12v PC Case Fans running on a TV

Discussion in 'Electronics & Electrics' started by MdMa, Nov 30, 2017.

  1. MdMa

    MdMa Member

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    I would like to get some case fans mounted on my TV.

    I could use a molex to USB adaptor into the TV's USB ports, but this will of course reduce the fan speed.

    How can I have multiple fans running at their full speed?
     
  2. rthy

    rthy Member

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  3. oculi

    oculi Member

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    how noisy do you want your TV? why does it need fans? you could try to find a 12 volt source somewhere or just run them off a 12 volt plugpack.
     
  4. MonoJoker

    MonoJoker Member

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    I ran fans in my shed data cabinet off a dedicated PC PSU. Not knowing the full details of what you're doing or how ghetto a setup you can handle, that might work for you too. Personally I had the PSU doing nothing (so total cost was free) and it obviously doesn't need to be very high Wattage to run a couple of fans.
     
  5. OP
    OP
    MdMa

    MdMa Member

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  6. MonoJoker

    MonoJoker Member

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  7. OP
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    MdMa

    MdMa Member

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    The TV is already somewhat noisy (Plasma), and gets very hot, hence my need/want of some fans.
    The TV also has a well documented fault, so I am hoping to prolong the inevitable with these fans.

    The plugpack as mentioned above may not be suitable.

    This might be the best option... or I could just run them at the lower 5v USB voltage and see how they do...

    Thanks for the input everyone.
     
  8. OP
    OP
    MdMa

    MdMa Member

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  9. ipv6ready

    ipv6ready Member

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    In an open air environment you wont need much flow.
     
  10. OP
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    MdMa

    MdMa Member

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  11. oculi

    oculi Member

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    figured as much but you never know.

    why not?

    every 12 volt fan I've ever met will happily run on 5 volts.

    bit OT but I'm pretty sure my 40 inch Samsung LCD has a fan/s in it
     
  12. ipv6ready

    ipv6ready Member

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    120mm 2000 rpm fans and lower will definitely run of 5v.

    I used to run one 12v 120mm 2000rpm el cheap fan in a closed TV cabinet to cool my HTPC via usb2.

    There was couple of 50mm port holes in the back and gaps on the glass door to move enough air to drop cpu temps at from 60c to 40c watching h264

    That one fan running meant that it actually turned by HTPC silent, literally

    https://www.ebay.com.au/itm/USB-2-0...hash=item48a22dee8f:m:mnMrKFe6Vs8eKgAtOAUE5Ag

    https://www.ebay.com.au/itm/USB-To-...774701&hash=item2a76e0b481:g:x0cAAOSwcUBYSSxI

    Also by just cutting and reattaching wires, you can run some off old phone 5v chargers
     
    Last edited: Dec 1, 2017
  13. merlin13

    merlin13 Member

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    Honestly the first thing I'd suggest here is rather than band-aid that problematic plasma TV is shit-tin it (especially with summer now here) and go find an LCD one At The Right Price - last two 32" ones I've acquired cost me $5 and $10.

    Or forget mucking about with adding cooling fans to it and simply go grab yourself a normal pedestal fan (like this) and have it push air beside/behind the TV and over you as well. Last time I wandered past a K-Mart they had 'em for $15, or $25 with a remote control...


    If you can't/won't go for these suggestions then make yourself comfortable and read on.

    For full speed you'll need to feed them 12 volts - first rule of PC Fan Club. :leet:

    Standard USB port(s) will only give you 5 volts at limited current, so if you want to run multiple fans at full speed then also forget even thinking about running a step-up power supply (+5 in, +12 out thingy). You'll be looking at a plugpack or PC supply etc for an external power source.

    Could always drag a car battery inside at use that, that'll work for a while... :)

    For multiple fans in parallel read this, look at this (ignore the voltages and diodes, too lazy to find a better image...).

    And if you need to force-feed cooling air into a hot plasma then rethink your multiple fans and look at a small single fan pushing air into the innards in sane manner. Work out where the hot spot(s) is/are (put your hand on the back of the screen and feel around) then have the fan push air up into the bottom cooling slots past that/those.
     
  14. power

    power Member

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    i have a panasonic plasma and while it runs a little warm the 3 fans do a good enough job - don't forget they are built to spec. just make sure that it's getting airflow around it and you should be fine.
     
  15. OP
    OP
    MdMa

    MdMa Member

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    After a little more reading.. it may be suitable.

    So if my fan consumes 0.12A and the molex power supply that was linked earlier has an output of 2.5A... I'm guessing I can daisy chain a few fans together?
     
  16. merlin13

    merlin13 Member

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    Noooo, if you daisy chain them the voltage across each one drops - two 12 volt fans in series means each fan only gets 6 volts. Three in line means 4 volts each... Two fans in series will chug along quite nicely at slow speed, but three probably won't even run at all.

    For full speed you need to put then in parallel - connect all the red wires together, then connect all the black wires together. Each fan then gets the full 12 volts, but the overall current draw is added together, ie if each fan is rated at 0.12 amps then two fans need 0.24 amps, three need 0.36 amps and so on. That power supply at 2.5 amps maximum will run oooooodles of those fans.

    And if you're only looking at 0.36 amps or so maximum at 12 volts, then unless you want to run some pretty lights in behind the TV or enough fans to levitate it as well, pick up a 12 volt 500mA (aka 0.5 amp) plugpack - lots smaller and should be cheaper...
     
  17. mike-s

    mike-s Member

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    I definitely agree about the plug pack idea. As to the fans, have you considered getting some slim blower units? that way you could get a directional flow going rather than drawing air in and having it hit the motherboard and just going everywhere and potentially not really helping..
     

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