Until you figure out how many amps you use daily, by doing a power audit, you'll never know how much you need to put back in, if you ever plan on getting solar panels to do the recharging.
Do a search on how to do an electrical power audit here, since you've been here 11 years.
You sound set up on getting your batteries charged to 90% relatively efficiently, but getting in that last 10% is critical, and doing it by generator is generally a lot of generator noise and gas wasted for running a long period of time to get them there, better done on a pedestal with your monkey wards, not a portable generator.
Getting the last 10% charge back in, is, however, a good project for solar, even a small foldable portable solar panel set up, after an hour or two run first thing in the morning with the red machine to first get them to 90% SOC.
