Inverter FAQ's also includes a "How long can I run the inverter on my battery?" worksheet about halfway down the page. The
watts estimates are very helpful as well. Its a quickie way of figuring out how big your battery bank needs to be or a rough estimate of how long the battery bank you're stuck with will last. Just remember, you will rarely be running everything at one time. And refrigerators/freezers will easily stay cold for the 8 to 10 hours if you keep the doors closed and run them for at least 2 hours every 8 to 10 hours (we like to run a couple hours before bed and a couple hours when we get up before hitting the road). I can't see running the generator overnight if things like lights & water pump are on batteries for midnight runs to the loo.
For example we could watch TV for almost 5 hours off the (3 12 volt) battery bank while sitting in a parking lot with no generator running. Would we? Probably not. But nice to know that we could. As it is, I am probably quite safe pulling into a parking lot, run a generator while I cook supper, watch a movie on TV, run the water heater for showers, check out our options for the next stop and the weather (always check the weather) on the desktop computer, run the freezer & refrigerator for a few hours, charge the cell phones if needed, then shut down for the night. David could even watch the TV if he wanted to (more likely only if we were stuck in a parking lot for a day or two due to bad weather). Do I care if we "disturb" others in a parking lot with a generator? Nope. The semi truck that seems to park next to us with the engine running all night tends to be pretty loud. The semi trucks that park in the empty lot across the 4 lane street from us with their engines running all night are pretty loud.