Hi, I have a JD SST16 that is having some issues and I'm not sure if it's the battery or the charging system although I think it's the latter. Today the tractor wouldn't start so I put it on the trickle charger and waited a few hours. I came back and it sparked right up. I cut a lawn and tuened the tractor off and it wouldn't start, voltage was 9V. Trickle charged it again and the voltage was 12.24V and while running was about 11.8V, I turned the lights on and it dropped to 11.6V. I'm thinking the charging system took a dirt nap. Are the charging systems complex? Any ideas? Thanks, J.