A good 12V battery voltage depends on whether the engine is running or not.
Understanding 12V Battery Voltage
Here's a breakdown of what constitutes a good voltage for a 12V battery, based on different scenarios:
- Engine Off (Resting Voltage): This measures the battery's state of charge when it's not actively being charged or discharged.
- Engine Running (Charging Voltage): This reflects the voltage while the vehicle's charging system (alternator) is working.
Good Voltage Readings:
| Condition | Voltage Range | Interpretation |
|---|---|---|
| Engine Running | 13.7V - 14.7V | Indicates the charging system is working correctly. |
| Engine Off | 12.6V | Fully charged battery. |
| Engine Off | 12.4V | Approximately 75% charged. |
| Engine Off | 12.0V | Approximately 25% charged. |
| Engine Off | 11.9V or lower | Fully discharged. |
Therefore, according to the reference, a perfect voltage with the engine running is between 13.7 and 14.7V. With the engine off, it should be 12.6 volts.
