Another electrical gremlin

[bncinwv]

We made it back from the Southern adventure and went to connect the electric and noticed that we had a minor problem.....no ELECTRIC!!! Dangit!! A little history here may be worthy. On the return trip we left the fridge on to preserve the foodstuffs and during the sixteen hour trip the battery died. I have known we have had battery problems for a couple of months and will be upgrading next Spring with a new battery and hopefully a smart-charger type set-up. Now back to the post.....the problem with the electric was that either the breaker at the house (15 amp) tripped or the GFCI switch we were plugging into tripped. The dilemna was the battery is dead so I can't get the rig off the truck since the legs won't extend and I also can't unload all of the Black Friday goodies from the living room since the slides can't be extended. I always thought that the umbilical cord from the truck also charged the battery although very slowly?? After trying to troubleshoot the rig (thinking that something was left on that was tripping the 15 amp connection), I finally dragged the extension cord inside the house to a non-GFCI outlet (I think this outlet was on a 20 amp breaker) and everything returned to an operation state. I don't know if a completely dead battery would cause this by drawing too much power through the charger?? Any thoughts?? It is not a function of the extension cord, or the breaker strength since these common factors have not changed from previous hook-ups at the house.
Bingo