Dead coach battery.......any ideas?

[prescue]

99 Minnie, E450. Spent four nights in a park. Awoke today to leave and coach battery totally dead. Would not light the dash or warning buzzer when ignition on. Tried the auxilliary boost and it did nothing. Used the battery from my "toad" to jump and was only able to cause the starter to stutter. Engine would not turn over. Pulled a house battery to jump (confident that house batteries were charged). Likewise only caused the starter to stutter. Neighbor suggested that I allow the toad to run for a while connected to the coach battery. After about 5 minutes I was able to start the coach. Drove 175 miles to another park. Shut the engine off. It started again with ease. We shall see what happens in the morning.
Questions: (1) Any ideas what might have caused the battery to lose charge? There was no obvious cause such as lights, radio, ignitiion, etc. left on. One thought I had was that the battery simply shorted out and quit. It is 4+ years old. However, since it absorbed a charge in the 3 hour drive I'm not so sure. (2) Why did the auxilliary system fail me? I wondered if a shorted chassis battery would prevent the aux. power from reaching the starter, but I'm thinking it is unlikely that the aux. power is routed through the chassis battery (obviously I have no idea how the aux. system works).
All ideas appreciated.

[John Hilley]

First thing I would check is the battery terminal connections, probably got corroded in the hot humid weather. Next I would check the chassis ground point for a good clean tight connection. If you have poor terminal connections, the boost doesn't necessarily over come that problem as you are still using connections on the mode solenoid to the battery that could be bad.