April to now -- dead battery?

here is a quote from an article I found at http://rvroadtrip.us/library/12v_system.php "Inactivity can be extremely harmful to a battery. It is a bad idea to buy new batteries and "save" them for later. Either buy them when you need them, or keep them on a continual trickle charge. The best thing to do if you buy them is to use them." It maybe at some point the battery may have been discharged below 11.57VDC and permanent damage may have happend.
Hope this helps some.

I cant seem to get this url link thing to work, can't cut & past