Engine cranks slowly
Clicking sound when turning the key
Dashboard lights dim or flicker
Headlights are weak
Battery warning light is on
Car needs frequent jump-starts
Electrical accessories act erratically
Battery case is swollen or bloated
Battery terminals are corroded
Battery is leaking
Rotten egg smell near the battery
Battery is older than 3 to 5 years
Battery voltage is low when tested
Car starts fine after charging but fails again soon
Visible cracks or damage on the battery case