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Question: Can laptop run off 12v deep cycle battery?

Discussion in 'Electronic Basics' started by shrdlu, Jun 12, 2008.

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  1. shrdlu

    shrdlu Guest

    On the road, a Dell laptop's AC-to-DC adaptor is powered by a 75W
    inverter plugged into the car's cigarette lighter recepticle. Is there
    any way aboard a small boat (using Radio Shack parts) a direct power
    supply from 12v deep cycle battery to computer can be rigged up
    without utilizing the inverter and the charging capabilities of the
    Dell power brick? Default DC to the computer is 19.5V - 3.34A
  2. James Beck

    James Beck Guest

    Anything is possible, if you want to throw enough money at the problem.
    Why not get one of those rechargeable power boxes that has the inverter
    built in and use it to power the 'brick'? That way you can use it for
    MORE than just your laptop.
  3. IanM

    IanM Guest

    The inverter/PSU combination offers valuable isolation from surges and
    other transients and will minimise the risk of expensive damage to the
    laptop. Depending on the model, either Dell or a third party supplier
    may offer a DC-DC converter that replaces the AC PSU for in vehicle use.
    The difficulty of designing and building a 65 watt switching converter
    should not be underestimated. With the added risk of frying the laptop,
    I wouldn't even consider building one as a one-off.
  4. James Beck

    James Beck Guest

    Um, where did I say ANY of that?

    I am referring to a COTS unit that can be picked up in most
    automotive/travel stores.
  5. Guest

    Wow, those ARE nice!

    I can imagine one with a yellow "radiation hazard" sticker on it...
    that would sell well for college kids...

  6. Guest

    Or for a DIY solution, two 6V, 7A-hr batteries in series (Home Depot
    has 'em in the lighting section, about $20 ea.) plus a 100W 12VDC
    inverter. Throw in a pretty box (with radiation hazard logo!) and a
    9VDC wall-wart (to charge the batteries - don't ever exceed 15V!!) and
    you're in business.

  7. terryc

    terryc Guest

    Really not worth the effort. Far easier just to go with inverter and use
    existing plugpack. unless there are particular reasons, aka multi-day
    run times when you are going to be saving significant battery weight.

    If you are serious, just series two 12V batteries and regulate the voltage
    down to match the laptops requirements. Alternatively, try 3 x 6V deep
    cycle bateries in series, if that is enough. does the lappie have an
    internal removeable battery? Is it the normal 12V? Then 18V direct should
    suffice. you just have to over come the loss in the internal battery
    recharger circuit.
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