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How Many Volts Is A Car Battery? What’s The Ideal Range?

How many volts is a car battery? The straightforward answer is: car batteries are 12-volt DC batteries. But, the voltage is not a fixed number. In fact, there is a whole car battery voltage chart, and if you want to know about the overall condition of the battery, a voltage test seems to be the right option.

Regular testing of electrical systems and batteries is a part of automotive maintenance. Do it at least twice a year to decrease the chance of their sudden failure. A voltage test will help you determine the battery’s health.

How Many Volts Is A Car Battery? The Ideal Voltage

Measuring the voltage will give you an idea about the current charged status of a battery. Comparing it to the ideal car battery voltage range will help determine the battery’s condition.

A fully charged car battery voltage (without being plugged into an external device) ranges from 13.7 to 14.7 volts. It will drop to 12.4 volts when the charge is 75% and 12 volts when it is at 25%.

normal car battery voltage
Testing voltage with a voltmeter


What is the normal car battery voltage when it runs out of juice? In that case, the voltage drops to 11.9 V. So, the voltage has to be at least 12 for a car battery to have the functioning capacity.

How To Test A Car Battery Voltage

Using a voltmeter is the easiest way to measure a battery’s voltage at a given time. It is helpful because you can compare the readings with past results to deduce whether the battery is running fine.

Set the voltmeter to its maximum value and touch its positive and negative cables to the positive and negative terminals of the battery, respectively. If the device is functioning, it will show accurate readings.

Don’t have a voltmeter to test how many volts is a car battery? Well, you can still check the battery’s condition by kicking the engine off and turning on the headlights. It will not be possible to find out the voltage readings, though.

  1. Dim headlights signal drawing juice from the battery and no charge production from the alternator.
  2. Brighter lights when cranking up the engine imply production of current by the alternator to some extent but not enough.
  3. Similar brightness during engine revving indicates a properly functioning battery and alternator.

Car Battery Load Test

A working battery will generate between 9.5 and 10.5 volts in a span of 30 seconds in load testing. A reading in that range indicates a healthy battery that can store adequate power and run the electric devices in the car smoothly. You will need a battery load tester to perform the inspection.

car battery voltage chart
You will need a load tester

What should you do if the battery fails the load test and the voltmeter readings come as less than 12 volts at regular intervals? You can try to jumpstart the car or increase its performance by adding distilled water. If it fails in both cases, you have to change the battery unit.