Yes, the Southwire 21010N digital multimeter can test a car battery's voltage, which is a fundamental diagnostic step. It measures DC voltage (VDC), the critical metric for assessing a battery's state of charge. However, it's important to understand its limitations: it can only measure voltage at rest, not the battery's ability to deliver high current under load, which is what a dedicated load tester checks.
To get an accurate reading, set the multimeter to the DC voltage setting (V with a straight line, not a wavy line). A healthy, fully charged car battery should read between 12.6 and 12.8 volts when the engine is off. A reading below 12.4 volts indicates a partial charge, and anything at or below 12.0 volts suggests the battery is discharged or failing.
Here's a quick reference table for interpreting your voltage readings:
| Battery Voltage (Engine Off) | State of Charge | Recommended Action |
|---|
| 12.6V - 12.8V | 100% (Fully Charged) | Battery is in good condition. |
| 12.4V - 12.6V | 75% - 100% | Acceptable, but monitor. |
| 12.2V - 12.4V | 50% - 75% | Battery should be recharged. |
| 12.0V - 12.2V | 25% - 50% | Battery may be failing; test after charging. |
| Below 12.0V | 0% - 25% | Battery is likely dead or has a bad cell. |
For a more thorough test, check the voltage while a friend cranks the engine. If the voltage drops significantly below 10 volts, the battery likely lacks the necessary cranking amps to start the car reliably. While the Southwire 21010N is a great tool for a basic health check, a professional load test at an auto parts store is the definitive way to confirm a battery's overall health.
