Sam that's sorta the idea. The problem with an inverter is by the time I put in a second battery and inverter it will take up as much space as a small coil. What I was thinking was striping the coil from an old 5kva honda genset. Which would produce between 15-20 amps or 3300+ watts. An inverter to do that would drain a 100ah battery in no time and would cost a fortune. Plus this would give me true sine wave leccy so can happily run a microwave of it.