Our bus, which stays contentedly in the bus barn, is continuously powered and its batteries kept charged by the inverters. I was led to believe everything was in good shape until we had a utility power failure last week. When I checked the coach the next morning, I found the batteries at a pitiful 7.8 volts. It seems that even when being charged, they can fail. A quick call to Trukster revealed that, based on the code stamp, the batteries were 8 years old and had reached the end of their lifespan.
Fortunately, Tom came to the rescue. His price on Lifeline 8D batteries was at least a hundred bucks cheaper than any online source I found. He ordered them last Thursday, and they arrived today. Many thanks to Tom!