I use a multitude of devices in my Toyota Troopy GPS, PDA with GPS and OZi Maps, Phone and now a Vid Camera "Troopy Cam" a Motor Bike helmet cam and have set it up with a 32GB micro SD and can record at 720P for 13hrs good for a days drive in country Australia. So I use at this moment 4 sources of 12V, I also have a dual Battery system that I also connect a further 3 Deep cycle batteries to so if you would like to know to right way to do these things let me know. That is running 3 Way Fridges and or compressor type like the Engels and Waeco types.