I would like to know if I am able to use a 45W MagSafe Power Adapter in my MacBook Pro Retina 15 with a MagSafe to MagSafe 2 Adapter.

I am normally using the original one (85W MagSafe 2 Power Adapter) but I just want to know that the computer will charge correctly and that the battery won't be hurt.

3 Answers 3


It will charge. However, it will do so very slowly.

  • agree - it may, in fact, not keep up if the machine is in heavy use.
    – Tetsujin
    Commented Mar 13, 2015 at 19:29
  • only good for overnight use
    – Ruskes
    Commented Mar 14, 2015 at 2:16
  • The other thing to bear in mind will be heat - I've used the charger for my 13 inch MacBook with my 15 MPB - it works, but gets very warm. I suspect this will decrease the life of the charger as well. Commented Mar 16, 2015 at 20:34

I am using the original apple 45W charger from my old MB Air with the magsafe 2 adapter on my MBP 2016 and I haven't had any problems in the last 2.5 years.

  • Did you use the 45W on 13' or on a 15' MBP ? Thx
    – A.G.
    Commented Jun 13, 2022 at 7:35

I've been using the MacBook Air 45W power adapter with my MacBook Pro Retina 15" and it works perfectly. Charging takes a little longer than with the original power adapter. I recommend the 45W adapter for travel.

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