Your car’s battery is essential to its operation. The battery is your car’s source of electricity. Without a properly functioning battery, your car will die.

A dead car battery is not ideal in any situation. It doesn’t matter whether you’re running to the grocery store or in the middle of a cross-country road trip.

You can save yourself hours of frustration by checking your car battery voltage regularly and getting a car battery replacement when necessary.

Ideal Car Battery Voltage Range

Car batteries are 12-volt DC batteries. The ideal voltage for a car battery is 13.7 to 14.7 volts when the car is running. When the engine is not running, the voltage should read at 12.6 volts.

A car battery that is not fully charged will read at the following intervals:

• 12.4 volts at 75 percent
• 12 volts at 25 percent
• 11.9 volts at 0 percent (completely discharged)

When you compare your car battery voltage to the ideal battery voltage range for that specific type of car battery, you can learn a lot about the condition of your car battery.

Keep in mind there are different car battery sizes and make sure you are comparing your car battery voltage to the ideal range for its size.

Unfortunately, you can’t learn everything about the condition of your battery just by checking its voltage. Knowing your car battery range is only a starting point.

To really understand the overall condition of your car battery, you will need to run a car battery voltage test.

How to Test Car Battery Voltage

Did you know a healthy car battery may show a low voltage reading if it is discharged? But this isn’t an indicator of the internal health of the battery.

The best way to understand the condition of your car battery is to do a car battery voltage test using a car battery tester.

You can run this test by measuring your car battery’s voltage and comparing it to past results. This will tell you whether the car battery is dying.

To run a battery voltage test, the simplest way is to use multimeter. To begin, set the multimeter to read DC voltage and set it to above 10 volts.

Next, take the voltmeter’s positive cable and connect it to the positive terminal on the battery. Then, take the negative cable and connect it to the negative terminal on the battery.

It’s best to have someone else start the car while you read the meter. As the vehicle starts, the number on the multimeter should begin to drop. As long as it stays above 9.6 volts it’s still a good battery.

Using a multimeter will give you an accurate reading of your car battery voltage. If you get a negative reading, it just means you have mistakenly reversed the cables.

Testing Your Car Battery Without a Multimeter

It’s not possible to get an accurate battery voltage reading without a multimeter. But there are a few things you can do without a multimeter to check the condition of your car battery.

To start, turn your car off and then turn your headlights on. Make sure the car is in park (it helps to put the parking brake on for extra assurance). Then have someone else turn on the engine.

While they are starting the engine, stand in front of the car and watch the headlights. If they become dimmer when the engine is starting, it probably means there is not enough charge left in your battery. 

How to Test Car Battery Load

Testing the voltage of your car battery will tell you if the battery is charged. It will not tell you much about the overall health of your battery.

Performing a car battery load test is a more accurate way to get a sense of your battery’s internal condition. This can be done with a load tester.

A load tester is a special type of equipment that determines voltage while a load sits on the battery. Load testers are surprisingly affordable as far as automotive equipment goes.

To use a load tester, apply a load to your fully charged battery for 30 seconds or less. If the voltage drops below 9.6 volts during that time you need to take it in for a car battery replacement.

How Do You Know When It’s Time to Replace Your Car Battery?

Many things can cause a car battery to lose voltage or die. Leaving the headlights or interior lights on overnight can drain your car battery. Running too many accessories at the same time can also cause battery distress.

There is something you can do to remedy a weakened car battery. You can jump the battery with a stronger one. All you need to do is connect cables from the weak battery to the strong battery.

Make sure to keep the batteries connected for several minutes. This will ensure a successful transfer of power.

Next, use your voltmeter to test the weaker battery’s voltage. If the voltage remains weak, that means the battery is dead and needs to be replaced.

What You Need to Know About Car Battery Voltage

Car batteries are the nerve center of your vehicle. Without a properly functioning car battery, your car won’t run.

To best understand the range, health, and condition of your car battery, you should run a car battery voltage test. For a more accurate voltage reading, run a car battery voltage load test.

If testing your car battery indicates that it is at low voltage, it is time to replace your car battery.

If you liked this article, you’ll enjoy the other articles in our automotive section. Check out our guide to windshield replacement next!