The MacBook's MagSafe power adapter is probably its best and worst feature. It works really well when you accidentally trip over it, but the patented adapter is being withheld from third-parties. This means that the adapter wasn't available for airplanes and autos for the longest time. Apple eventually address the former 7 months later when they released the US$59 MagSafe Airline Power Adapter (PN MA598Z/A, now an international part) that works with the in-seat DC power ports found on many commercial airliners.
Unfortunately, Apple still hasn't released a solution to charger a MacBook in an automobile, some 581 days (19+ months) later. Luckily a solution exists, with no help from Cupertino, thank you.
Mikegyver Computer and Tech., Inc. (MCT) has developed the first and only Magsafe automobile charging solution available for MacBooks. The MCT solution allows you to charge your MacBook or MacBook Pro on an airplane, in an automobile, boat and house–without wasting energy using inverters.
MCT does does their magic by cutting the tail off a genuine Apple power adapter and attaching a DC connector that works with the “N2” tip accessory that comes with the Kensington 120w Notebook AC/DC Power Adapter (US$140).
the Kensington 120w Notebook AC/DC Power Adapter uses patented technology to deliver all the power you need in a size that is 40% smaller and lighter than other power supplies. With its AC and DC power options, you always have the right adapter--whether in the office, on the road, or in the air. The Kensington Notebook AC/DC 120w Power Adapter is the ideal replacement for your existing power supply. It is designed to provide reliable power for today's larger, high-performance notebooks as well as other small mobile electronics such as iPods, cell phones, DVD players, and PDAs.
iGo’s juice70 (US$120)—which let you use a single power adapter with several devices; charge multiple devices simultaneously; and work with AC wall outlets, car accessory jacks, and airline-seat (EmPower) DC power ports–also can be used with the MCT solution.
MCT offers a complete package, including the Kensington 120w Notebook adapter and the modified Apple Magsafe adapter for US$210 (normally $230). The kit includes the Kensington 120w adapter (US$140), a modified Apple MagSafe Power Adapter (US$80) and a 90-day warranty. The Kensington adapter is covered by a one year warranty from the manufacturer. If you already have the Kensington or iGo adapter, MCT offers a complete MacBook adapter with a standard DC plug for US$120 and a MagSafe cable only for US$110.
Most questions about the MacBook car adapter conversion are answered in the MCT Q&A.