hey guys, i got a 16 hp craftsman tractor ithats 22 years old about. its got a battery that is 3 years old (about). during the first or two years of the batteries life the tractor would sit a whole winter in a 3 sided shed without being start and start fine afterwards. this past winter id start it once a week and this past month its been haivng battery trouble and its been dead for the past week and a half. today i charged it and charged it some more, got it to start once then it stalled, charged it some more and more and no luck, any ideas?