April 24, 2025 / henry

A Quick Guide: How to Test a Car Battery

Many times it happens that the car doesn’t get started in one go, or doesn’t start at all. First thought a person would get is that there may be a major engine problem due to which the car has stopped working. Sometimes even wondering whether a used engine swap is the only option. That’s not the case always. Sometime the issue may be as simple as a discharged battery. A simple guide for How to test a car battery can be very useful in such cases.

This can be managed quite easily and without any professional help. Checking a cars battery may as simple as switching on a light. It’s not that all of the electrical components of a vehicle is powered by it, but the spark that starts the ignition is also generated by the charge provided by the battery. So it automatically becomes important to have a healthy battery.

This guide is for beginners and experienced owners as well, who want to know more about such issues and want to resolve them on their own.

Car Battery Issues: Cause, Symptoms and fixes

Battery is a vital part of the vehicle which handles all electrical aspects of it. To fix any type of battery issue, first a person should know how one battery issue differs from another. That is why this guide is broken down in three parts:

Causes of battery Issues
Symptoms of failing battery
How to fix battery issue

Causes of Battery Issues

Charging System Issue

If the alternator of the vehicle is not working right, then it won’t charge the battery while the vehicle is running. Keep an eye on the alternators health.

Old Age

Most car battery life is in between 3-5 years. After this they eventually worn out and hold less and less charge.

Corrosion

With time and age the terminals of battery can get corroded, which will hinder the transfer of charge.

Drainage

A battery gets drained because of many reasons some of them are;

extreme weather can evaporate the fluids inside the batter
Faulty wiring can also drain the battery, by keeping a light or any other car part on even when the vehicle is off.

Symptoms of a Failing battery

Slow Engine Crank

If the engine takes time to start or sounds more sluggish than usual, it’s a symptom of failing battery.

Warning Light

Many vehicles have warning light on the dashboard to indicate a low battery or any other issue related to charging system. Do not ignore it.

Dim Lights or Electrical Glitches

If Headlights or any other light is dim or flickering more than usual, it means the battery is struggling.

How to Fix Car Battery Issue

When removing a car battery from the vehicle to resolve any of the issue, first follow these steps:

Remove negative terminal first
Remove positive terminal second

By doing this the risk of short-circuiting will be minimized. It should be kept in mind that the terminals do not get in touch with another metal wrench or something when the terminals are connected.

Clean the Terminals

Corroded terminals can be cleaned with a mix of baking soda and water. Due to this flow of electricity will become normal and the battery will be charged efficiently.

Check the connection

Tighten the cables connected to the battery. Lose cables can cause all sorts of problem.

Replace

If the battery is too old, simply replace it with a new one. There is no alternative to it. When installing a battery always follow these steps:

Connect the positive terminal first
Connect the negative terminal second

This will prevent the accidental grounding and shorting as well.

Test The Battery

Use a multimeter to test the battery, a multimetre will also help you identify any type of parasitic drainage happening in your vehicle.

Step 1: Set the Multimeter to DC Voltage

Turn the dial to DCV (normally marked as “V”)
Set the range to 20V. if not auto-ranging

Step 2: Connect the Probes

Black probe goes into the COM port
Red probe goes into the V mA port (or anything marked for voltage)

Step 3:Touch the Battery Terminals

Place the black (negative) probe on the negative battery terminal
Place the red (positive) probe on the positive battery terminal

Step 4:Reading the Voltage

Below 11.8V = dead battery
12.2 or lower = low charge
12.2V – 12.5V = partially charged
12.6V – higher = fully charged

Fix underlying Issues

For instance if the alternator of the vehicle is not working properly, changing the battery will not be affective in the long run.

FAQ’s

Q.1 why should I test my car battery?

Testing your car battery will keep you ahead of any minor or major problem you can face. Because a faulty battery can leave you stranded in a problematic place or it can cause annoying electrical glitches.

Q.2 how to test a car battery at home?

You can use a multimeter at home with ease. No professional help is needed for this.

Q3. How to test a car battery with multimeter?