[wingnut60]

If you want to charge batts faster than the gen alone, use an auto battery charger at the same time. The converter is somewhat limited in what it will do (I assume you are using the Onan onboard gen) so you can get a quicker charge using an auto charger at same time--won't hurt anything if the auto charger is multistage.
I used a couple of 12volt sealed batteries placed in the basement and paralleled to the main batts for a couple of years to give me more run time--worked pretty well.
Be sure the batts are in top shape before you get there.
Lived in Alb 2 years and never went to the fest...