[Bob KellyIII]

I would say that there was a cap on the vent of the battery that was not removed after the battery was filled and the charging increased pressure inside the battery until it blew the cap off... your lucky I've had battery's split wide open because of that !
if it holds a charge it's good to go ....if it doesn't leak
some of these new batteries do not have a vent to un plug and they recommend that you leave the caps off till they are fully charged if that is the case if you put the caps back on and then charged it that was the cap venting ! another you were lucky it could have split the battery... but no harm done as long as the case didn't crack your good to go !
I've been known to leave a battery on the charger for an overly long time
and that is not good for them at all..... if a 3 hr charge doesn't bring the battery up to 12~13 volts just replace it ! my charger is 2 amps and I can manually set it to stay on for however long I want..... I've brought back dead batterys because of that but that is never guaranteed !
In my mind an automatic battery charger is only good if you know your not going to be there to turn it off when the time is up....
I've had good batteries and bad batteries from several different companies
I've paid a bunch of money for some and the cheapest I could get and there is NO consistency in batteries it's a "pig in a poke" a roll of the dice if the one you buy is going to be any good or not.... and paying more money for them does NOT guarantee quality..... though it might help your odds and perhaps any return policy.....
I went into auto zone looking for a GOOD battery for my XS650 Yamaha
I told the guy I wanted a battery that wasn't going to have to be replaced next year he brought out one that cost $119.00 if I remember right but it lasted 4 years and was still good when I sold the bike !
I also got one from Walmart that was on sale for $23.00 and it lasted for years.... so you never know !
Bob......