What Is A Battery Tester?

What Is A Battery Tester?

Last Updated on by Daniel Lawrence

If you’re here, searching for what a battery tester is, then you are at the right guide. battery testers can come in really handy when you need them. Read through to find out what a battery tester is.

What is a Battery Tester?

A battery tester is an electronic device intended for testing the state of an electric battery, going from a simple device for testing the charge actually present in the cells and/or its voltage output, to more comprehensive testing of the battery’s condition, namely it’s capacity for accumulating charge and any possible flaws affecting the battery’s performance and security.

Every battery has a direct current. Battery testers work by applying a load and monitoring the voltage response of the battery. This enables the device to identify how much power is left in the battery.

Ideal for both monitoring and troubleshooting, battery testers are used across a broad spectrum of applications and industries, including:

  • Industrial maintenance
  • Automotive
  • Facility maintenance
  • Electrical
  • Test and measurement
  • DIY and domestic purposes

Simple and easy to use, these devices provide quick, straightforward results and are a staple battery charger accessory for professionals and DIY enthusiasts alike. Battery testers may also be known as voltage meters.

Types of Battery Tester

There are multiple different types of battery tester, each suited to varying battery types and sizes. Some of the most common types are detailed below.

  • Electronic Battery Tester

Electronic and digital battery testers are used to test the remaining capacity of a battery.

Most digital models feature an LCD which presents the result of the battery test in a clear and easy-to-read format. Often displayed in the form of bars or a graph, depending on the particular model, this enables quick reading and analysis of the test results via a user-friendly interface.

  • Domestic Battery Tester

A domestic or household battery tester is normally used for rechargeable cylindrical batteries including AA batteries, AAA batteries, and 9V PP3 batteries.

Common battery chemistries include alkaline, NiCd, and Li-ion. These standard chemistry types cover the majority of everyday household batteries including those outlined above as well as additional battery types such as C batteries and D batteries. A typical domestic battery tester will be suitable for testing a combination of these battery types, if not all of them.

  • Universal Battery Tester

Universal battery testers are suitable for use with batteries in a range of different sizes. Similar to domestic battery testers, they are primarily used for cylindrical batteries.

However, some voltage meters can test a large variety of different-sized batteries, ranging from smaller button cell batteries to larger industrial and automotive batteries.

  • Car Battery Tester

Car battery testers are intended for use with lead-acid batteries. These testers connect to vehicle batteries to provide a clear indication of the battery’s health, condition, and voltage output

Battery testers for automotive applications are important. It is crucial to determine the condition of car batteries as high currents are drawn during start-up. You must ensure that your tester is compatible with lead-acid batteries before use, to ensure safe testing conditions.

How Does a Battery Tester Work?

Since most batteries don’t come with built-in meters to tell you when they are out of power it can be hard to tell when household batteries can be used or should be replaced without testing them first.

Without a battery tester or multimeter, the only way to do this is by popping the battery or batteries into an electronic device and trying to turn it on. This is a time-consuming process, though, and battery testers let you test single batteries quickly and accurately.

Battery testers work by testing the current that comes from a battery. When something conductive is touched to both the positive and negative contacts on the battery, the current is released. Many adventurous individuals test 9 volt batteries, using this principle, by sticking the contacts to their tongue, and anyone who has tried this knows that a charged 9 volt will offer a small jolt.

A battery tester does the same thing, without the pain, by using a conductive medium to measure the charge (amperage) that comes from the battery. Each tester also has a gauge that reflects the level of the charge.

The most rudimentary battery testers, those found on battery packages, use conductive ink that responds to minute temperature changes. If a battery has a charge, the ink heats up as the current passes through it. If the temperature is higher, the battery has more current.

The gauge changes color based upon the temperature. Handheld battery testers and multimeters use resistors to measure the current, and, depending upon the tester, other components to move the gauge, which is usually a pin. As the resistor measures more amperage, the pin moves further on the gauge.

Battery testers only measure current. On many batteries, such as lithium, the results of reading will be inaccurate. This is because the current does not wear down evenly, as it does in an alkaline battery, but takes a significant drop at certain charge levels.

These batteries will read fully charged even if they only have half a charge remaining. Testers also will not tell you if a rechargeable battery can be charged again. To test this, you’ll need to use a battery conditioner or a battery tester that is specially designed for rechargeable batteries.

How do the analog and digital battery testers differ?

There are both analog and digital battery testers available. They are used in similar ways, only the display is slightly different; the digital one using an LCD screen with bars as indicators and the analog using a needle dial.

However, they work slightly differently: analog battery testers measure batteries under load, which means they test the batteries as if they are in use. This gives a more accurate picture of the battery’s remaining life. See below for more information.

Digital battery testers need a battery to function and do not include the resistor, which is what measures the battery under load on an analog tester. Digital battery testers are not as effective as their analog counterparts because of this.

How to Use Battery Testers

It is always recommended to refer to the instruction manual or manufacturer’s guidelines for your particular model. Additionally, before testing a battery, you must ensure that the tester is fully functioning and compatible with the type of battery you are intending to test.

The actual process of using a voltage meter is relatively simple and straightforward. You will need to insert the battery into the tester, ensuring the positive and negative contacts on both the battery and the tester match up correctly. Make sure that the battery is firmly secured in place before you take the reading.

As with any other tool or device, you should take care to protect and maintain your battery tester to help prolong its useable lifespan and minimize the risk of damage. Battery testers should be stored in cool, dry conditions such as within a toolbox.

They are relatively low maintenance pieces of equipment and will usually require just a simple wipe down to keep the screen clean and free from dust and dirt. Remember, do not use a wet cloth as this could damage the device. Instead, use a clean cloth or ideally, specialized electronics cleaning wipes.

How to Take a Voltage Meter Reading

Once the battery is correctly positioned, you should be able to take a voltage meter reading.

Depending on the specific model you have, the output of the test may vary between several different results formats. If your battery tester displays a graph or chart, it should be easy to assess the battery’s remaining capacity.

As a general rule, batteries in the green or pointing towards the higher end of the scale are most likely to be in good working order with a strong remaining capacity. Batteries with results around the middle of the scale may still be suitable for use in some lower-power applications, but close monitoring will be required. Batteries where the indicator points to the lower end of the scale, perhaps in the red section, will have the little remaining capacity and should be changed or recharged, depending on the type of battery.

How to Choose the Best Battery Tester

Various factors will contribute to the purchase of a battery tester. Most importantly, you must ensure that the tester you choose is compatible with the type or types of battery you will be testing. Additional features will largely come down to personal preference and your unique requirements.

Some key factors to keep in mind when looking for the best battery tester include the following:

  • Compatible battery types
  • Price and your budget
  • Brand loyalty
  • Additional features offered

As a result, deciding what is the best battery tester will primarily depend on your own requirements, so it is important to conduct thorough research and ensure the tester you choose meets your needs.


Battery testers are one of the electrical tools that can be used by anyone, as they do not deal with exposed sources or high levels of electricity. Additionally, there are no complicated measurements to interpret – the battery tester will simply tell you whether a battery is worth using or needs to be disposed of/ replaced.