First question is why a new battery in 3 years they should last at least 5 years and many go 6 and 7.
For a battery to only last 3 years would rase question on how it was cared for when bike was not ridden and if connection are good.
One problem seen alot of is the connector at engine from the stator becomes corroded. I had it happen on 94 FXR over time battery never really charges up fully.
They also make our Die Hard batteries now, very good product with more CCA than our last supplier:s
Deka may make both, but is it accurate to say that the two products are the same? Does Deka make different qualities for different suppliers, thus accounting, in part, for the differences in prices? Or is a Die Hard of a given size equivalent to a Harley battery of the same size?
FWIW, I used to buy Die Hards for my FXRS, and had to replace them about every 14 months or so. They didn't wear out so much as short out. When they went, they were gone! That was a few years ago, however.