Batteries and Winter Storage for Basecamp with Solar

[JohnDDobbs]

Hi. I have a 2019 Basecamp (not X) with factory installed solar. It has the Atkinson solar controller, and two panels on the roof.

So my question is about the batteries (two Lifeline AGM's) and storage for winter. I know that uncharged batteries can freeze (and that is bad). My understanding is that charged batteries are less likely to freeze (and temps don't get horribly cold here in Western Colorado).

And I've read that if you pull your batteries and store them in the garage, you should charge them occasionally.

So if I can leave them in the RV where they get charged every day and they won't freeze, why should I go to the trouble of pulling them out?

Is there something about storing outside of the RV that lengthens the life of the battery?

What do other folks with solar do with their batteries in the winter?

Thanks,
John