Why DC 12 Volt fan so noisy??

Discussion in 'Designing, building, making and powering your life' started by Shack Living, Jan 15, 2007.

  1. Shack Living

    Shack Living Junior Member

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    I bought a 12volt fan from super cheap (designed to plug into cigatette lighter for a car) to keep me cool while sleeping in hot nights in a caravan. It sounded like a aeroplane taking off!! I thought it might have been the blade, but its the motor. Is there a way of having a quiet 12volt powered fan? 240 volt ac fans seem whisper quiet in comparison?
     
  2. christopher

    christopher Junior Member

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    The operative word here is "cheap". There are excellent German 12vdc fans. They move lots of air, and cost lots of money....

    In life, mostly, ya get what ya pay for! You bought a cheap fan!

    BTW, I have a cheap 12vdc fan by my desk. It sounds like an aeroplane, too. I used to have one by my bed, and the noise lulled me to sleep.....
     
  3. Shack Living

    Shack Living Junior Member

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    Any recommendations of a particular make/model? Is it the motors that cost the $$'s? or the person putting them in the fans? Perhaps if I could get hold of on of these good german motors, I could fit it into a 240V fan?
     
  4. Richard on Maui

    Richard on Maui Junior Member

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    I have a cheap 12v fan. I pulled it out of the dead vw truck that is sitting in the yard! :lol:
    I guess it makes a fair bit of noise. I am going to use it in a food dehydrator one of these days.
     
  5. christopher

    christopher Junior Member

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    There are lots of 12vdc gfans for cooling computers, and they are pretty cheap, buit they are not really for cooling bodies. Having one at your desk pointed at your forehead might keep you a lee bit cooler...

    I found these on amazon:
    https://www.amazon.com/Caframo-Ultimate- ... B0000AY31M

    They both get good reviews....
     
  6. Shack Living

    Shack Living Junior Member

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    Thanks heaps for the link. Unfortunately I cant purchase these fans from amazon, as I get the message "We're sorry. This item can't be shipped to your selected destination.". I havnt seen any high quality 12V DC fans in Australia, and with temps around 40'C atm, its easy to justify buying something like this.
     
  7. strud

    strud Junior Member

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    why not run a 240Vac fan off an inverter ?

    What sort of power rating is the fan ?

    300W inverters are only about $45 or so these days !
     
  8. christopher

    christopher Junior Member

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    One reason is DC fans are a lot more efficient at moving air than AC fans.

    Another reeason is that inverters are at most %88 efficient in converting DC to AC, so using something DC direct would avoid the loss..
     
  9. Shack Living

    Shack Living Junior Member

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    Yeah, power consumption is important to keep as low as possible. After surfing the net for a while, I came across this article:
    https://www.setsail.com/s_logs/bannerot/bannerot31.html
    basically, they recommend a 12 volt Hella Jet fan. On an American website they retail for about US$25. But when I asked for a price in Australia, I was told AUS$104.06 for the same model :-x :(
     
  10. Shack Living

    Shack Living Junior Member

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  11. the brutus

    the brutus Junior Member

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    Re: Why DC 12 Volt fan so noisy??

    If you are looking for a 12V fan that is efficient and cheap, I would recommend one of the larger units designed for computer ventilation. I don't mean the little 2" CPU coolers, there exist big brutes of 8" and above. They are quiet and extremely efficient, and also very long lived. They are not exactly a pretty unit, but some creativity on your part can glam 'em up as much as your aesthetic sense demands!

    I would suggest an electronics supply store, we have an Active Electronics down here in Tas that seems pretty good for that kind of thing. They are not as cheap as the dodgy Chinese units you describe, but if you are off-grid the gain in efficiency has real economic value if it allows you to keep your system small. At $10 per peak watt for solar/battery, that extra 20W gained through efficiency might pay for more than the difference in fan prices, but you'll know your system better than I can.

    All the best

    Brett
     
  12. JoeD

    JoeD New Member

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    Re: Why DC 12 Volt fan so noisy??

    For 12 Volt stuff I always check 12 Volt Travel's website. I've dealt with them in the past and it was a good experience. Once I do business with an online store, if all goes well, I always check their site.

    As far as your fan I see they have a two speed 12 Volt fan, the two speed thing is what got my attention. It's bound to be quiet on low speed and you still have high speed when you need it.

    I couldn't help but notice that they don't go out of their way to say it's quiet, but I've seen it compared to the EndlessBreeze unit. Twenty bucks.
     
  13. GoddamnBats

    GoddamnBats Junior Member

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    Re: Why DC 12 Volt fan so noisy??

    I have one of the fans from the site JoeD listed, for my room. It does the job, not too noisy at all and it was $20 from Kmart in Perth
    Just had to get a 12 volt cigarette lighter plug (the same type that fits my set-top box) and it runs straight from my 12 volt house wiring.
    Great success!
     

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