Can I power my Macbook with my Ipod Charger Via USB or Firewire?

Discussion in 'MacBook Pro' started by azza, Feb 2, 2008.

  1. azza macrumors newbie

    Joined:
    Feb 2, 2008
    #1
    Now this may seem like a silly question but I am a bit desperate.

    My Macbook is flat and I need to do some work.

    however I left my magsafe charger at work and can't get in until monday.

    So how can I power my macbook?

    any suggestions?

    I thought maybe I could plug in my ipod charger into the usb port or firewire.

    Does anyone know if that will completely stuff things?

    :D
     
  2. McGiord, Feb 2, 2008
    Last edited: Jan 30, 2011

    McGiord macrumors 601

    McGiord

    Joined:
    Oct 5, 2003
    Location:
    Dark Castle
    #2
    No way you can re-wire your mac internally to use you USB or Firewire as a power source to your mac.

    I think is time for you to buy a spare power adapter, so you keep it in your car/home to avoid going through this issue again.
    ________
    digital vaporizers
     
  3. motulist macrumors 601

    motulist

    Joined:
    Dec 2, 2003
    #3
    I'm not so sure about that. When I briefly looked at the mba at the apple store, it only had a single cable connected to it. This only attached cable was connected to the usb port, but the on screen menu bar power graphic showed the 'power is plugged in' icon (iirc). The cable had a little boxy thing where it attached to the mba with a security warning sticker about disconnecting the cable, it had a red LED light on it, and an open USB port on the other end so you could still access the USB port when this plug was attached to the mba's usb port.

    So if I'm remembering correctly, the MBAs at the apple store are indeed getting powered via the usb port.
     
  4. robbieduncan Moderator emeritus

    robbieduncan

    Joined:
    Jul 24, 2002
    Location:
    London
    #4
    They are not USB powered. The magsafe adaptor plugs in in such a way that you would not see it unless you picked the machine up: it doesn't stick out the side like other mac notebooks.
     
  5. skyrider007 macrumors 65816

    skyrider007

    Joined:
    Aug 5, 2007
    Location:
    Bangkok
    #5
    but he said there was only one cable connected to it. i'm sure the power cable can't be that discreet.
     
  6. robbieduncan Moderator emeritus

    robbieduncan

    Joined:
    Jul 24, 2002
    Location:
    London
    #6
    Depends on the display setup. The cable attached under the left side, out of sight and runs from there directly towards the back of the machine. There is plenty of space for that cable to then go into a whole in the display surface and "disappear".

    It's certainly not possible to provide the 45W that a Macbook Air charger can supply over USB: it's rated to a max of 500 milliamps @ 5V (2.5W). Now although we know the Air can provide more than this to certain periferals (which is why the air superdrive won't work on other machines) the USB plug and associated internal cabling certainly are not going to be rated to 18 times the max allowable power of USB. This ignores the fact that USB is designed to supply power, not receive it so USB controllers do not have the required voltage regulators and smoothing capacitors with them to provide a steady input voltage to the delicate internal circuitry of a modern computer.

    So in short: no chance.
     

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