Macbook Air/Pro Power Cable Compatibility?

Discussion in 'MacBook Pro' started by m021478, Jun 26, 2011.

  1. m021478 macrumors 6502

    Joined:
    Nov 23, 2007
    #1
    My wife has a Macbook Air and I use a Macbook Pro. Our power cables for our respective computers are plugged into the same power strip under a desk, and the magnetic part of the power plugs is visible coming out of a hole in the top of the desk but the problem is that both plugs look identical and both plugs fit each of our computers.

    I wanted to know if it's "OK" to use her Macbook Air power cable (45W) to charge my Macbook Pro, and if it's "OK" to use my Macbook Pro power cable (85W) to charge her Macbook Air?

    When I say "OK" my main concern is that there is no inherent fire danger by swapping the power cables. I assume of course that the 45W power cable that came with her Macbook air would charge my Macbook Pro much more slowly than the 85W cable, but will the 45W power cable charge the Macbook Pro if I leave it connected overnight?

    MY MOST IMPORTANT PART OF THIS QUESTIONS IS - is there any fire danger by freely using each others cables?

    Any advice would be greatly appreciated... Thanks!
     
  2. alust2013 macrumors 601

    alust2013

    Joined:
    Feb 6, 2010
    Location:
    On the fence
    #2
    Fire danger, no. Although the 45W charger will have a heck of a time charging the pro, especially if you are using it at the same time. It would charge if you left it overnight though. The 85W charger would act the same as the standard charger for the air. My suggestion would be to take a sharpie and make some sort of mark on one of them so that you can identify it and you don't have to worry about taking too long to charge.
     
  3. Virgo macrumors 6502

    Virgo

    Joined:
    Jun 7, 2011
    Location:
    Los Angeles, CA
    #3
    Just put a little piece of colored tape on one or both (if different colors) of the ends of the plugs. Problem solved, and you don't need to find out the hard way if something could go wrong.
     
  4. lindstedt56 macrumors regular

    Joined:
    Jun 19, 2011
    #4
    Nothing bad will happen it would just take longer to charge
     
  5. ReddDraggon macrumors member

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    Jun 14, 2011
    Location:
    North Wales or Manchester
    #5
    Put some insulation tape on one (or different colours on both) to identify it(/them).
     
  6. WardC macrumors 68030

    WardC

    Joined:
    Oct 17, 2007
    Location:
    Fort Worth, TX
    #6
    You know those adhesive colored Dots they sell at office supply stores, like to marking file folders? I have used those to mark PowerBook 100 series chargers (like the PB 100, 170, 165c, and 180c chargers) which were different voltages and some had different size connectors. They come in Red, Yellow, Green, Blue. A pack should cost you no more than $3 or so. Just put a different colored sticker on the end of the cable near the connector. It will work and you won't have to permanently mark your cable with a Sharpie.
     
  7. fat jez macrumors 68000

    fat jez

    Joined:
    Jun 24, 2010
    Location:
    Glasgow, UK
    #7
    Basically, if your MBP needed more than 45W, it would start drawing power from the battery, so eventually it would shut itself down due to insufficient power. The MBA will be fine running from the 85W charger though.

    I'd go with the other suggestions and mark which charger is which. Or if you're feeling flush, buy a second 85W charger and then it won't matter which one you plug in ;)
     
  8. Naimfan macrumors 68040

    Naimfan

    Joined:
    Jan 15, 2003
    #8
    No.

    The 45 watt Air adapter will take longer to charge your Pro, but there is zero fire danger (unless, of course, the adapter is damaged). And if you are using the MBP intensively, as others noted, it may not supply sufficient power to both operate the MBP and to charge the battery.
     
  9. jace88 macrumors regular

    jace88

    Joined:
    Jan 3, 2011
    Location:
    Sydney, Australia
    #9
    Thanks for a great thread but just to confirm, if I have a Macbook Air 2010 or 2011 (sorry for thread hijack but still kindof on topic!), which as far as I know, uses the least power out of the Macbook range, will that mean I can use any of the higher power/wattage chargers such as the normal Macbook Pro plugs and it'll work? Any limitations which won't work/automatically adjust?

    Any potential issues with using an older Macbook (say the 2007/08 white ones before unibody generation) charger on the new Macbook Air as long as the plug fits?

    ----------

    Found this through Google: http://support.apple.com/kb/ht2346

    ... but I'm not 100% sure whether I can use an old style Macbook charger with a new Macbook Air. This quote implies yes:

    On another note, I wonder what the significance of the original MBA vs. the 2010 onwards MBA plugs are.

     
  10. fat jez macrumors 68000

    fat jez

    Joined:
    Jun 24, 2010
    Location:
    Glasgow, UK
    #10
    The plug shape was a change to be more aesthetically pleasing. Yes, you can use higher rated chargers on a MBA, that's just the peak power the charger can supply. The Air will only draw as much as it needs.
     
  11. jace88 macrumors regular

    jace88

    Joined:
    Jan 3, 2011
    Location:
    Sydney, Australia
    #11
    Wow thanks for that. I'm impressed that Apple maintains backwards and forwards compatibility with chargers! Also convenient that MBA is the lightest in drawing power which means it'll work with all the others.

    I wonder why they don't recommend using the 1st gen MBA cord though :S Presume it was customised to suit the MBA of that era.
     
  12. fat jez macrumors 68000

    fat jez

    Joined:
    Jun 24, 2010
    Location:
    Glasgow, UK
    #12
    I guess there is always the possibility of the shape of the socket changing so it won't fit an older charger. I've used both shaped chargers with a 2009, 2010 and 2011 MBP and it's been fine. I've even used the 65W charger that came with my work's 2011 13" MBP with my own 2011 15" MBP. It still charges, providing I don't do anything that loads up the CPU and/or GPU (mind you, Starcraft 2 will drain the battery on my 15" MBP, even when it is plugged in to its own charger, as the power load from the CPU and GPU while gaming is greater than the 85W that the charger can supply).
     
  13. jace88 macrumors regular

    jace88

    Joined:
    Jan 3, 2011
    Location:
    Sydney, Australia
    #13
    That's crazy- never even though that was possible on a laptop but now that you mention it, it makes sense.
     

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