PC fan in a circuit is really slow...

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MitchP

MitchP

New Member
Oct 6, 2012
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Santa Rosa, CA
I installed two 5v pc fans into my paintball mask today. I am using a 9v battery, and it is controlled by an ON/OFF button switch. Anyways when I turned the fans on after it was assembled, they started slowing down like the battery was dying. After maybe 10-15 seconds they don't have enough power to remove humidity. I have checked for a short circuit but I couldn't find any. I feel that I may have used too much wire (about 13 inches of wire total) and it's losing power. Are the fans drawing too much power?
 
2door

2door

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Sep 15, 2008
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Littleton, Colorado
Your fan amperage is too much for the batteries. Voltage might be sufficient but the current draw is overcoming the amp hour rating of the battery. You'll have to go bigger on your battery but be careful. If you fans are 5 VDC you don't want to apply much more than 6 VDC.

Tom
 
MEASURE TWICE

MEASURE TWICE

Well-Known Member
Jul 13, 2010
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Or use a lithium polymer battery. I actually have a single sell LIPO that I use a DC to DC converter to step up the voltage or down. The DC to DC converter goes output 1.5 to 15 dvc or something at about 1 amp.

I was trying to reduce weight of a 9 volt transistor battery I used to use to power a color wireless video camera on a small RC helicopter. Now I find the RC toy is just hard on the battery that runs it and so I have this camera that is really small and light weight with its own power system left over. I expect it should be mounted on my helmet when I go out the trails. Some where on board I could set up the wireless receiver to record on some kind of media my travels.

Note: LIPO Cells are need to have a short circuit protector chip if they do not already come with one, as shorting those can be more than just a little dangerous!

MT
 
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scotto-

scotto-

Custom 4-Stroke Bike Builder
Jun 3, 2010
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Ridin' inSane Diego, CA.
You current battery is way too small (A/hr wise)....even if doubled up. If you're running your fans in series, that's 10v. If you're running them parallel, your just wasting your time.
 
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Pilotgeek

Pilotgeek

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Apr 6, 2011
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Green Bay, WI
I agree with the current being too low. Try an RC car battery pack, or go to radioshack and pick up a battery holder for 4AA cells. Also, make sure you aren't doing anything weird with the rpm wire on a comptuer fan, just hook up positive and negative.
 
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