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Recharging Laptop From Plane Headphone Jacks?

Posted by Cliff on from the is-there-enough-current-for-the-job dept.

krow asks: "So every flight I get on I wonder, could I partially recharge my laptop off of the headphone outlet? What about using alligator clips to the recharger for the airphone? Anyone else have some creative ideas? How much juice do you think you could pull before tripping a breaker?" Well, this was a fun question for once. I've always wondered the same thing but figured the current/voltage would be insufficient for anything more than a trickle charge, if even that. Anyone have any clues? Or better yet ... anyone have alligator clips for those wacky Airphones?

7 of 19 comments (clear)

  1. Headphones no, other chargers maybe. by Christopher+Thomas · · Score: 3

    Trying to pull that much power from a headphone jack would probably blow the buffer or amplifier that's on the other end. The headphone jack on your typical sound card, for example, is only specced to about 4 watts. Your computer consumes much more power than that, and the power consumption for charging will be comparable to this or greater than this (unless you want to spend far more time charging than using).

    OTOH, if they wired the headphones the cheap and crappy way (in parallel), you can pull a fair bit more power without damaging anything... as long as nobody else is trying the same stunt. YMMV. I wouldn't risk it.

    An outlet that's specifically designed for charging other devices might be more practical, but bear in mind that something like an airphone probably has lower power consumption than your computer, and the charger will thus be specced for lower power on charging (no reason to charge it faster than, say, 4x usage power consumption [random figure]).

    Lastly, if you have a power converter in your charger (as is likely), you'll probably be producing a lot of RF noise during charging (as most compact power supplies/power converters are switched at high frequency to let you make inductive components smaller).

    My advice: Shell out for an extra battery.

  2. Warning, bad pun by stubob · · Score: 3

    But don't all Slashdotters get aisle seats because they hate Windows?

    -1, groaner. The current moderation system is boring.

    --
    Planning to be moderated ± 1: Bad Pun.
  3. Of course it is. by Alik · · Score: 2

    At least, it is for my laptop. If you happen to have a Dell, try here for some options. Other manufacturers, ask your OEM.

    1. Re:Of course it is. by MemRaven · · Score: 3
      The jacks that those will work with are specific recharging ports available on some airlines. Specifically, I've NEVER seen them in coach. In business class on international flights, I see them all the time. But even First Class on domestic flights seldom have them (flights are too short to make them that worthwhile, and they haven't upgraded the seats up there to the seats they can charge an extra $5k for).

      The specific question is whether you can charge your laptop on something which was not designed for it, and probably something you're going to find in Coach class.

  4. Airplane Power Jacks by SEWilco · · Score: 2

    The EmPower jacks on airplanes are 15V, not 12V. Web searches for "airplane power notebook" will show you many manufacturers of power adapters for those jacks. Or use an EmPower-to-12V adapter with your notebook's car adapter.

  5. You cheap bastard! by Spackler · · Score: 2

    Buy an extra battery. I'm not sure about anyone else, but I don't think I want you ripping into panels with alligator clips digging into the electrical system of a plane that I'm on. Call me a wimp.

    Two batteries will get you across the country on just about any modern laptop.


    http://www.superiorlabs.com

  6. Lessen the need by jfunk · · Score: 2

    I have my laptop set up not to suspend when I close it. The screen will turn off, though. I get an extra hour or so listening to MP3s.

    You could also decrease power usage by removing PCMCIA cards.

    Also, if you have the patience, set up a RAM disk and store MP3s there. Then set it up so that the hard disk isn't used so much (look for cron jobs, and see the Battery-Powered HOWTO). Set up APM to power down the disk quickly.