What has worked for you? I read about removing them so they don't freeze and also leaving them because they will not freeze as long as they are kept charged. I have an AGM in my other boat and never worried about it. Now I have 3 huge deep cycle batteries and I don't want to ruin them. I could go out once a month and charge them while it is on the hard if that is sufficient. It doesn't go below -10F here. We get a lot of sunshine. Would a solar panel help? How big woild it have to be to have any effect on 3 batteries in parrallel? Thanks for your words of wisdom.