2001 Ford Escort

I was reading your article on the alternator. What I don't understand is if the vehicle is being operated by the alternator, how will the battery die if there is an alternator malfunction? The battery is designed to hold power. So even if it has a partial charge, won't the battery hold it? Now that's with the engine off. But at the same time, How is the battery powering the vehicle if only the alternator is designed to power it?
August 3, 2012.

Batteries have a life span and the internals deteriorate over time. Even if the alternator is charging it, it can fail if it cannot hold the charge.

The battery would hold cahrge but what it holds could be sufficient for lights etc but not high current draw for the starter.

Battery is for cranking and complementing th alternator. Whatever the alternator is not able to provide, the battery backs-up.

Aug 3, 2012.

Above link provides a better description of the alternator.

Aug 3, 2012.