When the car battery needs to be replaced:

1. The car is more difficult to start than usual, which may be a sign that the battery is about to be scrapped;

2. The headlights dim when idling. This is because the charging power of the engine decreases during idling, and the battery with reduced performance also needs to supply power to the electrical equipment in the car, and the power distribution of the headlights outside the car will drop significantly;

3. The battery fault alarm light is on, you need to go to 4S or repair shop to check and replace;

4. Abnormal sound when starting: due to the weak discharge capacity of the battery and the poor operation of the starter, a squeaking sound is issued;

5. Changes in the observation port: There is an observation port on many maintenance-free batteries. There is a light to show whether the battery is working well. The green is good, and the black needs to replace the battery;

6. If the battery is bulging or leaking, it should be replaced in time.