Bike would hardly turn over, so I hung the tender on it overnite, and  the next day, it never quit charging,...very unusual !
I thought....oat oh ! you don't suppose,.....right on,..... bone dry, .....creamated !! I couldn't believe it,.....or,...yes I could,....its been 2 yrs since I checked the water, dam,....thats not like me, must be age ??
Anyhow, filled it,.....just as big a pain as I remember it was 2 yrs ago.
Charged it,.....now the charger went to float mode after 4 hrs. Then after just setting a couple hrs, it started the bike like a million bucks !
The battery is 4 yrs old,.......time will tell.

Check your battery once a year ! (what a pain!!)
And if you replace, do it w/ a "Big Crank" waterless !