How To Test Batteries

There are several ways to test the various types of batteries available and determine how much power is left in them. Among the many battery testers available today, not all are accurate as “capacity” is not always easy to detect. Without accurate battery testing, wastage can occur through the unnecessary replacement of batteries. Understanding how to test batteries can save you loads of frustration, and money.

Battery testing can inform of a variety of things you may need to know about the particular battery, including:

  • How much charge is in the battery
  • If the battery is fully charged
  • ​How long the battery is expected to last
  • ​If the battery meets specifications
  • ​If the battery has deteriorated in performance
  • If the battery is affected by interference/electrical noise
  • If the battery generates interference/electrical noise
  • If the safety devices work

There is even a theory that regular batteries can be tested by simply dropping them!

This test supposedly works for all alkaline batteries, including AA, AAA, C, D and 9 volt batteries. The theory is that a good battery will not bounce, may stand up, and will make a loud noise. A bad battery will bounce several times and usually fall over. The powder-like substance inside the battery turns solid when the battery is discharged, whereas a solid substance is easier to move, which causes these reactions.

Watch the video and see for yourself...​


testing batteries

One way to test standard batteries such as AA and AAA batteries is by using a multimeter.

Essentially, a multimeter is an instrument used to measure electricity and can measure a variety of different things. Most multimeters can measure voltage, electric current and resistance. It is an accepted tool for electronic technicians.

The modern digital multimeters of today have vastly improved from the original needle based analogue meters.

Multimeters generally consist of four main components, being:

  • Buttons (for function selection)
  • Display (for viewing readouts)
  • Dial (for selecting measurement – volts, amps, ohms)
  • Input jacks (to insert test leads)

Test leads plug into the multimeter and act as the conductor from the item being tested to the multimeter.

To test a battery, the two probes are plugged into two ports on the multimeter, and the voltage read-out will then be displayed on the multimeter.

Safety precautions should always be taken when using a multimeter.

Battery Testers/Car Battery Testers

testing batteries

Battery testers come in various forms and are able to test a range of battery types. These include testing:

  • Car batteries
  • Primary batteries
  • ​Rechargeable batteries
  • Disposable batteries
  • Button/coin cells


Battery testers can assist in identifying the status of many types of batteries before they fail, helping to avoid the inconvenience of a failed battery. Essentially, a battery tester will determine the condition of the relevant battery.

Battery testers are generally simple to use, easy to read and able to test most types of batteries on the market.

Testing a car battery is a relatively simple process, although safety precautions need to be adhered to at all times. There are dedicated car battery testers to help determine your car battery life or you can use a multimeter/voltmeter.

Using a dedicated car battery tester, terminals are connected to the car battery and a button pressed which shows the measured car battery voltage.

If using a multimeter, you configure it to measure direct voltage, connect the leads to the battery terminal and read the measurement result on the display screen.

You can use an analogue or digital voltmeter, however digital meters will you a more accurate reading and is easier to read.

There are service centres, such as at auto parts shops, who will test your battery free of charge.

For multiple vehicle types, multi-battery testers are available. Finding a good multi-battery tester can be a little more difficult than finding a regular battery tester. Knowing exactly what you require the battery tester for will help in this search.

Battery Analyser

A digital battery analyser is an accurate device that provides quick results.

Some battery analysers are able to charge a number of batteries simultaneously.

Battery analysers generally test the condition of batteries with very high accuracy, are easy to use and interpret, and fast.

Simple to read displays provide easy to understand information on the condition of the battery and provide advice on action required to be taken in regard to the battery.

Measuring Voltage and Resistance

Multimeters have a common socket, as well as a red-coded socket (V) and an ohm symbol. This advises that it has measured voltage and resistance.

Touching the black probe to the negative (-) point and the red probe to any other location in the circuit will monitor the voltage between them.

Testing voltage is the simplest way to troubleshoot a circuit. By testing voltage you can determine a dead battery, burned-out components, or bad connections.

Measuring resistance of a component requires it to be disconnected from a circuit. The “ohms” value will advise how strongly a component will resist current.

Basic electronic circuits use DC power, however meters can also measure AC, and many have an AC-DC button, while some have AC selections on the dial.

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