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Electronics Getting 10 Volts From USB?

Discussion in 'Modding' started by Seraphim Works, 1 Jul 2007.

  1. Seraphim Works

    Seraphim Works What's a Dremel?

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    Hey guys, first time post after lurking for god knows how long.

    Just a quick question really, I'm looking at running an 80mm fan, namely this one http://www.nexustek.nl/80mm_real_silent_case_fan.htm. However I want to run it at 10v, and seeing as the motherboard I'm using only has 5v fan headers, usb seems a possible solution.

    Is it possible to create a 10v line for a fan using two usb ports, and somehow connecting them in series to get 10v from the two 5v lines? Or is this idea doomed to failure from the start?
     
  2. teamtd11

    teamtd11 *Custom User Title*

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    I would of thought the best option would be to cut the line into the fan and place a resistor in, to take the 12V down to 10.

    it soulds like it should work from usb, but its not something i would want to try for some reason:hehe:
     
  3. capnPedro

    capnPedro Hacker. Maker. Engineer.

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    Are you sure? That sounds very strange. What motherboard is it?
     
  4. Butcher9_9

    Butcher9_9 What's a Dremel?

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    you got it totally wrong

    you add resistors to reduce voltage relative to the source of the power and not the thing being used
    http://www.xs4all.nl/~odu/dcdc.html
     
    Last edited: 1 Jul 2007
  5. Seraphim Works

    Seraphim Works What's a Dremel?

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    The motherboard is from a laptop, hence the 5v headers, I'm stripping it down for a project I'll be working on during the summer, and I have some ideas for the cooling system. But in order to make it work, I need enough volts to drive a decent fan. Hence the need for at least 7v, preferably 10v.
     
  6. capnPedro

    capnPedro Hacker. Maker. Engineer.

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    Ah.

    There may be a 12v line available from the laptop's PSU. this would probably be easier to tap than using a DC-DC converter. The backlight's inverter should have a 12v input.
     
  7. cpemma

    cpemma Ecky thump

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    The hard/optical drives' supply leads may be easiest to tap.
     
  8. Moriquendi

    Moriquendi Bit Tech Biker

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    I thought laptop drives only used 5V.

    How do you plan on powering the thing? if youre using the laptop AC adapter/charger you should have somewhere between 15v and 20v DC available to you where it plugs in, you could drop that down to whatever you like using a resistor/regulator.

    Alternativly you can get 5V fans or there are some 12v fans that will run on 5V.

    Moriquendi
     
  9. Seraphim Works

    Seraphim Works What's a Dremel?

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    Hmm, I never thought to tap into where the 19v comes in from the adaptor, I might give that some thought, just need a multimeter to be honest to make sure I'm tapping into the right bits.

    Well, it'll be practice with the soldering iron at least....
     

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