Making Your MagSafe MacBook Road Trip Worthy

I have joined in with a chorus of geeks who wish they could use and recharge their MacBooks while they were in the car or boat. But Apple only makes a DC adapter that is compatible with airplane power ports and not with 12V car (cigarette lighter) ports. Since the MagSafe connector is patented, and they have yet to license it to third parties, there just aren’t any commercial solutions to-date. Sure you could use a power inverter to plug your normal power brick in to your car, but the conversion from DC to AC and then back to DC is extremely inefficient, and I’ve found most devices to be rather noisy and hot. I was looking for a DC-DC conversion solution, and I figured I would have to take matters into my own hands.

MagSafe Pinouts

I am a decent maker/hacker and I love playing with electricity. I can’t tell you how many times I’ve electrocuted myself in this lifetime… all in the name of science and discovery of course. Nevertheless, I am out of practice, and when I looked at the four or five pins at the end of of the MagSafe adapter, I assumed that there was some complexity to the voltage and polarity, and I had neither the time, nor the drive to figure it out. Plus, my MacBook Pro is now my primary business asset. If I mess it up by shorting it out somehow, this experiment gets very expensive very quickly. So, I put this project on the bottom of my to-do list as I waited for something better to come along.

About a week ago, I came across this link (via RubyHead) to Mike (MikeGyver) Lee’s website where he sells both turn-key solutions as well as instructions to build your own DC-DC power adapter for the MacBook and the MacBook Pro. The great thing is that I already owned one of the third party power adapters that he recommends, so all I needed was about $7.00 worth of radio shack parts. Awesome! So, I bought the do-it-yourself instructions from Mike Lee, and gave it a go last night. So far it works great!


It turns out that the polarity and the pinouts on the MagSafe Adapter are really no big deal. I won’t give away the details in this post. So if you are interested in doing it yourself, or even buying a turn-key solution, please check out Mike Lee‘s information. I advise you to visit this site sooner rather than later as Apple has away of making cool and helpful things like this disappear through cease and desist orders. Anyway, I now have a road-trip worthy MacBook Pro.

[UPDATE: 2007-06-25 10:30 AM PST]

Yes, this configuration does charge the MacBook’s battery, unlike the Apple Airline adapter which just powers the laptop. It’s hard to see, but the indicator light on the MagSafe plug in the picture above is indeed orange.