Charging Amps engine alternator vs Generator

Pulled my batteries and found 3/26/2011 I wrote on the side. They have a 30 month warranty and I have had them 43 months. Boy time flies, seems like we just bought them. Did a hydrometer test and all except two were 1300 or above. The other two were 1285-1290. Did some adjusting with the Xantrex battery monitor and a multimeter. Seems that adjusting the amp capacity on the Battery monitor system down from 85 to 60 or170 to 120 amp total capacity gave me the correct percentage of charge. As the batteries charged up, the percentage of charge increase accordingly on both the Battery monitor and multimeter and a charge table( voltage equals % of charge). So the batteries have lost 30% of their capacity. Probably time to get new ones. Unfortunately, my small battery compartment and mounting precludes me from getting group 27 or 6 volt batteries.
For those of you commenting on using the microwave and generator for bagels, we were in a hurry to get on the road that morning. It was generator hours and it was actually bagels, Morningstar Breakfast patties and Jimmy Dean Breakfast croissants. I know you were all concerned that just bagels in the morning isn't enough to fill hunger camper's stomach. Ha Ha!