I'm an early riser, I usually take my voltage reading first thing in the morning, before I switch anything ON and before my tiny
solar panels have put any charge voltage on the
battery. If I can get the
battery charge status within about 10% that's more than good enough for my purposes. My camper is 100% LED and we use the
lights conservatively, the big power hog is the
furnace, we can camp multiple days on a single Gr27
battery. If it gets too low, I can still back up the truck, plug the pigtail and let it idle half an hour or more.