Dude you need to grow up. Don't get mad. It's not a popularity contest. Just a matter of who's right and who's wrong. I'm also not sure why you even comment on the 21+ forum when you have no experience with the platform.
You don't add anything meaningful to the discussion except wrong answers. And then clutter the post with name calling like a little kid.
Alternator runs the car and charges the battery. The battery only exists to start the engine. An alternator can keep a car running by its own voltage output. Battery has nothing to do with that except to be a load on the circuit when vehicle is running. If a car is started and battery dies because of a bad cell etc the car won't just die. Why do you think an alternator puts out more than 12 volts? Gotta know what your talking about. Now if an alternator dies while the car is running the car will die as soon as the battery dips below 12v.
But whatever dude over here knows things lol..smh
Here's another link to clear it up for you. It has pics too.
https://theengineeringmindset.com/car-alternator-how-alternators-work/