Hi Jonny,
Generators are expensive to run, and noisy.
No one in their right mind would try to recharge a battery bank to 100% using a generator. The best that can be done is 50% to 90%. Why? because once a battery is about 85% of fully charged the charging rate drops to 5% of the total capacity of the bank. For 200 amp hours that means one hour of charging them for possibly 7 more amp-hours into the bank. At 90% state of charge that drops to 2.5% of the total capacity of the bank.
How long does it take to fully recharge a battery bank? The answer is as much as 168 hours (1 week)
Parasitic loads account for 35 amp-hours per day.
After day 1, you only have 90 amp-hours to play with. Minus 35 amp-hours = 55 amp-hours.
To put that in perspective 55 amp hours is three 1156 2 amp bulbs for 9 hours.
Or you can run the furnace in my rv (which draws 9 amps) for six hours.
Of course, you can choose to go below 50% state of charge, and that works well for some folks.
