While this is a slightly different topic, I'd observe that with 8 house batteries we have a theortetical 880 AH. Conventional wisdom is that you want to avoid going below 1/2 of that if possible to prolong battery life. While I've not yet been able to fully determine the phantom load w/inverter off, it's likely less than 5. With the inverter on, and everything else off, it approaches 14 A. If you're using TV, etc, w/the associated electronics, it goes to around 30, and of course higher as you turn things on. We have a "Sun Runner" 2 x 100 W solar panels with a high end controller (unadvertised Alpine option), and that definitely helps. But the biggest "help" is turning the inverter off when AC isn't needed. At the Qz rally we ran the generator perhaps 1.5 hrs per day (average) to compensate primarily for the inverter/AC usage -- such as two NFL playoff games on Sunday. That kept the batteries reasonably topped off during the rally.
2007 34' FDDS Ltd SE