Battery recharge after dry camping trip

I hooked up my normal battery charger and in a matter of a few hours on 10 amp setting the SG came up. I think every one is right about the WFCO charging slowly because when I checked the voltage the batteries were being charged at it was at the lower 13.6 volt charge. Good to know though. There is only one dry camp area around here and that is at the beach. It's kinda cool being self contained. I ran the radio most of the day, the tv off of a small inverter and even charged our cell phones with no power problems on a weekend trip.