Should be no different than a battery on a riding lawn mower. I have 2 John Deere's, both have batteries, both in an unheated garage. I keep a trickle charger on them all winter. Never a problem with them. They fire up the mowers in the Spring like fresh ducklings popping from it's egg shell!
Of course keeping them in a warmer environment is always nicer, but not necessary if the battery is charged.
I also live in Indiana. I leave my battery on the trailer and never take it off. Plugged in at home all the time. Snow, Ice, or tornado, it's always there. Charger on the camper maintains it. No problems.
Got the new 5er 2 weeks ago. Curious how this puppy will do through the winter. TT's always did just fine.