When our converter failed in our Class C Motorhome, we were about 4 weeks into a 6 week trip. We had a bunch of other small issues and I didn't feel like dealing with the converter. It was in a hard to get to place and I just wanted to enjoy the rest of the trip. I bought a car battery charger and used that to keep the battery charged. Once the battery was charged, I left the charger set to 2 amps and that kept the battery charged the rest of the trip. We were on Shore Power the whole time.
We camp seasonally now, but I still bring the battery charger with us just in case. Get a portable car battery charger and run it off your generator until you get a chance to replace your converter/charger.
-Michael