I hadn't thought about this being under warranty. 2015 so it'll be 3 on Oct. I just called the dealer and was told the battery should last about 24 months. No warranty after that. The longest I've let it set without a tender is 4 days and it wouldn't start. So they offered me a discount on a higher amp agm type. I get the military or their discount. Either way 10% off. I sure wonder if something else is pulling it down.
The battery is covered by the new bike factory warranty, which of course is only two years. Replacements from Harley are warranted for one year.
It is not uncommon for Harley batteries to fail early, and it's a problem you can see in other brands of vehicle starting batteries in cars, trucks, and bikes. Vehicles in general have higher demands placed on the electrical systems these days, which affects the life of the batteries. Another big factor is the constant cost cutting by the battery manufacturers, which can lead to internal physical failures of things like cell connectors and plates. It's something I've seen in many different brands over the past ten years, and it's a crap shoot whether you get a good one or a not-so-good one.
Considering that even the high priced offerings tend to have similar battery life variations, I look at it this way. I can buy two batteries of equal or greater CCA from a place like Battery Mart for about the same amount as one battery from the Harley dealer. I've gone with the Deka brand, made in the USA by East Penn Mfg. They come with the same warranty as the Harley battery, and they will ship to your door within a day or two of the order. If you're on the road and it fails, buy another at one of the many auto parts stores, motorcycle parts stores, Wally World, etc. There are many different names on those batteries from East Penn btw, Deka is just the name they use. Even if you don't want to haul the old one home and then ship it in for warranty consideration, big deal. You paid half as much as the Harley battery, so even if you have to buy another you aren't any worse off than if you had bought the overpriced one from the Harley dealer.
If you want something that has a higher CCA than the Harley battery, and still save a little money, look at Yuasa. Yes it's a Japanese brand name, but they are made in the USA these days. GYZ32HL, 500 CCA, can be found for about $140 on Amazon and other places.
Jerry