The solar maintains the batteries way better than I could at home. Plus I don't have to find a place to store them nor lug 250 lbs of batteries from the camper to the house. I can also turn on lights if I need to because the power is there.
Looking at the log, the solar puts back about 7 Ah per day which equates to the 300 mA phantom load. At that rate if I got zero solar it would take a month to be down 50%. I generally check the trailer in storage every two weeks or so.
Looking at the log is interesting. I will see days that don't show much (1 or 2 Ah) solar charging due to overcast or clouds (or snow). The next time it's sunny, the solar cranks up and puts everything back. Or if the panels are snow covered when I arrive it's nice to see the amps jump up from zero to 10 or 15 as soon as I sweep them off.