot of air just over a large area so it could be they are running at the right RPM and pushing the correct amount of CFM but just over a large area. it will not feel like it is moving as much as say an 80mil moving the same amount of air... (AKA theoretical focus flow.) (that would probably be one Crazy loud 80mil. lol!) Keep in mind the larger the fan, generally the slower the RPM for the same airflow which also reduces noise. that is the major benifit of larger fans is reduced noise the area the flow focuses on.

here is a 80 mil 40cfm that runs at 2800

compared to a 140 mil 43cfm that runs at 800 RPM

the 140 mil fan will not look or feel like it is not moving as much air as the 80 mil but it is just over a larger area.

anyway if you feel they are not performing as intended i would contact the manufacturer and see what they say about it.
May 18, 2012 5:54:08 PM

Best answer selected by robthatguyx.