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Can a car battery have 12 volts but still be bad?
If the battery cannot reach higher than 10.5 volts when being charged, then the battery has a dead cell. If the battery is fully charged (according to the battery charger) but the voltage is 12.5 or less, the battery is sulfated. If your battery cannot even reach a full charge, consider it bad.
How do I know if my alternator is overcharging my battery?
Symptoms of Your Car Alternator Overcharging:
- Car Battery Voltage Gauge Reading is High. You notice a high voltage reading on your cars vehicle’s dashboard.
- Car Battery Gets Hot When Charging.
- Your Headlights Burn Out Quickly.
- Your Car Battery is Bulging on Sides.
What should battery voltage be with engine off?
A fully charged battery should read 12.6 volts with the engine off. The reading of 12.1 means the battery is run down a bit or is bad.
What does it mean when battery voltage is below 12.6V?
If the voltage is below 12.6v it indicates that the battery isnt fully charged or has a fault. The voltage doesn’t have to differ much from 12.6v for it to indicate a discharged battery. At 12.2v the battery is in effect 50% discharged. When you start your car, the battery provides the necessary power to the starter motor to turn over the engine.
Why does the voltage of a car battery decrease?
Age: As your battery ages and is used, its ability to hold charge will diminish, with a resulting decrease in the voltage. State of charge: The voltage of your battery will change as it is charged and discharged. Understanding at what point it is in a charge cycle is important when determining what the voltage should be.
How many volts does a car battery hold?
A good battery will normally hold about 12.8 volts when fully charged. More if let the engine has just been running and charging the battery. 12.7 is a charged battery. 12.4 is knackered. Most motor factors and Tyre companies will do a free battery check.