Car Battery Voltage | How Do Car Batteries Work? | Test Car Battery with a Multimeter

Test Car Battery with a Multimeter

Car Battery Voltage

#1. Introduction

Everything in this world requires power or energy to work. We living things need energy which we get in the form of food, whereas nonliving stuff like cars or electric vehicles requires energy in the form of electricity or battery.

The car battery is one of the primary power sources to run an electric vehicle from one place to another. The electricity which is stored in the battery helps the car to run the engine.

The standard battery that is used in vehicles is about 12 volts. Voltage has an important role in the performance of the car battery. The life span of the car battery is typically about three to 6 years. The driving habits and their exposure affects the life of the storm.

In this article, you will learn about car battery voltage, its importance in the car, how car batteries work, and how we can test our car battery with the help of a multimeter.

#2. Importance of Battery and Voltage in the Car

A car battery is the most important part of the car. Because of Batteries car gets the power to run and helps the car start when you start the vehicle with the key or self-start. All the electric features work because of this battery.

A Car battery provides the electricity necessary for electric components that work on electricity. The battery also converts the chemical energy into electric energy to power your car and provide voltage to start it. Stable the current flow in the car, which keeps the engine running.

In simple language, the battery is the heart of the car, which provides energy to run the vehicle or its electric components. All the electricity to the car is supplied from the battery, so we can say that the battery is the power station of the car. The battery is the cubical box set at one corner of the engine. That cubical box holds the chemical mixture, which is then converted into electricity.

With time features in cars get added and modified; all the new electric features like sunroofs, panoramic sunroofs, power windows, Electric handbrake, and much more work on electricity and other already existing features like wipers, headlight, fog lights, led DRLs also work on electricity all the energy or power provided by the battery of the car that’s why the battery is the heart of the vehicle.

The flow of electricity the battery holds in that box is nothing but voltage. Nowadays, in new generation cars, the 12-volt battery is used.

Voltage has an important role in the performance of the battery. A Car battery converts the chemical energy into electric energy and provides power or energy to start the car. That’s why an in-car battery is the most critical device, or we can say that batteries are the heart of a vehicle that supplies power to every electric component.

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How Do Car Batteries Work?

How Do Car Batteries Work

The main job of the car battery is to provide the electricity necessary to power all the car’s electrical components. As you notice, your car didn’t start without a battery.

A chemical reaction in your car causes the car to run. Our car battery converts the chemical energy of the vehicle into electrical energy, which helps to power your car.

Car batteries provide the energy necessary to start the car’s engine and stabilize the current supply (Voltage) to run the machine.

A car battery is a type of device which converts chemical energy into electric energy. The cell holds the chemical energy and then converts it into electric energy on demand.

Nowadays, most cars use the chemical energy of lead acid. Every cell contains two different types of plates, one made up of lead and another made up of lead dioxide.

Plates are flooded in sulphuric acid, which reacts as a catalyst and makes chemical reactions between them. Because of this reaction, electrons produce and generate electricity. This electricity, after the response, flows from the battery to the electric components of the car to the car engines. This engine cycle recharges your engines as you run your car’s engine.

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Test Car Battery with a Multimeter

#1. About Multimeter

A multimeter is a device used to measure the circuit’s electric current, voltage, and resistance—professionals who know how to use a multimeter.

They attach the two leads to different parts of an electric system to check the rate or level of the voltage. We use this to review the voltage of the battery of the car.

#2. Measure with Multimeter

When you measure with your multimeter, it will calculate the DC voltage shown by a solid line and dashed line above V, set it to 20 means it will measure the volts between the range of 0-20.

Set the red probe to( + ) terminal and the black probe to (-). Suppose you get minus (-) in reading in front of it. It is the wrong way.

Check whether the reading is lower than 12.6 or not.

The current supply of a regular car should be 12.6 volts. Always test/check your car battery if your vehicle does not start for at least 2 to 3 days to know the voltage rate in the rest position. It is called the resting voltage.

If you drive a car and then check the voltage, it will give you a higher reading than that of when the vehicle is in rest position(resting voltage). To check the accurate voltage, leave the car overnight and test it the following day.

The rate of resting voltage should not be lower than 12.6 V. A battery with a reading of only 12.2V is 50% charged and discharges below 12V.

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How Much Voltage Is Needed to Start the Car’s Engine?

If the voltage of the car is lower than 11.8 V, it is challenging to start the car engine, and when the voltage is lower than 10.8 V, it is impossible to start the car’s engine and consider that your battery is dead and needs replacement.

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Car Battery Voltage Range

The voltage range of the car battery is about 12.6 to 14.4. When the car’s engine is off, the car battery voltage is around 12.6 V. This voltage is called the resting voltage.

When the engine is on, the battery’s voltage is about 13.5 to 14.5 V.

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How Should I Identify Whether My Battery Is Too Old?

Nowadays, cars have more electric components than Mechanical. Most of the features in cars work on electricity. For example, electric seat, tailgate, electric handle, power window, navigation, power sunroof, stereos, sensors, auto headlamps, anti-lock system, traction control, ADAs, etc., makes it hard for the battery of the car to keep working.

After a time, every battery stops at the point where it can’t start the car. This happens because of the leaks and corrosion which sets on the connection.

The right time to change your car battery is before it dies. So How can we identify whether our car battery is getting old?

There are many ways to identify whether the car battery is getting old. If you have a brand new car, the age of the battery is the same as the time passed since you took the car’s delivery.

The right time for battery replacement is while the car engine noise is like it is struggling to start.If you notice something like this, check the car’s battery by turning on its headlamps while the engine is off. If the throw of the headlight is dim, then there is a possibility that the battery is going to die.

There are several Conditions when a car’s battery fails because the car stands in one position for a long time and when the surrounding temperature is low (cold temperature). But it can’t affect the battery.

A quick self-start can reset the battery and bring it back to run. But in some cases, if the battery is too old and in a weak condition, a quick self-start can start the car for a moment, but after some time, the car’s battery will again fail.

You must check your car’s battery after the interval every six months. Test your car battery after every six months. A quick voltage reading by multimeter will let you know whether your battery is strong and runs smoothly or needs service or replacement.

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Symptoms of Low Car Battery Levels

#1. A Lousy Throw of Headlamps

If a car’s battery is going to die, it can’t provide sufficient electricity for the vehicle. This is the typical sign that the battery is getting weak and needs replacement.

#2. Problems in Ignition

When the car is ignited, the battery sends an electric current to the starter solenoid, which works for ignition. A weak battery can’t send that amount of current to the starter solenoid, and the problems come in the ignition system, and a type of clicking sound comes when you turn the key to start the car.

The problem in the ignition is caused by sparking in the plugs, sparking in plug wires, or faulty wires failing the ignition coil. Always remember that mechanical or electrical issues may cause car engine problems, such as using dead batteries and difficulty starting solenoid.

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How to Find Dead Cells in a Car Battery?

The car battery contains six separate cells, and every cell has 2.1 V power. If any of these cells are dead, In such a case, the battery can’t work correctly. Once any car battery cell is over, the battery needs replacement.

After every six months, check the specific gravity of electrolyte fluid to test the car battery for dead cells. If the specific gravity is low in a cell compared to another cell, it means the cell with low specific gravity is dead.

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When Fully Charged, How Many Volts Should a Car Battery Have?

Nowadays, modern vehicles contain a 12-volt battery. Every cell has 2.1 volts of power when it gets fully charged, so when the engine is not running, a car is fully set at 12.4 for 12.6 volts. A 12-volt car battery has six sales.

To charge the battery of a car’s engine, you need to generate about 1000 RPM. At high speed, car engines affect more RPM, so the vehicle’s battery recharges faster than at a low rate. Most vehicles need 30 to 40 minutes to recharge the car’s battery.

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When Does the Battery Need to Be Replaced? How Do You Identify It?

If you are maintaining your car battery properly, but it doesn’t matter one day, it also needs to be replaced. Some cases tell you that your battery is dying if your battery is giving a problem while starting the car or your battery is struggling while startup your car’s engine. It’s the right time to replace the car’s battery.

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How to Visually Inspect the Battery Case and Cables?

  • Check whether the size of the battery is proper or not for the type of vehicle.
  • Check whether the surface of the battery is free of dust and moisture.
  • Check connection of the battery to the electric components is corrosion-free.
  • Check the cables of the battery and whether it is set in the proper size.

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Frequently Asked Questions (FAQ)

Car Battery Voltage

With the engine off, the fully charged car battery voltage will measure 12.6 volts. This is known as “resting voltage.” When the engine is running, the battery voltage will typically rise to 13.5 to 14.5 volts. The battery is boosted to these higher levels by the alternator.

Test Car Battery with Multimeter

The first test with your multimeter will measure DC voltage, indicated with a solid line and a dashed line above a letter V. Set the dial to 20, which will allow you to accurately measure between 0-20 Volts.

Normal Car Battery Voltage

When we take a closer look, we see car battery voltage can range anywhere from 12.6 to 14.4. With the engine off, the fully charged car battery voltage will measure 12.6 volts. This is known as “resting voltage.” When the engine is running, the battery voltage will typically rise to 13.5 to 14.5 volts.

Check Car Battery with Multimeter

Checking the battery of a car with a multimeter. Connect the multimeter leads to the car battery terminals. Sequentially perform the following steps to check the car battery voltage when the car is off:

  • Turn on the headlights for 2-3 minutes to remove any surface charge from the battery.
  • Turn the lights off.
  • Set the multimeter to 15-20V (DC voltage).
  • Connect the red probe plug to the multimeter’s VΩmA port and the black probe to the COM port.
  • Connect the multimeter leads to the battery terminals (red probe to the positive pole of the battery and black probe to the negative pole of the battery).
  • Take the reading on the multimeter.

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