Diagnostics · Expert tip
12.6 V at rest = healthy battery
Below 12.2 V is half charged; below 12.0 V is being damaged.
The expert tip
- Measure 30 minutes after driving
- 12.6 V+ = fully charged, 12.4 V = 75%, 12.0 V = 25%
- Load-test a battery that reads fine at rest but cranks slow
Source: Battery experts
Apply tips that match your car and manual. For anything safety-critical or high-voltage, use a qualified mechanic.