This is another instance that just goes to prove that you can never trust these batteries.
About two years ago, I saw a battery begin to smoke, and then burst into a nova star within 30 seconds. The battery was on a bench when it happened. It wasn't being charged, nor was it recently charged or used. Someone surmised that the battery must have been "damaged by being dropped" for the battery to have gone into self-destruct mode. But since it wasn't my battery, I didn't know if that could have been the situation.
I always thought it was possible for these things to fail at some point for no apparent reason, or without any indication. Now I know these batteries can pretty much melt down at any time.
David, thanks for bringing this to the attention of others. Sorry your RV was destroyed. What a bummer!