RE: Garden Tractor Battery
Well, that was fun, but I still don't know the amp-hour capacity of my garden tractor battery.
I have been told to dump my battery in favor of a Gel-Cel by a HAM. I have at least three gel-cels; I wanted to know the AH capacity of the tractor battery. I first got my ham license when I was 13, a long time ago.
Chargers. The center-tap rectifier as drawn will tend to try to charge to the peak voltage of the rectified ac output, less diode loss, transformer loss etc. Approx (15x1.414) - .7 = 20.51 volts at no load, somewhat less loaded. The .7 is gesstimate of the diode voltage drop. A transformer at about 11 volts either side of center tap might be better. Unless you just enjoy building the stuff, it's safer to go by a good charger.
Larry