Are Apple's power supplies interchangable?

Discussion in 'MacBook Air' started by Wolfpup, Jul 29, 2011.

  1. Wolfpup, Jul 29, 2011
    Last edited: Jul 29, 2011

    Wolfpup macrumors 68030

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    #1
    Apple's got a 90, 60, and 45 watt PSU for their various notebooks (unless they have larger I'm not aware of).

    And...all three cost the same price.

    I'm just wondering-are they interchangeable? Like a system that comes with a 45, can it use a 90? Or a 60 a 90?

    I'm just thinking if they're all compatible, there would seem to be no reason for me to buy a 45 watt PSU for an air (or a 60 for a 13" Pro) if the 90 works, as then I might be able to use the 90 on more systems down the line?

    EDIT: Sorry, I should clarify that I know I shouldn't use a smaller one to power a larger one, but I was hoping it was okay to use a larger one to power a smaller one, if that makes sense. Wasn't sure if Apple used the same connector, or was doing something else weird, but it sounds like they're all the same, so you can buy a 90 for the Air or 13" Pro!
     
  2. GoCubsGo macrumors Nehalem

    GoCubsGo

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  3. Intell macrumors P6

    Intell

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    #3
    You can use an 85W to charge an Air. But cannot use a 45W to charge a 17" Macbook Pro. It will not damage the Macbook in anyway to use a higher rated wattage, but they should not be used with a lower rated wattage.
     
  4. HellDiverUK macrumors 6502

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    #4
    Yes.
     
  5. wpotere Guest

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    #5

    What this guy said, not the poster above me.
     
  6. onthecouchagain macrumors 604

    onthecouchagain

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    #6
    My understanding is you can go one way, but not the other. And if I have it right, you can go higher to lower, but not lower to higher. Meaning, you shouldn't use the 45 to charge something that requires 60. But you can use the 60 to charge something that only requires 45.

    Please correct me if I am wrong. This is my understanding, but I don't want you to ruin anything because of my misinformation.
     
  7. Wolfpup thread starter macrumors 68030

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    #7
    Cool, thanks! I'm semi-confused by why they bother selling the lower wattage PSUs then if they charge the same price, but thanks to you guys I'll just buy a 90! :) (Or an 85 I guess? Whatever the largest one is)
     
  8. HellDiverUK macrumors 6502

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    #8
    They're all interchangable. The lower wattage ones just take longer to charge a higher power laptop.

    As the OP is looking to buy a 90W one, it'll work on all Apple laptops using MagSafe.

    So, the answer is still yes.
     
  9. Intell macrumors P6

    Intell

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    #9
    The higher wattage ones get hotter, use more power, and are probably more expensive to make.
     
  10. maril1111 macrumors 68000

    maril1111

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    #10
    um not entirely you can charge a laptop that needs a higher wattage charger i.e 85 watts with a lower wattage one but only if there is still charge in the battery and the battery is not completely drained. I have read it somewhere in the apple support discussions.

    Official Apple Article quote :

    http://support.apple.com/kb/HT2346
     
  11. Wolfpup thread starter macrumors 68030

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    #11
    Could get hotter...but only if they're drawing more power. Can use more power, but not really when connected to an Air or 13" Pro.

    I mean PSUs tend to have loads under which they're most efficient, and maybe say the 60 watt one is the most efficient when powering an Air, or something...but I'd have to actually buy them all and test that, and it could be the 90 watt one that's most efficient for all I know, and I doubt it's a huge difference :)
     
  12. xraydoc macrumors demi-god

    xraydoc

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    #12
    The 45 watt unit is much smaller/lighter than the 85 watt model that comes with the 17" MBP and higher end 15", and a bit smaller than the 60 watt.
     
  13. Intell macrumors P6

    Intell

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    #13
    I thought they where different sizes. Wasn't quite sure. I guess you can add "shipping costs" to the list.
     
  14. Wolfpup thread starter macrumors 68030

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    #14
    Still tiny though. Wouldn't be an issue for me even if I carried it...which I don't, because I leave one at home, and one at work, which makes it much faster to just throw my PC in my bag, and faster to hook up too.

    I still think maybe I'll need a 15 or 17" Pro though so I must get the larger PSU :D
     
  15. onthecouchagain macrumors 604

    onthecouchagain

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    #15
    Is there a difference between the 13" Air charger and the Pro 15" charger? Just wondering.
     
  16. Wolfpup thread starter macrumors 68030

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    #16
    Yeah, the Air comes with a 45 watt PSU I think, and the 15" Pro comes with a 60 or 90 watt PSU, but you can use the 90 watt one on systems that ship with 60 or 45.
     

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