Making my own car charger

[Schooleydoo]

ive got a passive Brodit, and a extusb splitter and want to wire in a charger. Can i use my sync cable, chop the usb plug and wire it into the 12v from my radio? Asuuming not to be honest, it must need a transformer to step it down to 5v? Anyone know where i can find a pinout diagram of the sync cable supplied with the Kaiser?

[mattdehat]

buy a car invertor from aldi £14 they come with 240v step down and usb..sorted .no chopping or soldering needed.also runs your laptop ect...