How to Distinguish Between Good and Bad Car Batteries?
1 Answers
Methods to determine the condition of a car battery: 1. Check the battery status through the observation window. Green, yellow, and black colors indicate good battery condition. Yellow means the battery capacity is insufficient, while black indicates battery damage. 2. Assess the battery's usage status. If the battery fails to hold a charge, frequently runs out of power, or cannot be recharged, it signifies damage. 3. Inspect the battery's external condition. Noticeable bulging or swelling on the sides or white powdery substances around the terminals indicates performance issues. 4. Use a multimeter to measure the battery voltage. First, select the DC voltage setting (20V range). Connect the red probe to the positive terminal and the black probe to the negative terminal. Measure the static voltage before starting the car; it should be between 11.8V and 12.8V. A reading between 11V and 11.8V suggests slight discharge but still allows starting. Below 11V indicates severe discharge, preventing the car from starting, requiring a dedicated battery charger. If the voltage doesn't return to normal after charging, the battery is internally aged or faulty and needs replacement. Measure the dynamic voltage after starting the car; it should be between 13.2V and 14.8V. Abnormal readings (too high or too low) suggest a faulty voltage regulator in the alternator, requiring replacement. Measure the minimum voltage during startup; it should be above 9V. Below 9V may cause difficulty or failure to start, necessitating battery charging or replacement if the issue persists.
