How to Test A Battery?

How to Test A Battery?

Table of Contents

Introduction

First things first, let’s answer the question “What is a battery?”. It is a device that stores chemical energy and converts it to electricity. Batteries power numerous tools, devices, and machines.

It is useful to understand whether your battery is charged or not. Proper and timely battery testing is essential if you want to know what is wrong with the battery.

It is important to know how much energy there is in your battery and, as a result, how long it is going to work. You don’t want to unexpectedly discover that your battery is dead when you need it the most.

In this article, we will explain what battery types there are and how to test batteries. Are you ready? Let’s start!

Most common types of batteries

There are many battery types, but let’s consider the most common ones.

  • Alkaline batteries are affordable, non-rechargeable batteries that offer consistent performance until they stop working. Then they are disposed of. Alkaline batteries are used in a wide range of products, including flashlights, toys, radios, the list goes on.

Alkaline batteries

  • Lithium batteries are disposable as well but used in consumer devices that require heavy electrical current use. Lithium-ion batteries are rechargeable, they can power various portable devices, including smartphones, power tools, etc.

Lithium batteries

  • NiMH batteries are rechargeable too and suitable for demanding tasks. They are used in things like laptops and other devices. Note that these batteries take more time for charging, compared to Li-ion batteries, for example.

NiMH batteries

  • In vehicles, you can often find sealed lead-acid batteries. These are rechargeable batteries that are designed for long-term use.

sealed lead-acid batteries

To know for sure whether you can recharge your battery or not, read the information provided by the manufacturer (on the battery or on the package).

How to test a battery using a multimeter?

It doesn’t matter what battery type you have, testing it is not rocket science. For this purpose, you can use a battery tester, a voltmeter, or a multimeter. How to test a battery with a multimeter? Let’s figure it out.

How to test a lithium or alkaline battery?

Things you will need:

  • a battery (lithium or alkaline)
  • a multimeter

1. Identify the positive & negative terminals on the battery.

How to test a lithium or alkaline battery

On AA, AAA, C, D batteries, the positive terminal has a protrusion, whereas the negative one is flat.

If you have a 9V battery, the positive terminal is a smaller, rounded one. The terminal that is larger and has a hexagonal shape is negative.

For lithium batteries, as there are different shapes, pay attention to the markings that show whether the terminal is positive or negative.

2. Select the DC mode on your multimeter.

How to test a lithium or alkaline battery

You can use a multimeter as a voltmeter. The DC mode is indicated by the “V” symbol with a straight line above it. If your device requires to select a level, set your meter to 20V.

3. Hold the positive & negative leads of your multimeter to the positive & negative terminals of the battery.

How to test a lithium or alkaline battery

Note that the red lead is positive. Hold it to the positive battery terminal. The other lead should touch the negative terminal of the battery. For correct readings, do not mix up the leads.

4. Get the reading holding the leads.

How to test a lithium or alkaline battery

Wait for a few seconds and the reading will appear on the display. A fully-charged AA, AAA, C, or D battery has a charge of 1.5V. A 9V battery has 9 volts. If, for example, your meter shows the reading that is at least 1V below the charge that should be, it is recommended to replace the battery. If the battery is rechargeable - charge it. For lithium ion batteries, the charge can vary. It is better to check the manufacturer’s information.

5. Do a load test on your alkaline battery.

How to test a lithium or alkaline battery

With the help of a load test, you can measure the power of you battery when it is in use. Set the voltage dial to 1.5V for your AA, AAA, C, or D battery. If you need to test a 9V battery, then set the voltage dial to 9V.

The red probe of your multimeter should be held to the positive battery terminal, and the black one - to the negative terminal.

For a fully-charged 1.5V battery, the reading should be 4 milliamps, for a fresh 9V battery - there will be 25 milliamps on the display. In case you got readings below the above-mentioned values, your batteries are dead (or almost dead).

How to test a car battery?

It is recommended to test your car battery on a regular basis.

Follow the steps below to do it:

1. Turn your car off & open its hood.

How to test a car battery

Thus you will prepare the battery for testing. To locate the battery, you need to look for a black rectangular box that is marked with the red (positive) and black (negative) terminals.

2. Use a multimeter to check your car battery.

How to test a car battery

The process is similar to testing a regular AA battery.

First, you need to set your meter to the DC mode. Look for “V” with a straight line above it. The end of the black probe should be placed on the negative terminal. Place the end of the red probe on the positive terminal. Now, look at the display.

Your car battery is in good condition if the reading is at (or above) 12.45V. If the reading is below this value, it is better to replace the battery.

Conclusion

Hopefully, after reading this article, you understand how to test a battery using a multimeter. You can also learn more information about how to use multimeters. With these devices, it is possible to measure not only voltage, but also current, resistance, etc. To test a battery, you can use other devices, for example, a voltage tester. Check out our article “How To Use a Voltage Tester?” if you want to know more about it. In addition, on our website, you can read about battery testers. Choose from best-in-class devices on Mega Depot for effective battery testing!

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