I used to take ours home and keep them in the garage on a block of wood.. It's still cold in the garage, but very rarely below freezing... no problems, but had the work of hauling them back forth etc. I only charged them in the spring before taking them back over to the boat.
We store inside cold storage... so the last 2 years once charged, I've unhooked the batteries and left them.. no problem just be sure the wires are unhooked.. (I only unhook the positive terminal) This year, new location inside cold. They use the same building as the indoor heated storage.. I was told it didn't drop below freezing in the unheated side either.. no brainer.. unhooked and leave on the boat etc.
Arctica, based on your location in Minnesota... if you leave them, I'd be sure to put on some sort of charger.. solar if you can keep the snow off it.. otherwise, I'd bring them home and keep them warm and trickle charge occasionally.
I agree, no Foo Foo batteries.. but an expensive ticket not to take good care of them.
I was in Minnesota once in the winter time.. WOW, talk about cold.. made our winters in Cleveland seem like a walk in the park. They had 110v outlets on the parking meters to plug in block heaters... it was a slow start in the morning at the hotel.. that is for sure. BURR!!!!
Arctica, bottom line, if they’re not hard to get out and transport, I’d bring them home.