I was running a small compressor that was drawing 6 amps and could get 6 hours off of it with a deep cycle battery, It would be down to 10vdc when I shut it off. have you checked into the LED type lights? very low usage and very bright with long life. I was looking at one of my camp lights that holds 6 D size batteries that has a small florescent bulb and a fan than runs about 3 hours longer if you run the fan on low
