I have a 3 year old John Deere L110 that is not charging the battery. Over the summer, the engine has cranked slower and slower, until it finally would not start. I could jump it with a bump box no problem. Plenty of cranking speed. I also put a trickle charger on the battery for a couple days, removed the charger, and it cranked like normal a week later. I do not notice an appreciable different in voltage running vs not running. I switched my volt meter to AC volts, and it registers 12 volts not running, 14-15 volts running. Any ideas? Is there a diode or voltage regulator that maybe went bad? The dealer says it is the battery (which is OEM), but it obviously is not. It holds a charge just fine, and still has plenty of cranking power.