Will my spare 45 watt power supply work

Discussion in 'MacBook Pro' started by rpg51, Feb 25, 2013.

  1. rpg51 macrumors 6502


    Jul 4, 2012
  2. Daniel L macrumors 6502

    Sep 15, 2009
    If it's an older one for the previous gen Macbook Airs you'll need a Magsafe to Magsafe 2 adapter. It will work for powering it but if you put a load on the system it might stop charging because the adapter can't put out enough current.
  3. AlphaDogg macrumors 68040


    May 20, 2010
    Boulder, CO
    No. It won't put out enough current to power your computer. I'm running my 15" MBP off of a 60w magsafe charger, and if I take out the battery, the MBP doesn't boot with just the charger connected. This computer needs an 85w charger. It charges slower with the 60w and uses both the battery and charger to power the computer (slowly decreases battery charge while I'm using it). I could only imagine what would happen if I tried a 45w.
  4. chrise2 macrumors 6502

    Sep 17, 2012
    I have the 45W adapter from my old Air and it works with my 13" retina. I try not to use it while connected to the charger and only use it to charge the laptop while its in sleep mode to not tax the charger too much. You need the $10 adapter for it too like someone else said.

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