Check for a battery warning light on the dashboard
Test battery voltage with the engine off and running
Look for dim or flickering headlights
Listen for whining, grinding, or squealing noises
Check if electrical accessories act weak or inconsistent
Inspect the alternator belt for looseness, wear, or damage
Look for burning smell or overheated wiring near the alternator
Test for a dead battery after driving
Use a multimeter to check charging voltage
Have the alternator load-tested at an auto parts store or shop