60W Magsafe showing as 85W

Discussion in 'MacBook Pro' started by AeroZ, Jan 28, 2015.

  1. AeroZ, Jan 28, 2015
    Last edited: Jan 28, 2015

    AeroZ macrumors 6502

    AeroZ

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    #1
  2. catzilla macrumors 6502

    catzilla

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    #2
  3. AeroZ thread starter macrumors 6502

    AeroZ

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    #3
    Yes, I read that article too.
    Tho the question is, is it OK if the system shows 60W charger as 85W or it might cause some serious problems?
     
  4. damidget macrumors regular

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    #4
    It should be fine seeing as its rated from 45W-85W.
    Just be careful with it
     
  5. Gjwilly macrumors 68030

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    SF Bay Area
    #5
    I'm in the same boat but sailing the other direction.
    My 85w charger is now showing up as 60w.
    We should have swapped cables.
    ;)
    I'm thinking that I'm a little better off though because if the chip in the Magsafe tells the MacBook what charger you're using then your charger is always going to be overtaxed.
    The MacBook is going to be trying to draw 85w out of a charger designed for only 60w.
    That's going to lead to excessive heat at the very least.
     
  6. joe-h2o macrumors 6502a

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    #6
    No it won't. It will draw 60W as before. The MBP will draw the power it is designed to from the charger (if able), so a 13" MBP will draw around 60W at full load.

    From Apple's own pages: http://support.apple.com/en-us/HT2346

     
  7. priitv8 macrumors 68020

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    #7
    But it won't work the other way around - i.e. 15" MacBook Pro won't attempt to draw 85W out of a 60W (or 45W) charger.
    Otherwise the charger brick would catch fire.
     
  8. steve23094 macrumors 68000

    steve23094

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    Apr 23, 2013
    #8
    You should try to source this information direct from Apple just to be sure, it's probably on their website somewhere. Because a normal device would draw the additional power and this could result in a potentially dangerous situation.
     
  9. priitv8 macrumors 68020

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    #9
    I have run my 15" MBP off of a 65W charger. No fire. Just charges slower.
     
  10. TheIguana macrumors 6502a

    TheIguana

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    #10
    Keep in mind that your computer will make up the additional power required from the battery if you exceed the amount of power that the adapter can supply.

    But yes that is right... except in this case they are talking about repairing a broken adapter by grafting a new MagSafe cable on to it.

    Specifically, in this case they are talking about grafting a MagSafe cable from an 85W charger onto a 65W charger (by accident). Since the cable contains the circuitry telling the Mac what wattage adapter is connected it could cause problems. For instance if this adapter were plugged into a 15" MBP that needs 85 Watts and tries to pull that from the charger it could overload it - unless Apple has built in further redundancy into these chargers.
     
  11. AeroZ thread starter macrumors 6502

    AeroZ

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