Daniel Menard
I do not see that anyone tackeled your problem. I think you may have a generator over charging. Causes, stuck contacts in the regulator or bad ground on regulator. for stuck contacts remove cover and pry open contacts or hold open with a piece of paper. for bad ground check from reg body to tractor frame, should be zero volts, with tractor running, if not check the small braided wire that grounds reg. I had the same problem, mine was the braided wire.
H.C.