When camping for an extended time without an electrical
hookup, I track amp-hours out.
Then at some point, I connect the Honda generator
and run it long enough to get back to 70-80% full amp-hour capacity. About that time, most chargers are starting to ramp down the current anyhow. I get the most charge for the minimum generator
I like amp-hours because it's a (relatively) simple value for the meter to track and judging the charge state by voltage is tricky because of the wait time to get a stable voltage after any charge or drain load.
Now, if I were to completely surrender to the dark force, I'd spring for the optional battery
temperature sensor since battery
charge is temperature sensitive. Haven't been able to justify it. Yet.