How Many Volts is a Car Battery?

The car battery is one of the components that a vehicle can’t do without. The battery provides power to car accessories, ignition to start the engine and other car systems. Therefore having a dead battery is a lot troublesome, which makes it vital that a car owner should know how many volts a car battery is and that keeping it in good condition is a top priority.

Your car battery has to provide the right voltage to enable you to put ON your engine and run your vehicle smoothly. So you have to measure your battery’s voltage at intervals to know if it’s dead or recharged. Cleaning battery corrosion will go a long way in ensuring adequate electrical contact.

How Many Volts is a Car Battery?

A car’s battery is not only the power source needed for the operation of the engine. It also powers other car features when the engine is off or even when your car is locked. Security systems, lights, and multimedia gadgets, for instance. This makes one quite curious to know how many volts is a car battery when fully charged.

how many volts is a car battery when fully charged

A car battery should read a minimum of 12.6 volts, and when your engine is in operation, the battery should record a voltage value within the range of 13.7 – 14.7 volts. This tells you how many volts is a car battery while running. However, it goes a little higher, up to 15 volts, due to the power being received from the alternator. As an alternative, in the absence of a multimeter, you can conduct a test on your vehicle’s electrical system by turning On the engine and headlights.

Typically, your car battery should read close to 15 volts if it’s at optimum functionality, but it still depends on the condition. When your vehicle is up and running, your car battery should read between 13.7 and 14.7 volts. Anything less than that range signifies that the battery is not operating optimally.

A voltage slightly below 13.7 might still keep your system operating effectively, and you may be curious to know how many volts does a car battery need to start. A low-voltage battery probably means your battery isn’t getting the right power from the alternator, or the battery has lasted long enough. You have to change it soon.

Once your battery is aged, the voltage produced begins to depreciate from there on drastically. 12.5 volts signals a 50% efficiency, 12 volts signals 25%, and below 12 volts is considered a complete discharge. It’s also important that you always replace your battery with higher or equal quality, like the Foxwell bt705 car battery or others of its class.

how many volts is a car battery while running

Car Battery Voltage Chart

12 Volt Battery Voltage
Voltage Per Cell
State of Charge


































How Many volts to start a car?

The battery must provide enough voltage to power the starter motor to start a car. The exact number of volts required can vary depending on the make and model of the vehicle. Generally, most cars require around 12 volts to start.

The battery in a car typically has a voltage rating of 12 volts.

However, it is worth noting that this is not a fixed value and can fluctuate depending on various factors such as temperature and state of charge. If the battery is fully charged and in good condition, it will have sufficient voltage to start the car without hiccups.

But at a lower state of charge, the battery voltage is not the highest but still, the car can be started at as low as 40% of charge level with voltage dropped to 9V. But some cars with sophisticated electrical systems will start at not lower than 11V.

To avoid the hassle, car owners should regularly check their battery’s voltage level to ensure normal battery voltage when the car is running to start their vehicle reliably.


At what voltage is a 12v battery dead?

Fully functional batteries are charged within the range of 12.8 – 12.9 volts. A 12 volts battery is considered dead when it gets to 12 volts or below. Some12 volts batteries are designed to have a minimum voltage, and any circuit using that battery identifies that as a mean or minimum voltage.

However, regardless of what the case might be, once the voltage gets to 11 volts, you might need to jump-start your car with a well-charged battery.

Are 12.2 volts enough to start a car?

12.2 volts is sufficient to start your car. Typically, when your battery falls within the range of 12.2 – 12.6, it means that the battery is efficient and can turn On your engine. If the voltage reading is less than 12.2 volts, your battery needs to be checked.

When should I change my battery?

When your car battery is tested to have a low voltage reading, it shows that your battery is drained. That might not necessarily mean the battery is faulty; it could be that any car features have been ON for a long period. For instance, the lights and radio. When several systems are operating all at once, it can also run out of battery.

You can remedy your battery by charging it and using your voltmeter to ensure it’s gauged. If the battery won’t hold a charge, then your battery is bad. You need a replacement.

Can a battery be bad if it reads 12 volts?

If a battery reads 12 volts when it’s neither under load nor your engine isn’t in operation, it can be labeled a bad battery. Your jump starter is the appropriate loaf to determine the output voltage of the battery under load.

But even with a battery, it might still record a low voltage as the starter runs, but it should turn ON your engine quickly.

How many volts should a car battery lose overnight?

Modern vehicles rely a lot more on battery power, unlike older vehicles, and this is due to the incorporation of computer systems in vehicles, and some of these systems work continuously as long as your battery is in place. However, this shouldn’t draw more than 50mA. A good battery shouldn’t have a significant reduction in voltage overnight. If it reduces to about 10 volts, then your battery is either defective or dead.

The minimum voltage your battery should drop overnight is 12.8 volts, but it still depends on conditions like the ambient temperature.

How to test your car battery voltage?

You can determine the voltage reading of your battery; you need to use the voltmeter. It’s a very simple device to operate. All you have to do is connect the positive end of your voltmeter to the positive terminal of your battery and the negative end to the battery’s negative terminal.

Testing your car battery voltage when off isn’t just enough. You also have to test its strength while you start the engine.

You can have someone start the car for you while you properly connect your voltmeter to the battery. The amount of voltage registered by the voltmeter tells the available power to kick off the engine.

What kills a car battery?

To prevent your battery from getting damaged, you have to know what can kill the battery. Conditions that kill the battery are extremely hot and cold weather, battery age, loose battery connections, bad alternator, high parasitic draw, many brief trips, and when you leave appliances On frequently, it can also drain your car battery.

Final Words

Getting the precise answer on how many volts is a car battery can prove quite difficult because a lot of factors influence it. But it would be best if you had an idea of the minimum voltage your battery should have and the conditions that can drastically reduce your battery’s voltage.

Remember, if your battery doesn’t give out a sufficient voltage, your vehicle isn’t going anywhere, so regular maintenance is necessary.

Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

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