When you monitor the batteries use a multimeter to check the actual voltage of the batteries on the posts. Don't ever let them get below 12v
. The monitor panel batter level is not accurate and if there is a load on the system it will reflect a lower battery state. Using a 3 stage charger will help maintain the batteries better. For solar the other option is a portable solar panel. That way you can move it around to follow the sun or park in the shade and still charge without the generator. I doubt running a generator for a few hours would charge your batteries to 100% if the batteries were discharged heavily. Batteries will charge up fast to 80% then it takes longer to get the last 20% as the charger starts to reduce the amps to prevent damage to the batteries.
2008 Classic 25fb "Silver Mistress"
2015 Ram 2500 6.7L Cummins. Crew Cab, 4x4, Silver
2010 Tundra 5.7L, Double Cab, 2wd, White