Powering a 12v dc computer fan with batteries

Discussion in 'The Projects Forum' started by r_dawson12, Jul 27, 2013.

  1. r_dawson12

    Thread Starter New Member

    Jul 27, 2013
    7
    0
    Hey guys, I'm thinking of doing a very basic project. I'd like to make a portable air conditioner using a 12v fan powered by 8 AA batteries. You may have seen them, it's essentially a computer fan that pulls air from the outside, into a container filled with ice, and then there is a vent of sorts that the cooler air is pushed out of. My questions is would something like this:

    http://www.amazon.com/electronics/dp/B00CQKCXXE

    Work for powering a fan along these lines:

    Fan


    Thanks in advance, and sorry if this is a stupid question...I'm pretty new to electronics :p
     
    Last edited: Jul 27, 2013
  2. wayneh

    Expert

    Sep 9, 2010
    12,120
    3,046
    Yup, that'd work fine.

    You might consider pre-cooling the incoming air with a swamp cooler, basically cooling it by evaporating water into it. It adds humidity, but since you're passing the air over ice anyway...

    Perhaps just have it all oriented vertically so that incoming air passes over the water that has thawed off the ice.
     
  3. r_dawson12

    Thread Starter New Member

    Jul 27, 2013
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    I'll be using out outside and I'd like to keep it rather compact and portable. My GF will use it at my softball games I'm sure and she just had shoulder surgery so she wont be able to carry much lol.
     
  4. r_dawson12

    Thread Starter New Member

    Jul 27, 2013
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    Also, this might seem like a stupid question, but do I attach red to red or red to black?
     
  5. Metalmann

    Active Member

    Dec 8, 2012
    700
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    yep, red to red.
     
  6. r_dawson12

    Thread Starter New Member

    Jul 27, 2013
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    Awesome, thank you!
     
  7. r_dawson12

    Thread Starter New Member

    Jul 27, 2013
    7
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    This may be too much to ask, but how would one determine approximately how long the 8 AA would last powering the fan?
     
  8. LDC3

    Active Member

    Apr 27, 2013
    920
    160
    How much current does the fan draw? What type of batteries are you going to use (carbon-zinc, alkaline, NiCad, NiMH, Lithium)?
    http://en.wikipedia.org/wiki/AA_battery
     
  9. r_dawson12

    Thread Starter New Member

    Jul 27, 2013
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    I was thinking either alkaline or NiMH. I'm not really sure about the fan - I guess I have some more research to do :)
     
  10. wayneh

    Expert

    Sep 9, 2010
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    The fan spec said 10mA. A typical AA might be 2500mAh, so would run the fan for 250 hours! (Putting them in series does not add capacity, just voltage.)
     
  11. odinhg

    Active Member

    Jul 22, 2009
    65
    15
    On the webpage for the fan it says 10mA under specifications, but on the picture of it, it shows 100mA (0.1A). For me, 100mA sounds more realistic than 10mA.

    In that case it would be what wayneh said, but divided by 10. That is 25 hours theoretically.
     
  12. wayneh

    Expert

    Sep 9, 2010
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    I agree that 100mA is much more believable. You need the energy to move the air.
     
    odinhg likes this.
  13. r_dawson12

    Thread Starter New Member

    Jul 27, 2013
    7
    0
    Awesome. Thanks for the responses/help!
     
  14. NFA Fabrication

    Member

    Aug 12, 2012
    104
    3
    I look to use a 3 cell lithium battery typically used in RC cars. pretty cheap these days (Under $40 with a charger for a 5000mah probably), and will run your set-up much more cost effectively.

    Battery: http://www.hobbyking.com/hobbyking/store/__9184__Turnigy_5000mAh_3S_20C_Lipo_Pack.html

    Charger: http://www.hobbyking.com/hobbyking/store/__9184__Turnigy_5000mAh_3S_20C_Lipo_Pack.html

    I have personally used this charger and battery, they work great. I power all my battery operated projects with RC lithiums. 3 cell batteries like these are great for 12V projects, 12.6V full, and about 10V when needing to be recharged.
     
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