/diy/ - Do It Yourself

Hey /diy/. I am thinking of converting a van into a camper van just in case I ever end up without a home. How many 12 V batteries would it take for an electrical system that would give me enough electricity to charge a netbook battery, operate a small lamp, and charge a phone for a 2 to 3 week period without recharging the batteries? I am new to this stuff. My ultimate goal is to get some wiring in a van with some power outlets...I am currently doing some reading about basic electronics stuff.