A car that won't start usually gets blamed on the battery, but the alternator is responsible for keeping that battery charged. If the alternator fails, even a brand-new battery will go dead.
Signs of a bad battery
Slow cranking, clicking, the car starts fine after a jump and keeps running, or the battery is more than three years old.
Signs of a bad alternator
The car dies while driving, headlights dim and brighten with engine speed, there's a whining or grinding noise, or a new battery dies within days.
Get it tested
A proper charging system test checks both in a few minutes. Our technicians test the battery, alternator and starter on every service call so you only replace what's actually failed.