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    Options for 12v access

    Discussion in 'Sager and Clevo' started by SnowDrifter, Jun 5, 2018.

  1. SnowDrifter

    SnowDrifter Notebook Geek

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    Upgraded my cooling pad when the original fans went out. Using some of the noctua industrial 3000rpm fans for it running through a fan controller. The controller needs 12v through a molex adapter. Currently using a separate power supply for it but I was wondering, for the sake of ease of usability, are there any easy options for getting 12v at 0.75-1amp directly from the computer?

    Iirc USB 3.0 is 5v. It has an esata port as well as a quick charge USB port on there. Would either of them work for my purposes?

    I know I could do some custom wiring inside the computer but I'm really not willing to go that far. Just checking if there are any options sans power brick
     
    SnowDrifter, Jun 5, 2018
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  2. Chastity

    Chastity Company Representative

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    There are 5v to 12v inverters, however, there's still a loss of potential. You may be able to do .5 A @ 10v at best from USB3.
     
    Chastity, Jun 5, 2018
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  3. senso

    senso Notebook Deity

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    Getting a stable 12v out of 5v is easy with a boost regulator.

    But given that it would be only pulling power and nothing else, and to avoid problems you should limit the load to 500mA at 5v, that gives 2.5Watts.

    With 12v out, and a 90% efficient boost reg(not that hard to do, even with a TI simple switcher), thats 2.5/12 * .90 = 0.185A.

    If your fans draw less than that..

    It wouldn't surprise me that drawing 1A from the USB port is possible and the mobo wont complain, so that leaves us with an initial 5Watts, and thus, 5/12 * .90 = 0.375A, a bit more headroom, but I would call it still tight.
     
    senso, Jun 5, 2018
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  4. SnowDrifter

    SnowDrifter Notebook Geek

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    The fans themselves are 3.6w a piece and I have 2. Would need 7.2w plus a little bit of fudge factor for what the controller takes
     
    SnowDrifter, Jun 5, 2018
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  5. senso

    senso Notebook Deity

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    If you dont need to run them at full blast, you can PWM them to reduce the speed and thus power usage.

    Another option would be using a DC-IN connector and a piece of cable with male part, and make a small pcb with a buck regulator that makes 12v out of the 19v from the charger and connect charger to adapter board, adapter board plugs to laptop.
     
    senso, Jun 6, 2018
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  6. Support.3@XOTIC PC

    Support.3@XOTIC PC Company Representative

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    Sounds like more trouble to get working than it would save over just plugging into the wall to me, though you could probably do it with an inverter.
     
    Support.3@XOTIC PC, Jun 6, 2018
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  7. senso

    senso Notebook Deity

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    If OP likes electronics its a nice weekend project.
     
    senso, Jun 6, 2018
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  8. Meaker@Sager

    Meaker@Sager Company Representative

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    There is no 12V rail so you would have to create it really.
     
    Meaker@Sager, Jun 6, 2018
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