I guarantee to you that if the battery is registering 12.22 volts when the motor is running, that's because the alternator is dead.
Something has expired between the alternator, the voltage regulator, maybe a fuse somewhere, or the wiring got nibbled by a porcupine in the dead of night!
Well if its a wire two or from the field, or the regulator, then the alternator is probably not dead. Already posted an easy test to eliminate the VR possibility.
Agree in some parts of the country it could have been a porcupine in there, but all the signs here are just some well intentioned human.
