Yes if you were at 40% the voltage would be much lower and I would recommend running the generator early to let the solar do the long absorption work later in the day.
In these conditions Magnum should run the voltage to 14.4+
if i was at 40% I would be Down 402ampHrs
an awful lot to return
6~8 hours of generator with PD70 and NO A/C, before solar could be used for absorption
Not gonna happen in this weather
maybe in Mid-winter
but i prefer to keep my bank above 70% if possible
I can't let it charge on shore power for a week in the driveway