Winter Battery storage?

I just bring both, fully charged, into a heated garage and do nothing until I need to used them. Have sat upwards of 12 months like this and never have had an issue for 5 year old RV type NAPA batteries.

Just got back from a week's hunting trip and they still perform flawlessly running the furnace, water pump and a few lights, but I do have a generator.

I store batteries by leaving them in place, charging them full up then disconnect so there is no drain. Come back in the spring. That has worked for the last 40 years on all my machines.

Years ago when I purchased my first Lifeline Batteries, Lifeline recommended a Xantrex True Charge 20 amp charger. The charger is expensive but Lifeline batteries are not cheap. The first set of 12 volt batteries lasted 10 years, I now have 2 - 6 volt Lifelines and am expecting the to get another 10 years out of them. I pull the batteries by November, put on charger, and usually reinstall around May here in the NE USA.

Lots of opinions on this, and many good/correct ones.

I, personally, leave the batteries where they are, and connect a $20 Schumacher battery maintainer from Walmart when they're in storage. I generally get several years out of each of my batteries. Ironically enough I have one or more batteries in everything that's in my barn, EXCEPT the camper! If my camper had a battery, I would give it the same treatment as the truck, trailer, five tractors, and lawn mower.

http://www.harborfreight.com/automatic-battery-float-charger-42292.html?ccdenc=eyJjb2RlIjoiMTkxMDMzNzUiLCJza3UiOiI0MjI5MiIsImlzIjoiNS45OSIsInByb2R1Y3RfaWQi%0D%0AOiIxMTQxIn0%3D%0D%0A

I was going to buy this and wire the two batteries together, I says it has automatic shut off
I also have a 15 watt solar panel that could work

A $30 trickle charger from WalMart will maintain your batteries as well as a $300 everything-but-makes-coffee charger. A stored battery is slowly eating itself alive, that's just how batteries work if not kept charged. An AGM battery doesn't even need water to be added and can be installed inside, unvented, upside down, in an airplane, and under your dinette...But I digress.