House Battery Charge Question

Awesome info thanks guy. I woke up to 12.24 and the solar power charging it up again, but I am surprised that I would reach 50% batt on only one night of boondocking. Is this normal? I am in a 20’ born free van that has basically no amenities lol. The only thing I ran last night was tv for a couple hours, Xmas lights for a couple hours and then my Engle fridge which is always running on dc but supposed to draw very minimal power. I am also having trouble understaning how the inverter/charger comes into play? I have a freedom 10 model inverter/charger. My understanding was to turn it off if I’m getting low on batteries? Am I wrong and this thing somehow actually charges them while giving me power? My understanding was the only way to get charge is from shore power, solar or running the truck.? Sorry if it’s a noob question but I am new to having an rv and learning as I go. Crossing into Baja tomorrow. Happy New Years guys!