Aarrgghh! The frickin' coolant pump went wacko and decided to run all the time. That's what ate up the battery. First major item I've had to address on this vehicle, now at 113,000 miles. It may just be a "water pump", but I consider it major at $2200.
The auxiliary battery with install and coding came to $535, which doesn't bother me as much, considering the battery is over $300 by itself. Good thing I always seem to get at least 7 years out of the batteries.