Both our boat batteries, one new last season and one at least a season old, I imagine, sat in the garage all winter. Hooked them up to the plain old Sears automotive charger prior to putting 'em back in the boat this spring. The older battery was a bit reluctant to take a full change, but, ultimately, it did. I start on "both" and the ammeter usually settles back down to "0" pretty quickly, despite the fact we've been experiencing hard starting, the 1st start of the day, so far this season. (The boat has a TrueCharge 10A [per battery] charger running off of shore power.)
We've got a commercial lawn mower. 16HP Kohler engine. It's got a fairly large (for a mower) battery in it. It sits out in the micro-barn from the last cutting in the fall to the first cutting in the spring. The original battery, after about 3 seasons of that, needed the charger for the first start in the spring. It wasn't until season 5, I think, that it finally gave up the ghost and wouldn't hold a charge anymore.
I find it hard to believe storing a new battery for several months off a charger did any serious harm to it, but I'm willing to be proven wrong.