I discovered early in our ownership that the steps were tied to the chassis battery and leaving the steps on drained the battery. No problem starting when battery dead with the battery boost and house battery.
Did two things (school of hard knocks): 1)turn off the steps when not being used for awhile and 2) installed a battery disconnect switch on the chassis battery. This was the simple bar switch screwed into the battery. No problems with dead chassis battery since.
I do run the coach at least once a month on the road during the winter to charge all the batteries and exercise things.