Results 1 to 15 of 15
Like Tree4Likes
  • 2 Post By SmokeyMacPot
  • 1 Post By ChicagoJoe
  • 1 Post By Giantsfan24

Thread: How do I power 12v computer fans?

  1. #1
    420 Member SmokeyMacPot's Avatar
    Join Date
    Jan 2004
    Posts
    3,175

    How do I power 12v computer fans?

    Quiet, low power and surprizingly efficient, computer fans are an ideal cooling option for smaller cabinet grows. The only problem is that most computer fans are 12v and not 120v! How do I run a 12v fan on normal household power?

    # Computer power supply
    (A 145 watt computer power supply is over-kill for a 5-20w fan. Try for something small, like a 75watt or 100watt supply). You could drill holes and mount the power supply inside your cabinet. turn the power supply on and off with the power switch on the back.

    # (Carpe-Nox) … if you have any old cell phone chargers around, they use 12v, same that a pc fan uses, just splice the pc fan wires

    # [Editor’s note: 120v computer fans can be found. Add a pigtail to your fan and voila.]

    Fan ideas
    Computer Cables, Computer Parts, Computer Accessories, Computer Adapters, PC Components

    ex.) 120mm, 90CFM fan for $11.95. it only uses 5.4 watts - a perfect exhaust fan.

    ex.) 80mm computer fan that is thermally controlled. $5.95 - the hotter your cabinet is, the faster it spins.

    (Jakestone) PCs frequently run their 12V fans at voltages below 12. 7 Volts is very common. Much below that, there can be an issue of having enough starting voltage to get the fan going. The volume of air being moved is reduced, but so is the noise.

    (Jakestone) El cheapo $3 fans are often significantly louder than better fans (say 5+ db) and have a dirtier sound (less whoosh and more whine/ticking). High-end fans generally go for between $10 and $15. Computer power supplies are notoriously noisy (especially cheap ones).

    (Jakestone) In general, a larger diameter fan moving a given amount of air will be quieter than a smaller diameter fan moving the same amount of air. So for example, one might buy a 120mm fan that moves more air than you need to move at 12V and run it at 7V instead of running a 80mm fan at 12V. The downside for cabinet growers might be the need to light-baffle a larger hole.

    Author: usr, share, bong and JakeStone
    Weeden and Mr Ganja like this.

  2. #2
    420 Member
    Join Date
    Sep 2009
    Posts
    877

    Re: How do I power 12v computer fans?

    Here's a Fan controller specifically for pc fans. The controller has a power adapter that plugs in the wall and the 12v PC fans plug directly into the controller to get power. $26 Silenx IXAFCEX Four Channel External Fan Controller at TigerDirect.com



    I recently purchased and installed this fan controller.
    Pros:
    Unit plugs into wall.
    Runs up to 4 fans all controlled individually.
    PC fans plug directly into the unit.

    Cons:
    Wires from fan controller are only about 2' long.
    Blue indicator lights might cause problems in flowering cycle (I used black electrical tape over the LEDs)
    Last edited by Cozmo; 02-05-2010 at 09:18 PM. Reason: fixed photo

  3. #3
    New Member BangMaster's Avatar
    Join Date
    Feb 2010
    Posts
    2

    Re: How do I power 12v computer fans?

    Very good tip, I will probably purchase one of them plus 4 80mm fans for my new cabinet I am building.

  4. #4
    420 Member
    Join Date
    Sep 2009
    Posts
    877

    Re: How do I power 12v computer fans?

    Quote Originally Posted by BangMaster View Post
    Very good tip, I will probably purchase one of them plus 4 80mm fans for my new cabinet I am building.
    After hooking these up, I was impressed with it.
    2 things though -

    1. there are blue l.e.d.s that need to be cut or covered if the unit is in the grow area.

    2. I bought 80 mm fans, but I'm wishing I got the 120mm fans with more cfm.

  5. #5
    New Member BangMaster's Avatar
    Join Date
    Feb 2010
    Posts
    2

    Re: How do I power 12v computer fans?

    Thanks.
    I saw that they sell also the fan screen with a filter inside. I am wondering if I can replace it with a carbon filter and use these fans for exaust the odor as I am planning to grow with LED PPF 400 so I won't have the heating problem but it's really important for me the odor and the noise.
    What about the noise of these fans? Are really noisy the 80mm?
    Finally, do you keep them running 24h when you do the 12/12?

  6. #6
    420 Member Stoned Redneck's Avatar
    Join Date
    Aug 2009
    Location
    N.W. washington state
    Posts
    297

    Re: How do I power 12v computer fans?

    a person could go to goodwill ect. and get a bag of plug in chargers,like from cell phones,radios.you know, small black things that plug in with a long plugin.anyway just check and be sure it has 12 volt OUTPUT and you should be fine.12 volt is easy to work with as it wont shock you like 120 volts.it will sure spark but won't bite. so check it out i have a sack full of them from old phones ,tool charger ect.i'm a pack rat as well.hope that made sence and helps. c u,todd doh!! sorry for the re-run .i need to slow down and Read the whole story before i add my 2 bits worth... sorry....
    Last edited by Stoned Redneck; 02-08-2010 at 10:21 PM. Reason: jumping the gun and not reading the whole thing...
    God Bless America !!!

  7. #7
    420 Member
    Join Date
    Sep 2009
    Posts
    877

    Re: How do I power 12v computer fans?

    Quote Originally Posted by BangMaster View Post
    Thanks.
    I saw that they sell also the fan screen with a filter inside. I am wondering if I can replace it with a carbon filter and use these fans for exaust the odor as I am planning to grow with LED PPF 400 so I won't have the heating problem but it's really important for me the odor and the noise.
    What about the noise of these fans? Are really noisy the 80mm?
    Finally, do you keep them running 24h when you do the 12/12?
    The 80mm computer case fans are very quiet. The only sound is the air whooshing, and at 42cfm, they are quiet. I think it is recommended to keep the fans on 24/7.

  8. #8
    420 Member Giantsfan24's Avatar
    Join Date
    Nov 2010
    Posts
    1,039

    Re: How do I power 12v computer fans?

    I couldn't help chiming in here as I found a great site with fans, filter screens for them, the centrifugal fans (that's what I need), anti vibrations mounts...

    All kinds of stuff we might need for a quiet running exhaust system. I'm going to use the centrifugal blower with a home made, chicken wire carbon filter in addition to a carbon filter behind the filter screen. Noise will be low and hopefully I'll be over compensated for smell..

    Here is the link..

    Computer Case PC Cooling Fans at SVC.com

    I don't have any experience growing yet, just researching the box build. Thought this might be a great place to go.

    C H I C A G O - how did you get around the 2' wires from the controller?
    Thanks!
    olypenn likes this.

  9. #9
    New Member
    Join Date
    Dec 2010
    Posts
    1

    Re: How do I power 12v computer fans?

    I replaced some 4" AC fans with the 120mm PC fans, much smoother sounding and quiet. I just used an old AC adapter and a single PC fan speed controller.

    About the same flow IMO.

  10. #10
    420 Member
    Join Date
    Dec 2010
    Posts
    50

    Re: How do I power 12v computer fans?

    just use simple 12 transformer and will be ok

  11. #11
    420 Member DrTentgrow's Avatar
    Join Date
    Apr 2009
    Posts
    856

    Re: How do I power 12v computer fans?

    If you have a spare unused transformer cut the end of it, it should have a one black wire and one black wire with a white stripe, wire the red wire of the computer fan to the wire with the white stripe and the black to black wire.

  12. #12
    New Member Son of Adam's Avatar
    Join Date
    Dec 2011
    Posts
    10

    Re: How do I power 12v computer fans?

    I almost bought a pc power supply to operate the fans, the cell charger is a better idea, so is the transformer.

    Thank you all for the tips

  13. #13
    420 Member
    Join Date
    Feb 2012
    Posts
    114

    Re: How do I power 12v computer fans?

    http://www.canadiantire.ca/AST/brows....jsp?locale=en

    here's a cheap item that, could do the trick if used right.

    Question: Once the furnace stops blowing, does this fan still keep going? If so, it would end up sucking in cold air (in the winter). Or is it designed to shutoff once the furnace stops blowing?

    Answer: If it's set to the auto function, it will turn off when the furnace fan shuts-down. There is also a "Set Point" control that adjusts sensitivity.

  14. #14
    New Member Degauss's Avatar
    Join Date
    Mar 2011
    Location
    Santa Cruz
    Posts
    22

    Re: How do I power 12v computer fans?

    A couple of notes on using muffin fans. Muffin fans work great if you get a good one. I actually have one on one of my older non air cooled hoods... it whisks air out of the light so the huge fan can take the heat out, and that means the canopy is a bit cooler!

    POWERING: You can actually source muffin fans that plug right in to the wall- audiophiles have used them to cool their gear, but these are more expensive than getting 12v PC fans and using either a computer power supply or a 12v power supply (like I do- I have a less fancy version of the fan speed controller that ChicagoJoe posted in 2010).. I feel the old cell phone charger method is more prone to danger even though a 12v line won't fry you.

    NOISE: Since we can opt for a cheapo PC fan, we have to be careful not to go TOO cheapo, since cheap fans use inferior ball bearings, making them noisy and prone to breakdown. A good, quiet, and not too expensive brand is "Noctua"

    It is a bit counter-intuitive, but the larger the fan, the less noise it makes while moving more air! I ended up getting about a 4" model, since my old hydrofarm hood has a vent exactly that big, but a 92 or 120mm would be way quieter.

    In the quest for quiet, you will want to install little rubber grommets that act as sound dampeners, or suspend the fan from rope or something. For a cabinet, use rubber insulation around the fan to reduce noise.



    LIGHT:
    As was mentioned, make sure you get a light without the obnoxious useless LED- it's shocking that more fans nowadays seem to have LED's than don't.
    Last edited by Julie Gardener; 02-26-2012 at 10:23 AM. Reason: guidelines

  15. #15
    420 Member
    Join Date
    Aug 2012
    Posts
    265

    Re: How do I power 12v computer fans?

    I found a model train/railroad power packs are great for powering 12VDC fans. they are basically DC variable voltage regulars output is around 0-18VDC. this allows you to control the speed too some like the one I use also have 12VDC and 18VAC hook ups for lights etc around the tracks that could be of use too.