[Tx Firefighter]

Intermittant problem is usually the voltage regulator.

Alternator failing usually just happens all at once.

Everybody praises 1 wire alternators, but they do have downsides. They always stay energized, so they slowly deplete your battery over time if you don't drive it often enough.

Also, when you start a vehicle up with a 1 wire, you have to rev it up to get it to start charging each time.