I believe that's not an issue in my case. If I understand it right, if I have my solar inverter in off-grid mode and it decides it needs generator power (i.e. because my batteries' strength of charge SOC reaches a set point like 20%), then when my inverter fires up the generator it tells the generator to run at full capacity until my battery SOC is up to a set level (i.e. 30%) and tells it to shut off. So if I have 60 kWh of storage, 10% of that is 6 kWh. That's about 40 minutes of run from a 10kW generator. Maybe 60 minutes to account for my home at night consuming a little power. We're talking less than a gallon of ethanol free gasoline (to keep it from gumming up the carburetor of the generator if it sits there for a while) per month.
Based on the output I've received from my solar system so far, I believe I could double the system and need about 45 minutes to an hour once per month from my generator, to supplement my solar to power my all-electric (once I replace the gas appliances) two story home as well as throw in 15 kWh daily into an EV (that I plan to buy next year whether or not the power company forces me to go off grid). The reason I want two 10kW generators if I go off grid is because I every now and then have family in for vacation (consuming more power than just my wife and me) and because I'd like a 2nd generator as a backup in case one quits.
But that's only if the power company forces me into either going off grid or paying their ridiculous monthly solar fee (that I'm so far avoiding). For now I'm happy with it as it is.
You should do a little more research on how this all works together. Unfortunately people who sell generators often try to upsell larger capacity units because they charge so much more for them. It is often said that for an off the grid system that you should buy a generator that is twice as large as the inverter in your solar system. The reasoning behind this is murky at best. In reality your generator should be just large enough to handle the maximum load that you will be putting on it plus a little fudge factor to handle equipment with large starting loads.
Here are a few figures from our past experience to think about.
Even on natural gas that still costs us just over $1 per therm, the generator still costs around three times what the power company charges for electricity... currently $.10 per kwh. Because our generator runs more efficiently on natural gas than gasoline 1 therm for us is the equivalent of a gallon of gasoline. Gasoline is now up to approximately $4 a gallon here in Washington. So you can see that electricity generated by our generator using gasoline would cost us around $1.20 per kwh to generate. This is based on our usage patterns with a 5kw generator and an average 2500 watt load.
Just wondering, have you added as much insulation to your attic and any other spaces that add heat gain during the day.
I am in NH. SO, I am more concerned about heating in the winter than cooling in the summer.
I am also living in a 1972 house. I added a foot of bonded cellulose insulation to my attic. I caulked around all windows and exterior doors. I even took off all of the electrical outlet plates on exterior walls and foamed/caulked around those. I replaced 3 of the 5 exterior doors entirely. The two remaining doors, I replaced the weather stripping. lastly, we added insulating curtains to the sliding glass doors and all bedroom windows.
The other major purchase was a wood pellet insert I installed when Obama let oil get up to $150/barrel. My furnace burns heating oil.
The biggest bang for the buck was the attic insulation. All the remaining items contributed small amounts but cumulatively they reduced my energy consumption.
Obviously, your goal would be to reduce heat gain in the summer months. However, insulation works both ways, heat loss and gain.
I have noticed since I did all of the above that my pellet usage is now down from the first winter. It does not take as much energy to keep my house warm.