Amazing that now yours has failed to start - exactly like mine. I went to the car tonight and retrieved the battery. It is charging now. Tomorrow I will get a ride to the car, and re-install the battery. Hopefully the car will start so I can get it home and check it out.
I also suspect the regulator and brushes, although I checked it last week and measured 12.5 volts with the engine off and 13.87 volts with the engine running.
Tonight the battery showed 11.5 volts. Is that not enough to start the car?