Battery dead

Just got back from a 2 week trip to Northern California. Stayed at Lassen N.P. and near Lake Tahoe. All dry camping. My 25' Alumascape trailer served us well until the last morning when we awoke our batteries were dead. My batteries (2) are 12 volt deep cycle and just 2 years old. I had been running my little Honda 650 watt generator 2 hours every other day and the trailer's monitor panel said the batteries were at full charge the entire trip until the last morning. On the last morning the monitor panel said they were completely discharged. We don't use a lot of power, just a couple of LED lites and the furnace does run about an hour each morning.
So I basically have two questions: Is 2 hours of running generator enough time? Is my monitor panel accurate? I have never seen the trailer's battery monitor panel show anything other than fully charged or completely discharged.
I forgot to mention that I connect the generator to the converter which is a Parallax 55 watt.
Comments anyone??