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How Many Volts is a Car Battery?
A car battery is the power source for an automobile. When a car battery is used, it undergoes a chemical reaction that produces electricity. The voltage of a car battery is measured in volts and can usually be found on the front or back of the battery.
The voltage of a car battery ranges between 12 volts to 48 volts depending on the size, design, and brand of the battery and vehicle. The lower voltage option tends to have less power, durability, and overall lifespan.
If you see a car with a 48-volt battery, it is likely an electric or hybrid vehicle that does not use gas for power. On average, many cars use a battery of around 12 to 15 volts for the different stages of use.
How Many Volts Needed to Start a Car?
Many factors determine how many volts are needed to start a car. The most important factor is the type of battery and how well it is charged because you need about 12.6 volts to get the car started.
This can range a bit depending on the vehicle and the condition of the battery too. We have seen lower voltages get cars started around 12.2 volts, but ultimately your vehicle and battery condition is the deciding factor.
It is much safer to operate your car with a battery that is charged correctly too. This means that it should have no issue getting to 12.6 volts because it will need to go even higher for specific performance levels on the road too.
Once the car is running, the alternator will add power to the battery and get the voltage closer to 13.7 or higher. It is not uncommon to see the battery get above 14 and closer to 14.7 volts too depending on the battery type.
How Many Volts Does a Car Battery Have When The Car Is Off?
Because the battery is still needed, the car being off does not change the number of volts the battery has. If your battery is usable and charged correctly, it should still give a reading between 12.2 to 12.6 volts on average when the car is off.
This is because the battery's alternator along with the engine of the vehicle provides power to the car's electrical system while the engine is off. The battery does not lose any volts because the car is off.
The drain current of electricity from the battery is extremely low when the car is off. This means the effect is minor and there is hardly any influence on the total volts still left inside the car battery.
How Many Volts Indicates The Car Battery Is Dead?
The car battery is dead when it cannot start the engine. This means that the total volts left in the battery are too low to provide enough power to turn on or run your vehicle, making the battery dead and unusable.
You will see a battery with around 11.75 volts or lower be considered dead. This is simply too low and it will be unable to get your vehicle started. If the battery can’t turn the car on, it is a dead battery and needs a charge or replacement.
Once you charge the battery, it can get enough power to turn on the vehicle but this does not mean the battery is still good. It will see a spike in volts and once the vehicle turns on the voltage will drop quickly.
If you notice this, it is a good indication that you are using a dead battery that needs to be replaced. You want to see a voltage spike from your battery when the car begins running, this indicates a good battery.
How Should You Test Your Car Battery Voltage?
It is important to know how to test your car battery voltage as it can save you a lot of trouble. Car batteries are prone to failure and they can fail without any warning, putting you in a difficult situation.
This is why you need to understand the different ways you can test your car battery voltage too. By knowing the voltage, you can identify the problem extremely fast to understand why your battery is failing.
Testing the battery voltage with a voltmeter is one of the simplest ways to know if it needs to be replaced. It is also the most reliable way to know if there is a problem with the battery, but you need the proper tool.
You can start by turning off the engine and ignition and getting the voltmeter ready. The meter can be set to test in DC or DCV ranges to indicate the proper reading method for this test.
Once the settings are complete, you can locate the battery and remove the positive and negative covers. Touch the voltmeter to the proper red and black areas on the battery to get a reading.
It should indicate a voltage reading quickly. We have listed a voltage battery chart below for any 12-volt car battery so you can understand what to look for.
Engine Cranking Method
The engine cranking method is a way to test the car battery voltage. This is done by turning the ignition key on to start the engine with the voltmeter connected.
When this is done, a crank occurs and it gives you a reading to indicate the shape of the battery. If you see a reading below 9.6 volts, the battery will not retain a charge and needs to be replaced.
When Should You Change Your Car Battery?
Car batteries are an important part of your vehicle. They provide power to the lights, ignition system, and other electrical components. You cannot run your car without a reliable car battery.
The battery is a rechargeable device that stores electricity to power the vehicle's engine when needed. The average lifespan of a car battery is 3-5 years, with some lasting longer if used less frequently.
The first sign that your battery needs replacement is when it doesn't start the engine on cold mornings or takes longer than usual for it to start up during hot afternoons. You should test the voltage of the battery regularly too.
If you notice this symptom, we recommend having your battery tested at an auto parts store near you or by a certified mechanic before buying a new one.
12 Volt Car Battery Chart
This 12 Volt Car Battery Chart can be used to learn the different levels of charge on your 12-volt battery for your car. It indicates what each reading means when you test your battery so you know what needs to be done.
For example, if you see that your battery is low on charge you know that it should be taken care of before turning your car off again. If the reading is extremely low, you know that it might be time for a full replacement instead.
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About The Author
I've spent many years selling cars, working with auto detailers, mechanics, dealership service teams, quoting and researching car insurance, modding my own cars, and much more.Read More About Charles Redding