11 Replies Latest reply: Dec 6, 2013 12:14 PM by PlotinusVeritas
John Reed6 Level 1 (5 points)

A friend wants to power her MacBook Air on her boat from a 12V source (DC) What should she do, to get the most power-efficient solution?

MacBook Pro, Mac OS X (10.7.4), MacBook Air
  • SP Forsythe Level 5 (5,380 points)

    Use a 12V inverter, with the necessary wattage output. It would be a bad idea to at least get a 100 watt inverter, that converts 12V DC "cigarette lighter" plug to 110 V AC. You can get one at any consumer electronics store.

  • John Reed6 Level 1 (5 points)

    I failed to mention that my friend has a very limited amount of available energy. She uses a solar array for power, which has a peak output of 100 watts. I'm afraid the combined inefficiencies of the inverter + the MacBook Air power adapter would yield less than 45 watts for charging the computer. It would seem like there should be a way of powerring directly from the 12V source, since the MBA takes 12V at its MagSafe terminals, I understand?

  • carl wolf Level 6 (14,625 points)

    Check the Apple store.  There are power adapters that plug into a cigarette lighter.  Although you're not interested in the cigarette lighter connector, a car battery provides 12VDC, and you can cut off the cigarette lighter connector, and connect it directly to a 12VDC power source.

  • John Reed6 Level 1 (5 points)

    The Apple Store carries a MagSafe Airline Adapter, but it's different than a car lighter socket configuration. The lead Genius recommended against any other forms of power besides what comes with, or the airline adapter. But I'd be inclined to try your suggestion (carefully!).

  • John Reed6 Level 1 (5 points)

    By the way, I checked the MagSafe pinout configuration on Wikipedia. According to the reference, there are two instances each of 16.5V, and Ground. If true, this would sort of put the 12V system beyond a reasonable tolerance from the "required" 16.5V? It would be interesting to know how much tolerance the Air could stand on this voltage, and still charge and operate normally, without damage. Any clues, anyone?

  • RRFS Level 5 (4,490 points)

    Looking at the system information power panel my MBA shows 8.322 volts on the battery. 12 volts would adequately charge the battery because the charging regulator is inside the MBA not the Adapter. I'm not sure how the DC is switched between the 4 connections as it is reversible as to how it connects with the MBA at its power port.

  • DOlec Level 1 (0 points)

    Please. Please Apple explain to me why in your closed universe you justify the reasoning to not be compatible with simple, standard 12v adapters? I invest in 12v solar - not 15v obscurity. Individual energy production is the next Internet and we need simple solutions to adapt to energy options. I understand being a closed system and building proprietary systems but independent energy production is a fast evolving animal and Apple needs to see and embrace this trend. Open up your adapters and embrace 12v solutions. Trust me.


    Embrace battery innovation and independent power generation and build user experiences to empower it. Your smart enough. 

  • RRFS Level 5 (4,490 points)

    This Forum is NOT Apple. We are Apple product Users like yourself, we are not a part of Apple. We post to this Forum trying to help others gain knowledge or solve problems, that's all. Have a complaint for Apple? Post here:


  • Dankichi Miller Level 1 (0 points)

    Hey so John, all you need is a Dc-Dc converter. with 100 watts at 12 volts, you can step up to 16.5, with anything from 45- to a ways. It would need a magsafe 2 or magsafe 1 with an adapter, and would need a little soldering, but it's pretty easy. I could do it. My dad, (65) could do it. So all you need is the DC to step up, then you're good to go.

  • timelord51 Level 1 (0 points)

    There is a 3rd party12 Volt adapter for the macbook--





  • PlotinusVeritas Level 6 (14,725 points)

    Embrace battery innovation and independent power generation



    I know 2 people that charge their Air off a roll up solar cells with a cigarette female adapter (MOST solar cells come with them)


    using that an a 12V cig. adapter



    So, its very easy to do