Magsafe 60watt vs 85watt

Discussion in 'MacBook Pro' started by rkriheli, Nov 2, 2006.

  1. rkriheli macrumors member

    rkriheli

    Joined:
    Dec 11, 2002
    Location:
    new york, ny
    #1
    Apple recommends using the 85watt with a Macbook Pro. I am considering purchasing a second one that I can leave at work without carring it around and I see some used 60watt macbook magsafes at good prices.

    Questions are:
    1 - Will it work?
    2 - If so, will it cause any problem?
    3 - Has anyone tried using a 60w magsafe with their macbook pro's? if so, can you let me know how it works out for you?

    Most appreciated!
     
  2. mdntcallr macrumors 65816

    mdntcallr

    Joined:
    Aug 1, 2000
    Location:
    Los Angeles, CA
    #2
    Do NOT use a lower power magsafe power adapter. it is for the Macbook. NOT Macbook pro.

    it will not work properly with your mac. if it works, it will not actually allow for charging your battery. also, it will not provide the full amount of battery power your laptop needs.

    a macbook doesnt have a full power graphics chip nor the needs of a MBP. on top of that it may actually harm your laptop
     
  3. jeremy.king macrumors 603

    jeremy.king

    Joined:
    Jul 23, 2002
    Location:
    Fuquay Varina, NC
    #3
    It DOES work and it works fine. I use my wifes MB power adapter with my MBP almost ALL THE TIME. It DOES charge my laptop and I have NOT experienced a single problem in the 5+ months that I have been doing this.
     
  4. rkriheli thread starter macrumors member

    rkriheli

    Joined:
    Dec 11, 2002
    Location:
    new york, ny
    #4
    wow - 2 different replies. i dont know what to think. anybody else with experience? i am leaning towards using one since it has worked fine for kingjr. anyone else?

    :confused: :confused: :confused:
     
  5. Apple2Mac macrumors regular

    Apple2Mac

    Joined:
    Sep 3, 2006
    #5
    I glad it works, but that makes me feal uneasy to risk my MBP....
     
  6. jeremy.king macrumors 603

    jeremy.king

    Joined:
    Jul 23, 2002
    Location:
    Fuquay Varina, NC
    #6
    The way I understand it, its fine to underpower a device but never ever ever try a power supply that exceeds your devices requirements. This is why I won't use my MBP adapter with my MB, although I believe I read that it auto switches down to the MB power requirements.
     
  7. NJuul macrumors 6502

    Joined:
    Mar 15, 2006
    Location:
    Boston
    #7
    I've read somewhere that they can be used interchangeably on both machines, but that it takes longer to charge an mbp with a 60 watt adapter.
    That said, I wouldn't want to risk my own unless I was absolutely certain.
     
  8. ipeleus macrumors newbie

    Joined:
    Dec 31, 2006
    #8
    Has anyone solved this mystery yet of the Macbook and Macbook pro Magsafe interchangability?

    Pretty inconvenient if you have two Magsafe adapters looking exactly the same in the same place.

    Any help appreciated
     
  9. Mobility151990 macrumors newbie

    Joined:
    Nov 26, 2006
    #9
    hi, i have had two macbook pros, the old 2.16 17" and now i have the new c2d 17" and i have used both with the 60W power adapters at times, basically using friends @ school etc. Works fine, takes a little longer 2 charge but i can still use it and charge the battery at the same time, no harm done!
     
  10. ipeleus macrumors newbie

    Joined:
    Dec 31, 2006
    #10
  11. cblackburn macrumors regular

    Joined:
    Jul 5, 2005
    Location:
    London, UK
    #11
    Switching PSU's like the ones provided to charge the MB/MPP's are designed to be like ideal voltage sources. i.e. whatever the load the supply will keep the same output voltage, hence the power supply will supply as much power as is needed by the device.

    The reason there are two types of adapter are that the more power is drawn the larger the heat dissapated in the PSU. The components in the 60W device will only be rated for dissapating 60W's worth of heat. If you pull 85W through it it will probably work for most of the time, however. There is a chance that it will overheat and kill itself.

    Most modern switching PSU's come with a feature called a "crossbar". This electronic device is designed to shutdown the power supply in the event of a malfunction. These are put in place because one of the most common failure modes for a switching PSU is to dump mains voltage DC on the output and trust me your MBP won't like 230V DC :-D.

    So in conclusion, using a 60W adapter once in a while is fine. Using one regularly is *probably* going to be ok. IF you're really paranoid only ever use an 85W.

    HTH

    Chris
     
  12. ipeleus macrumors newbie

    Joined:
    Dec 31, 2006
    #12
    thanx for your explanation Chris. really appreciated
     
  13. NYR99 macrumors 6502a

    Joined:
    Dec 30, 2007
    #13
    Wow, I really went deep into the archives to find this thread, but I want to know if anyone has anymore info on this.

    I just bought a MacBook Pro and I want to know if I can use my old MacBooks MagSafe to charge it while its at my desk. This way I can have one always plugged in at my desk, and one always in my case with my MBP.

    Thanks!
     
  14. Sankersizzle macrumors 6502a

    Sankersizzle

    Joined:
    Jun 5, 2010
    Location:
    Canadadada
    #14
    hey NYR, my girlfriend had a macbook but dumped water on it and it broke. so she got a macbook pro to replace it. long story short she's been using the macbook charger (not the new charger, never unpacked from the box... :p) for almost a year now and no problems to report (with the power supply area, anyways...).

    hope this helps!
     
  15. NYR99 macrumors 6502a

    Joined:
    Dec 30, 2007
    #15
    Thanks for the info. I don't think it'll do any bad either but I just want to be sure. Anyone think it its a bad idea?
     
  16. doktordoris macrumors 6502a

    doktordoris

    Joined:
    Mar 14, 2009
    #16
    I just checked and my 2009 model 2.53 15inch MBP, that I bought a week before the refresh (d'oh) came with a 60w PSU.
     
  17. KirkL macrumors 6502

    Joined:
    Jul 27, 2010
    Location:
    United States
    #17
    Ya exactly. It would be fine, but it would just take much longer to charge the MBP with a 60Watt (MB) Charger.
     
  18. NYR99 macrumors 6502a

    Joined:
    Dec 30, 2007
  19. KirkL macrumors 6502

    Joined:
    Jul 27, 2010
    Location:
    United States
    #19
    Good Luck!
     
  20. macagain macrumors regular

    Joined:
    Jan 1, 2002
    #20
    So, I was doing some research trying to figure this out a couple of weeks ago trying to figure what works on the plane... This is what I learnt:

    1. On the 2009 15" 2.53 w/o the 9600 (i.e. only on board 9400), the 60W charger works fine and charges as well. In fact they come with a 60W brick.

    2. On the ones with both dedicated and on-board video, if running the dedicated 9600, the 60 watter does work, but will only either charge or power, not both at once. (Combining both these points would lead me to conclude that if running on just the on-board 9400, it should do both... but I don't know the answer to this.)

    btw, lots of people do buy the 60W charger to use onboard international flights (on united first and biz, you don't need special adapters), as most aircraft power points are only rated for 75W. I do know of cases of the 85W brick blowing the circuit breakers on planes.
     

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