Let me state at the outset that I'm no engineer, so I only have my own (non-lithium) experience, and what I read. And from that, I don't think lithium batteries are ready for prime-time ... in most general-purpose motorcycle applications.
In this month's Motorcycle Consumer News
, which I received in the mail a few days ago, there's a reader question about bike charging and lithium batteries. The response by MCN's tech guru confirms my belief that I'm staying away from lithium for quite a while.
A pic would be way too difficult to read here, so I've scanned in that almost full-page Q&A, and put it up as a PDF page on my web site, here:
Chargers and Longevity:
I used to use a couple of Battery Tender Jr smart chargers, for bikes and riding lawnmowers. When one gave up the ghost after about a decade, I bought an Xtreme model about three years ago:
XC100-P Xtreme Charge 12V Battery Maintenance Charger Desulfator
(BTW, PulseTech, the maker of that, is currently giving away a battery tester if you sign up for its mailing list. See Battery Chargers and Battery Desulfators by Pulsetech Products
I plug my XCT into a smart charger every day -- not just over the winter -- that the bike's at home, i.e., when I'm not traveling out of town. See pics attached here.
I've been doing this on bikes for many years, and usually their batteries last longer than I own the bike. I did have to buy a new battery for a Valkyrie Interstate, but I had that bike for seven years.
So, maybe with five years on a battery it might be time for a new one. Or maybe not. If you use a voltmeter to measure the bike-off voltage periodically, and notice that it's decreasing, that might serve as a poor-man's load test, and give you an indication of a problem. Or you could also note if it's taking longer than before for a smart charger to get to its happy place, once you hook up the bike to it. Most smart chargers change from a blink to a steady light -- or vice versa -- once they change from charge mode to float mode, and you could pay attention to that time interval.
I suppose you could also take the battery out, and have it load tested, if you know some place that does this, and that you trust to do it right.