But if I convert my two natural gas appliances to electric, I'm getting rid of my natural gas bill. Along with it goes the $11 or so monthly fee I pay just to stay connected, not even counting how much I pay above that for per cubic foot usage. So that's part of the math.
But this is only if my power company forces me to pay the "solar fee" of about $54 per month on top of the $15.86 per month we have to pay just to stay connected to the power company (before paying more per kWh usage). If I never have to pay that, then I'm happy not buying generators anyway. The power company is my "backup" whenever my batter backup isn't enough. But if I have to pay that fee and cut off my connection to the power grid, I'll gladly buy about 1 or 1.5 gallons of gas per month to feed a 10kW generator (maybe a 2nd 10kW generator as a backup to that or if I have company over while it's raining) over having to pay $11/month to the natural gas company on top of the cubic foot usage when I rarely use my generator -- after buying a really expensive natural gas generator.
Keep in mind that if my inverter was to kick in the generator when my SOC gets to 30%, I still have 10% my inverter pulls from the batteries (before it has a 20% SOC cutoff to not pull from the batteries at all), which is currently 3 kWh (it'll be 6 kWh if I double it to go off-grid). So that's 6 kWh my inverter can pull the batteries from while it's getting 10 kW from a generator, before it gets another 10 kW from the other generator if it needs it.
I’ll gladly buy about 1 or 1.5 gallons of gas per month to feed a 10kW generator
You should find the fuel usage chart of the generator that you are considering. Even if your system does allow higher amperage charging which will reduce the life of your batteries, your system will take much more than an hour to charge batteries from 20%. It will also take much more than a 1 to 1.5 gallons of gas if it is somehow running near its capacity.
Natural gas is much easier on a small engine than gasoline. We have been using the same 5kw for over 25 years with nothing but a yearly oil change and a new spark plug. It still starts like a champ.