Wow that sucks. Only 2 years. I know some people in hot environments only get a couple of years but I'm hoping for way more. Looks like this motorcycle "hobby" is going to be as expensive as a boating one.
There was a thread on the Raider forum but right now the site is down/slow... Anyway from what I remember it was the usual suspects like Yuasa. They also threw out the newer technologies but those were some pricey batteries.
Check what your dealer has/recommends but if it is the same as OEM assume you'll only get 2 years out of it and factor that into the cost. I think one website has an in-house brand(Scorpion maybe...) that was a decent price.
If you had posted a week or so from now I'd have more info from the MC show here. Sorry...