Car Batteries

How Many Volts Is A Car Battery?

Mike Cross
Updated May 19, 2023
How Many Volts Is A Car Battery

So you may be wondering how many volts is a car battery. This question could come up to you for multiple reasons. One could just be that you want to learn about your car. Another thought is maybe your car won't start, and you think it is the battery.

Well, after reading this article you will learn the proper amount of voltage that should be in a car battery. The answer may surprise you.

Car Battery Voltage

A car battery is 12 volts, but this is misleading. This is because a car batteries voltage changes depending on if the car is on and off and how much draw is being put on the battery.

This means that while the vehicle is on a good battery will read higher than twelve volts. You might be thinking though that with the car off a good battery will read twelve volts then, this isn't the case.

A good battery, at rest with the car off, should read between 12.6-12.9 volts when fully charged. This is because the battery is made up of cells usually. In a standard car battery, there are six cells, and they are connected in order.

This causes the voltage of each cell to add up. Some of the cells may have more than two volts while others have less. As long as it reads at around 12.6 volts though it means it is fully charged.

As the battery ages though the cells cannot stay charged as long or to the maximum. This is similar to a phone battery or any other type of rechargeable battery. For a phone, you may know how when it gets older it doesn't stay charged as long. Well, a car battery works the same way.

As time goes on and the battery gets older, the cells get weaker. If your battery is a few years old, then it might only read out at the 12.2volt range or about eighty percent charged.

How Many Volts Is A Car Battery
How Many Volts Is A Car Battery

What Voltage Is Too Low?

This probably leans to you wondering what voltage is too low then. Well, once the reading of the stored energy gets in the 10.6-volt range it is starting become too little.

You can charge your battery back up, but it might not hold that charge for long. If the battery begins growing too weak and not holding a charge, this is when you get issues with your car not starting.

Usually, a car battery does not discharge all the way to 0 before it is no good any longer. Once it is down to about 8 volts on a normal, it is time to get a new battery.

Most batteries have dates on them of how long they are expected to last. The good thing about a car battery is they last for 5-10 years and some longer, but the bad thing is they might be getting weak without you knowing it.

How To Check Voltage

How to check voltage?
How to check voltage?

Since they can start to weaken without you knowing, it is a good idea to check the voltage on occasion. You can try to check it maybe once a year when you are doing one of your oil changes.

This way you can stay on top of it and know your battery life. There are a few things you can do to test your battery and a few ways to check it.

The typical way for people at home to check their car is to use an automotive multimeter. All you do is connect each end of the probe to the connectors on the battery.

You then turn the meter on, and it will give you a readout. This is a simple method and gives you a basic idea of your batteries life, but it doesn't give you a whole lot of information.

The other way to check your battery life is to use a battery load tester. You connect one in the same way and then rev the engine steady for 15-30 seconds. It will help you recharge your batery in the safest way

The tester does a reading on your battery and can tell you how much volts it is holding and how well the alternator is working. It has a known resistance built into it, when you test the battery the tester puts it under 'load' to determine the anticipated amount of remaining life.

If you want this type of check done, you can go to most auto parts shops, and they will do it for you.

How Many Volts When Under Load

So I have let you know the typical resting voltage of your car battery and how to check the voltage, but we still have talked about how many volts are in the car battery when the car is running.

Generally, with the car going and the alternator charging the battery, it can reach 13.7-14.7 volts. This means there is a lot more voltage in the battery then is what is being advertised on it.


Now you know how many volts are in a properly charged battery. You also know a bit more how a car battery works and why it has a higher voltage than the advertised twelve.

You even know how to check your car's battery in a primary way so you can stay on top of it and try to prevent the problem of having a dead car battery.

Mike Cross
Life is too short to drive with stock audio

Leave a Reply

Your email address will not be published. Required fields are marked *

linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram