The ideal percentage for your battery depends on the type of battery and its use, but for a car battery, it's best to maintain it above 50% charge to ensure reliable starting. A healthy car battery, when the engine is off ("resting voltage"), should ideally be at 12.42V or higher, which corresponds to an 80% state of charge according to Kwik Fit.
Here's a breakdown of the state of charge based on resting voltage for a 12-volt car battery:
12-Volt Battery State of Charge
| Voltage (Engine Off) | Volts per Cell | State of Charge |
|---|---|---|
| 12.42 V | 2.07 V | 80% |
| 12.32 V | 2.05 V | 70% |
| 12.2 V | 2.03 V | 60% |
| 12.06 V | 2.01 V | 50% |
Maintaining a Healthy Car Battery
- Regularly check the voltage: Use a multimeter to check your car battery's voltage periodically.
- Avoid complete discharge: Try not to leave your car with the lights on or other accessories running for extended periods.
- Long periods of inactivity: If you're not driving your car for a while, consider using a battery maintainer to keep it charged.
Keeping your car battery at or above 50% charge (ideally around 80% or higher) will prolong its life and ensure reliable performance.
