read parts 1 and 2 .
http://www.marxrv.com/12volt/12volt.htmSULFATION : This battery may have taken a hit. You might have done damage to your battery. Use the correct charger and process to attempt to restore it. It might not get back to 100% and its life may have shortened.
Sulfation of a battery As already mentioned, disconnect or remove it to a warm dry storage room (cold is also your batteries enemy) during long term storage periods.
Also mentioned, toggles : Only because I often boondock without hookups, I have installed toggle switches on my radio/tv/tv antenna/and detectors ( I use portable detectors in its place)
All the above 12v items together had a draw of approx. 1 amp x 24 hours a day.
That's a lot of juice to loose each day for something to just sit there and look pretty . :E
DESULFATOR and TEMP SENSOR
difference between Battery Tender vs Battery Minder