I went ahead and purchased a new battery and all seems well. Regarding your statements about "the battery surrounded by hot oil in the oil tank," makes me think my crotch cooler isn't helping matters pertaining to keeping additional heat around the battery??

 

I'm coming up on 4 years on my Fatboy with the original battery. Still running strong, and I put it on a tender only if it's going to snow for a week at a time.

 

Ive heard the newer batts put out by the moco dont last as long.
Ive not noticed this first hand though, but theres a thread on this some where.

 

'07 Springer Classic. Just replaced the original battery yesterday. Was fine if I rode it daily, but would hold charge after 4-5 days. Tender on, it was good to go if it sat for several days. Finally load tested it and determined the battery was done.
Previously only used the tender in the cold months.
But, never had a problem until just a few weeks ago.