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.
Friday, August 3rd, 2012 AT 9:30 AM