I ask. Why do I need a special charger for lithium batteries, if the motorcycle's alternator is the same and gives the same type of charge as a normal acid / lead battery charger?
Good question! I've read a plausible answer, but . . . forgot the essence of the response. A warning sticker on a Shorai battery may hold a clue; says to avoid at all costs a battery charger with a high-voltage, "de-sulfation" setting. The "special" lithium chargers may be strictly voltage-limited.
I think, just possibly . . . a special charger is nice to have (maybe extends battery service life), but not essential.
One thing about lithium batteries, in my experience (lithium-powered drills, impact drivers, vacuum cleaners, chain saws, and MOTORCYCLES), these power sources seem rather BINARY: The batteries are either capable of delivering full power, or they're effectively shut down totally--there's no graceful degradation, batteries are essentially ON, or OFF.
True story. KLR650 with Shorai lithium battery, in storage for over 2 years. Rolled out of the storage factility (2 + year-old gasoline; don't know if stabilized or not), and . . . started immediately! After a while, started again. Then . . . wouldn't do ANYTHING. Hardly a glow from headlight, hardly a buzz from the starter solenoid. Battery later charged with an ordinary, garden-variety charger, on the, "2 amp" circuit; now appears to hold a charge as when new.
Oh, yeah. Some tell horror stories of lithium batteries failing in severely cold environments; on the Internet, must be true!
Lots of sources for motorcycle lithium batteries; Cycle Gear carries Shorai, from whence the anecdotal battery came.