How to Make a Car Battery Fail Test | Step-by-Step Guide

How to Make a Car Battery Fail Test

Car batteries are its power source, so if they aren’t functioning properly, you will have problems. Since it is so readily overlooked by those who need help understanding its significance, proper battery care, and testing are relatively easy. This article will instruct us on how to make a car battery fail test more effectively.

What exactly is a battery test, and how can I do one?

A battery load test is an example of a battery test that evaluates the amps generated by a charged battery. Battery power is known by the acronym CCA or cold start amps.

How to Make a Car Battery Fail Test

You can determine if your battery can power the starter motor by running a load test. You need a battery load tester to complete the test.

How to Make a Car Battery Fail Test

Use it as follows:

  • Start by fully charging the battery. To guarantee a precise outcome, you must take this action. If you have a battery charger handy, you can use it. Make sure the voltage of the battery matches the voltage shown on the battery label using a voltmeter.
  • Next, ensure your multimeter is configured to measure voltage and is connected to the battery. Charge the battery before the stress test if the measured voltage is less than 10% of the label value.
  • The multimeter must now be unplugged from the battery. Once more, check the battery label to see the rated current. You should see “CCA” with a number after it. This quantity represents cold start amps. To acquire the number for your stress test, divide that number in half. If your CCA is 500, for instance, you would need 250.
  • Make careful you connect the positive terminal of the load tester probes to the positive battery terminal and the negative terminal to the negative battery terminal.
  • A minimum of 15 seconds should be given away from the sensors. Then, read the load tester and contrast it with what you saw in other steps to see whether they match.

Your battery will only generate enough power to start your engine if the reading is between 10% and 15% below the level you estimated. 

How to Make a Car Battery Fail Test

How to Make a Car Battery Fail Test

Overcharging a car battery can result in it failing the test. This involves using an excessively high voltage for an extended time. The battery life may be shortened, and the cells may be damaged. It may also result in battery acid leaks, which could harm the vehicle.

Overcharging a car battery might also make it fail the test. It follows that you need to charge it sufficiently or at all. In addition to shortening battery life, this can harm the battery cells.

Discharging a car battery too thoroughly is another technique to guarantee it won’t pass the test. The battery is thus fully utilized before being recharged. In addition to shortening battery life, this can harm battery cells. Maintaining a constant charge and avoiding overcharging, undercharging, and over-discharging are the best ways to keep your car battery from failing the test.

How to Make a Car Battery Fail Test

Process of Testing a Car Battery

Configure your multimeter.

To test your car battery, you don’t need any expensive equipment. A basic multimeter can tell you a lot about the condition of your automobile battery.

You must initially confirm that the settings are the right ones. Choose 20V DC if you don’t have an auto-ranging multimeter.

Configure your multimeter

Join your multimeter

Before connecting the multimeter:

  • Turn off the ignition.
  • Make careful to turn off all the lights and accessories as well.
  • Connect the red wire to the positive terminal, typically identified by a “+” or a red cap.
  • Connect the black wire to the battery’s negative terminal.
Configure your multimeter

A value greater than 12 volts is required. If it is lower, the battery either has to be charged or is damaged.

Test before proceeding

You can test the battery upon startup if you want further details. This test will enable you to decide whether the battery only requires charging or a replacement.

Configure your multimeter

Make careful to turn off all the lights and accessories once more. You can also disable the ignition or fuel system if you don’t want the engine to start. The engine must be just fired up for this test.

Go to an automobile parts store

There are alternatives if you don’t have a multimeter or must prepare to test your car battery. Many auto parts retailers provide free battery testing.

Configure your multimeter

You can also go to your neighborhood mechanic. However, there is typically some form of diagnostic cost associated with this battery inspection. 

Frequently Asked Questions

Why do batteries lose power?

The acid build-up is a frequent reason for battery failure. A stratified battery’s top half of the cell has low acidity because the electrolyte is concentrated in the bottom of the battery. This effect is akin to when the waitress forgets to deliver a stirring spoon, and sugar settles to the bottom of a cup of coffee.

Why do automobile batteries lose power so rapidly?

Corrosives include battery acid. Although it may seem obvious, corrosion at the connections contributes to car batteries’ constant drain. Investigate what’s happening under the hood. The connectors on the top of the battery, designated as the battery terminals, have positive and negative labels.

How can you check if a car battery is failing?

Apply a load equivalent to 50% of the CCA battery’s rated voltage for 15 seconds using the battery load tester. It is the suggested approach. Using a battery tester, apply a load equal to half the CCA requirements for the automobile for 15 seconds.

Why should the test battery be charged?

If your battery is having difficulties producing electricity, it may have a chemical issue. Maintain your battery regularly to get the most out of it. 


Testing the battery is the best approach to discovering whether this is the issue or if the alternator needs to be repaired, even though it can be challenging to identify the exact nature of an electrical problem in your automobile.

Expert Opinion

You can hire a technician to complete this task if you’re uncomfortable using one or want to avoid investing in one. Hiring a mechanic to complete this task alone will likely cost you far more than purchasing the multimeter. If you own a multimeter, you can at least complete this task as often as necessary.