Good to know that some no-name stuff actually works.
You can easily avoid those odd few minutes of generator run, if this is only for microwave. Most common task is meals reheating, and you can use a stove for reheating liquid items like soup, and a double boiler aka Baine Marie for everything else. Top up the battery in the morning, and forget about that stinky contraption for the rest of the day. Though, with only one battery you might have to run a genny for another 30-50 minutes in the evening, to prevent the charge from dropping too much. One battery will be stressed a bit if you run 120V items daily.