I'm glad I don't have to worry or think to hard about blfs 20-50, 40-90, or other misc charge range #s.
The scenario I use is this. By the dinner time are the batteries at 60-65% SOC, if they are...great I'm watching tv, charging computer, phone, tablet and maybe pop some popcorn in the microwave and still leaving the inverter on, then by early morning when I wake up at 5am there will be aleast 30% SOC (70% DOD)to make my 12 cup coffee pot and use my microwave for 5 minutes. If not I hook up the generator up for an hour sometime during the day to drop a quick 100ah (20%) into the batteries. Just live life in a psoc at times till solar can finally fill the batteries.
But then the batteries are only 5 years old with daily 35-40% +/- depth of discharges totaling 1,600+ cycles so far.