Topic: Running a component designed for 12v DC from the 14.8v DC an alternator puts out?

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  • 007_SuperCoupe’s Profile Photo
    007_SuperCoupe
    • Join Date: Jul 10, 2006 at 10:09 am
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    #1
    Dec 10, 2007 at 3:29 pm
    I'm curious to know if I can run a component that's designed for 12v DC from a car's electronics. Specifically I want to run a computer cooling fan from the stock electronics. Long story short, there's a module on my car that fails due to heat...and Ford put it on the acc'y bracket! I just want to try to keep it cooler so it will perform better and last longer. I've got a computer heatsink and a cooling fan that I'd like to fix up to help cool it. Is there anything special that I need to do to get it to work? I suspect that I can just wire it up and go with the possibility of some reduced motor life on the fans. I'm not too worried about that as they are designed to last 50k hours. I'm not sure my car will run that much over the next 20 years! Any help would be appreciated.

     

    Sam

    "Someday it will be mine. Oh yes, it will be mine."
    Nebraska ThunderCats

  • likeyoumeanit’s Profile Photo
    likeyoumeanit
    #2
    Dec 10, 2007 at 7:10 pm
    you probably wouldn't have too big of a problem running it that way, but if you want to do it right...
    you should be able to find out either the fan's current draw or resistance, its probably printed on the fan or packaging somewhere. at that point you can use ohms law (v=ir) to calculate the approximate resistance needed to drop the 2.8 V. This wont give you the exact value, but will be an accurate approximation. You can then hook this resistor up in series with the fan...
    You could also use a potentiometer and adjust it until the voltage drop across it reaches 2.8 V.
    Either way just make sure your components can handle the power through them (p=vi)

    if you decide to go this route and have any questions feel free to send me a message.

     

    Drive it like you Stole it, Sin like you Mean it

  • 007_SuperCoupe’s Profile Photo
    007_SuperCoupe
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    #3
    Dec 10, 2007 at 9:56 pm
    My concern is that I don't want to fry the fan motors when I hook them up to power. I got a similar answer to yours on another board. I'm interested in doing it the right way, but am limited not only by space (I'm sure this is very small) but also trying to keep the circuit relatively dry in the engine compartment. Not the easiest thing to do for sure. I'll see if I can look up the technical specs on the fan. There wasn't anything on the packaging at all unfortunately. It's more of a plug and play thing for computers. Basically I was told that I could hook it up, but it would operate at a higher rpm because of the higher volts which will result in decreased motor life, but shouldn't affect the operation other than that. If that's the case, I don't feel too bad about doing it that way. I'll find the tech specs on it and post those here.

    Thanks for your offer of help.

     

    Sam

    "Someday it will be mine. Oh yes, it will be mine."
    Nebraska ThunderCats

  • 007_SuperCoupe’s Profile Photo
    007_SuperCoupe
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    #4
    Dec 10, 2007 at 10:39 pm
    Here's the specs that I found for the fan:

    Quote:
    Specifications
    Rated Voltage: 12V DC
    Max Current: 0.12A
    Power: 1.44 Watt


    They can also be found at this website:
    http://www.gd...tml/hc350.htm

     

    Sam

    "Someday it will be mine. Oh yes, it will be mine."
    Nebraska ThunderCats

  • chickie9797’s Profile Photo
    chickie9797
    • Join Date: Jul 14, 2006 at 12:21 pm
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    #5
    Dec 12, 2007 at 1:09 am
    I have ran a power supply fan on my stereo amp for a while now with no problems. I didn't drop the voltage or anything either. They have some now that are temperature controlled for computers, that way it doesn't have to run all the time.

     


  • ModernMuscle’s Profile Photo
    ModernMuscle
    • Join Date: Jun 12, 2007 at 10:12 pm
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    #6
    Dec 14, 2007 at 11:08 pm
    Basically, as far as power handling is concerned, this would be no different than using a computer fan to cool an amplifier. No problems at all. Most DC power ratings are nominal, so they can work at plus or minus the voltage. Most of the small DC computer fans are actually designed to run at a higher rpm than they will see to ensure reliability. Keeping it dry is another story, but it can be done if you get a bit creative.

     

    Form Follows Function
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  • likeyoumeanit’s Profile Photo
    likeyoumeanit
    #7
    Dec 15, 2007 at 12:34 am
    If this seems to be running fine for other people and you aren't particularly concerned about it then you might as well go with the simple way of doing it, just a recommendation though, make sure you have some way of killing the power to it, we had a similar situation on our box truck at work where there was an after market fan to keep some electronics cool and it overheated and started burning... it filled the whole cab with black smoke and almost caused a wreck on the high way

     

    Drive it like you Stole it, Sin like you Mean it

  • 007_SuperCoupe’s Profile Photo
    007_SuperCoupe
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    #8
    Dec 15, 2007 at 2:26 am
    I'm going to hook it up as is for now. I'll have it hooked up through a switched relay, mainly because I've got one installed already with an open accessory plug. It's controling another fan as well, so it should work out fine. Worst case senario is that the fan motor fries and I'm out $20. Best case it will keep my DIS module cool which will increase its lifespan and increase performance slightly. But more about saving a $150 part than the performance part of it...hehe

     

    Sam

    "Someday it will be mine. Oh yes, it will be mine."
    Nebraska ThunderCats

  • khale’s Profile Photo
    khale
    • Join Date: Sep 24, 2010 at 11:01 pm
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    #9
    Oct 20, 2011 at 9:39 pm
    Quote:
    Originally posted by chickie9797  I have ran a power supply fan on my stereo amp for a while now with no problems. I didn't drop the voltage or anything either. They have some now that are temperature controlled for computers, that way it doesn't have to run all the time.


    Nice idea. I already had a problem in my interior lights and stereo. It somewhat overheated. So i wanted to try this idea of yours. By the way, what actually is the power supply fan did you use in your stereo amp?

     


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