I purchased a Scag Cheetah 61" (Kaw 921) mower in about April '13. Here it is some four years and seven months later and I think my battery is dying. I cut my yard yesterday and had to put a charger on the battery to start it. This is the second time I find that a battery charger was needed to start the mower in order to cut my grass. Based on two hours of run time yesterday, I feel the battery should have been fully charged. I checked the battery this morning with a voltmeter, and it registered 12.44 volts. I tried the starter and it just clicks. How long should an AMG Lawnmower battery last ..? What is the minimum voltage needed coming from the battery to start the engine..? How can I tell if the engine charging system is not charging the battery...?