Best way to see if charging system is working is to have tractor at full throttle and measure the voltage at the battery. It should be above about 13.3v
I guess I would start there, 'cause if you don't have a good charge going, other things go wrong. Usually doesn't shut down the engine though, just won't turn on. Usually the seat safety switch is not working properly. Make sure it is turning on & off when you put pressure on the seat with a meter and the switch unplugged. Sometimes the connections get a little corroded over time too, so make sure they're ok.
Rattosh51
YT6800