[twindman]

I used to run 1 A/C unit on a 15 amp circuit, but as it heated up the amperage went from around 13 steadily up to 16 or 17. When the unit has sat around a while, the converter will pump out 6-8 amps to charge batteries. Then for each light (12v) you turn on, the 120 circuit amps would increase 1.5-2.0 amps. So it doesn't take much to hit the 15 amp limit.
Edit: I now use a 30 amp circuit I installed. Much better!