HT201700: Find the right power adapter and cord for your Mac notebook

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Aldebaran Borealis

Q: Higher Voltage versus Higher Wattage?

This article points out correctly that I can use a power adapter rated at a higher wattage with my computer without damaging either the adapter or the computer.  However, the 15" MacBook Pro has a significantly higher output voltage than the adapter rated for the 11" MacBook Air.  The Air is rated for 14.5 Volts but the MBP is rated at 18.5 Volts.  Will this damage the Air?

Posted on Jun 4, 2012 1:50 PM

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Q: Higher Voltage versus Higher Wattage?

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  • by SP Forsythe,

    SP Forsythe SP Forsythe Jun 4, 2012 3:10 PM in response to Aldebaran Borealis
    Level 5 (5,399 points)
    Jun 4, 2012 3:10 PM in response to Aldebaran Borealis

    A) Apple has indicated that all three adapters are perfectly suitable for the MBA. You can use one of the MagSafe adapters that is larger than yours, just not smaller. Hence the Air is more or less going to be universally OK with all the adapters.

     

    B) I use my 85 watt adapter on my Air approximately 95% of the time, and the 45 watt adapter maybe 5% of the time with absolutely no problem. The reason is that I want to have only one adapter on my desk, and not worry about anything. The 45 watt is packed away in my MBA travel bag.

  • by captfred,

    captfred captfred Jun 4, 2012 3:10 PM in response to Aldebaran Borealis
    Level 7 (26,329 points)
    iTunes
    Jun 4, 2012 3:10 PM in response to Aldebaran Borealis

    I won't damage the MBair. 

  • by JasonFear,

    JasonFear JasonFear Jun 4, 2012 3:15 PM in response to Aldebaran Borealis
    Level 5 (4,940 points)
    Jun 4, 2012 3:15 PM in response to Aldebaran Borealis

    Hello Aldebaran,

     

    I used the charger for a 15" MBP on an 11" MBA in a pinch for a week long in the field seminar when my 11" MBA power brick failed. There was no damage/harm to the machine during that week of use. The bigger issues that occur is when you role reverse (trying to charge a 15" with an 11" charger). More often then not, especially if the machine is under load the power adapter can't move enough to juice to power the machine and it'll begin to drain the battery.