Charging laptop from 12-volt battery

inverter. Doesn't need to be a pure sine wave inverter, a cheap modified sine wave inverter will do fine, as long as it has the wattage to do the job. Your MacBook Pro uses a switched power supply, not a transformer power supply, and if you look on it, assuming the sticker is still there, it says 110-240 volt, 50-60 Hz.

I paid $40 for a 400 watt MSW inverter a few years ago, and it works just fine charging my early 2008 MacBook Pro.