UsbchargeHandy Instructable from murph38_99 – “Create a USB car charger for any iPod or other Device that Charges Via USB by splicing together a car adapter that outputs 5v and USB Female plug. The most important part of this project is to make sure that the output your chosen car adapter is between 4.75v and 5.25v otherwise you risk damaging your device. Please verify voltage with a voltmeter.” Link.