Can you use the 65w MacBook Power Adapter with an 85w MacBook Pro? - Macenstein

Can you use the 65w MacBook Power Adapter with an 85w MacBook Pro?


(Disclaimer – This was
my experience, if you try this and blow up your laptop or house, it’s your fault).

I only post this because I could not find any definitive answer when Googleing last night, so I figured I would share my experience. When I got home last night, I realized I forgot my new MacBook Pro’s (Nov 2008 / unibody) power supply at Macenstein‘s labs, but I really needed to work on some award-winning articles. Once my MBP’s battery hit 37%, I began to panic (btw, there’s no way the new MacBook Pro gets close to 5 hours of battery life, even with the performance turned down). I looked around and noticed I had an extra power supply for my (October 2007) white MacBook lying around, so I figured, “What the hell, they both have MagSafe connectors! Let’s give it a try”. Sure enough, despite being rated at 65w, and the MacBook Pro claiming it needed 85w, the MacBook Pro charged fine. I occasionally felt the MacBook’s power supply to see if it was going to over heat or anything, but it remained as cool/warm as it ever did when charging the original white MacBook.


I had found posts about going the opposite way (using an 85w to charge a 65w MacBook) and those posts seem to indicate it works – there is some auto-sensing thing-a-ma-jig in the MagSafe connector that allegedly scales back the juice (NOTE – I have not tried this).

For the record, I first changed the energy settings to “Better Battery Life” from “Higher Performance”, logged the MacBook Pro out, and I turned the screen brightness down quite a bit. However, it charged fairly quickly, so I’m not even sure that was necessary. I went to bed with the MacBook Pro charged to about 88%, and left it plugged in overnight, and woke with a 100% charge and no house fires to report. According to iStat, my MacBook Pro’s batery still has 100% health, so as far as I can tell, this did no damage to the MacBook Pro.

So in conclusion, yes, it works – although I am still keeping an extra MacBook Pro power supply on my Christmas list to leave at the lab.

17 Responses to “Can you use the 65w MacBook Power Adapter with an 85w MacBook Pro?”
  1. Jeremy Jones says:

    They do work fine. The one issue is if your laptop gets extremely low on battery. The 65w doesn’t have the fire power to start the charge cycle on a drained MBP battery. As long as you don’t run the battery down it will be fine. I actually use a 65w all day at work. I use a 85w at home.

    I have personal experience with the drained battery and the 65w not working. I have to run around the office finding someone with a 85w.

  2. Rich says:

    Incase anyone is interested (disclaimer – this is the opinion of an engineering student).
    60W or 85W refers to the amount of power which the power supply can deliver. For example a macbook pro will run off either, mine is using say 20W at the moment as I’m not up to much, but if you were doing some hardcore video transcoding and playing a GPU intensive game it could require 85W. If you tried to use 85W with the 60W supply I assume it would also use power from the battery.
    If your battery really needs charging and you try to do intensive things however, not sure what it would do.

  3. Erik says:

    Yeah, I’ve been doing this since August and have run into zero problems. I use the two cables interchangeably between my 15″ and 17″. I have never noticed any difference in performance, probably because it is usually near a full charge.

  4. Zorin says:

    I have a regular MBP power adapter and a MB adapter, which I purchased back when my MBP adapter died and right at that moment it was impossible to find MBP adapters.

    Both work fine; the only difference I notice is the MBP adapter charges the battery faster when it’s really low than the MB adapter.

    Because of this, I carry the MB adapter in my bag usually (it is lighter and smaller) and leave the MBP adapter at my desk.

    I have been doing this for over a year without issues.

  5. Works fine for me, could have told you that 😉 Been doing it for ages.

    Only difference is that the 65W charger will charge your Macbook Pro more slowly and if you’re using your MBP at full tilt will stop charging and just run the machine.

    There’s no auto-charge thing in the chargers; Here in Europe, a wall socket supplies 13Amps. Doesn’t mean you can’t plug a little lightbulb in instead.

    Volts are what will damage your computer; The Wattage of a power supply only refers to the amount of power an item can supply, not the amount it supplies all the time.

  6. Chad Landman says:

    I mistakenly used my wife’s white MB charger with my Early 2008 MBP for like 4 months without knowing it…but the only thing I noticed was that it charged more slowly, obviously. Other than that, it worked fine!

  7. Gabe says:

    My wife has an MB with the 65W and I have an MBP with the 85. They do work interchangeably, but I noticed several problems over the course of time.

    1) If the battery drains all the way, the 65W will work to powercycle the battery and start charging it, but you won’t have enough juice to turn the MBP back on for another 15 minutes or so.

    2) My wife was using my 85W on her MB and ended up burning out her battery. I couldn’t figure out why this happened and then was having the issues with my computer taking a while to turn on after a drained battery. I didn’t realize the two chargers ran different Wattage, and it finally dawned on me to check the wattage. We have now marked the cords and only use the ones that go with our computers. While my MBP should be able to use her MB, I don’t believe it is good for the battery long term. Since Mac battery life is one of their weaker points, I choose to stick with the chargers they were designed to work with.

    Hope that experience helps.

  8. Emil says:

    Indeed; the chargers from the MacBook Air, MacBook and the MacBook Pro are completely interchangeable.

    However an MBP that is completely discharged will need the 85w adapter to kick in the charging.

    The MacBook Air charger is my preferred choice for commuting – that’s the one i would get if needed a spare.

  9. foz says:

    I also used the 65w with the 2007 17″ MBP for a while, since my wife had a newer 15″ and we always swapped adaptors. One day I left it charging on the couch. My 2-year-old daughter sat down on the power supply and it was so hot it burned her and made her cry (no damage done though). It was *super* hot. I now make sure to use the proper adaptor with the correct laptop. I don’t know if there is a fire risk, but that 65w gets really really hot under load.

  10. Jeff Krieger says:

    I have found this interesting tidbit. I can charge off my wife’s Macbook cord. But if my MBP dies, it will not start up again off my wife’s charge (at least right away). I have to plug it into mine to get it going again.

  11. lloyd says:

    I can confirm that my MacBook Pro 85w power supply works with my MacBook. Don’t know if it effects battery as the battery on MB was dead before I tested it.

  12. miss lake says:

    To add to the useful comments above, if your MBP battery is completely flat a MB power adapter WILL start it but you need to leaving it charging for about 20 minutes first to give it enough oompf.

    Just saved myself a 90 min round trip 🙂

  13. Celene says:

    You know, I’ve been using my white macbook (Oct 2006) adapter with my newer Macbook Pro G4 for about three months, and the cord melted at the magnet! I don’t know what to attribute this to, but thought I’d mention it here.

  14. Jesse Badger says:

    Just to let you guys know from experience working at an Apple Store. We charge all of the macbooks and macbook pros with a 85W adapter. If you actually read the packaging for the 85W it clearly states that it works with both the Macbook Pro and the Macbook.

  15. Hans says:

    Most adapters are underdimensioned…. meaning they are overloaded with the task, ehnce the heaet. Would be best to build your own charger if you have the skill, heat dissipation can be better regulated than the closed boxes of the macs.

  16. Otaku says:

    I asked someone at the genius bar last night, and they said that the 65W adapter would shorten the battery life of the MacBook Pro. The 85W on the MacBook is also bad according to this person, but not as bad.

    I am not making any comment on the accuracy of these statements; this is merely what I was told.

  17. Guilherme says:

    Well, I am commenting from the future, but never mind…

    It’s 2016 now, and I recently got this Macbook Pro 15″, 2,4Ghz from 2010. The battery was stuffed up, making the trackpad pop up from its case, and the bottom plate round. The friend who gave me didnt have the power adapter. So I thought to give it a try on the 65w from my white. It didnt come alive. Megsafe light went green straight, but no power turned the computer on. So, I took it to Apple and genius took of the battery and plug a power adapter, it did turned on. Came back home thinking that maybe it was the battery and not the power adapter, tryed to connect it again with no sucess. So, 65w in this case didnt work in this computer without battery. I am getting a 85w next week and lets see what happens. Searching for a good battery for it as well…
    Greetings from the future!

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