We've all been there – you are running late for work, and you jump into your car, turn the ignition and...nothing - your battery is dead. Before you know it, you are waiting around for your breakdown service to show up and half of the day's gone.

However, all of this hassle could be avoided by being aware of how to know if your car battery needs to be replaced. Knowing how to test a car battery can save you a lot of stress and worry, and luckily there is a simple way to carry out this quick and easy task.

Weak Car Battery Symptoms

Do you know how to identify if your car battery is going bad? Here, we look at some of the bad cells in car battery symptoms to look out for in your vehicle.

The signs of a bad car battery include:

  • Problems with backfiring
  • Dimming of the headlights while driving
  • Slow cranking when you try to start up the engine
  • Issues with the car's electrical systems
  • Car clicks or makes a whining sound instead of starting up
  • The engine light may come appear on the dashboard
  • A strange smell like rotten eggs coming from the hood of your car
  • Swelling or bulging of the battery case If your battery is more than three years old, it should also be tested as this is their average lifespan.

Why Should You Test Your Car Battery?

You should regularly test your car battery, even if it's showing no signs of failure as this will reduce the chances of experiencing a breakdown.

Finding out whether your battery requires replacing will help to save you the stress and worry of being stranded on the road as well as the expense of being towed home.

How Many Volts Should Your Car Battery Have?

If your vehicle's battery is fully charged its batteries should measure 12.6 V or higher, with a measurement of between 13.7 V and 14.7 V when the engine is running.

Your headlights will also tell you about how well your battery is charging – if they remain bright and don't change even when you rev the engine, your charging system is probably fine. If they are dim and brighten when you rev the engine, you may have a charging problem.

What is the Easiest Way To Test A Car Battery?

The easiest way to see whether a bad battery is the root cause of your car problem is to test it with a multimeter. This inexpensive and user-friendly piece of equipment will tell you quickly whether your battery is fully charged or not.

How to Check Car Battery Life With Multi-meter

Do you know how to test a car battery with a multimeter? A surprisingly large number of people have no idea how to carry out this quick and easy test, but if you're one of them, our simple guide will help you to perform this procedure.

  • Turn off your ignition.
  • Find your car's battery. Usually it will be under the hood, however, in some cases, it is in unusual locations such as in the trunk, in the wheel well or under the rear seats.
  • Set the multi-meter to 20 V.
  • Remove the positive terminal cover from your battery.
  • Connect the positive lead (which will be red) from your multimeter to the positive terminal on the battery.
  • Connect the negative lead (which will be black) from your multi-meter to the negative terminal on the battery.
  • Turn on your headlights to give the battery a light load to work with.
  • Check the reading on the multi-meter.

Is the reading between 12.4 and 12.7 V? If so, your battery is in good condition.

Is the reading under 12.4 V? You need to charge your battery.

Is the reading under 12.2 V? You need to trickle charge your battery and then re-test. If the reading remains low on retesting, replace the battery.

Is the reading over 12.9 V? Your voltage is too high and you should turn on your high beams as this will remove the excess charge. This is a sign that your alternator is overcharging your battery.​

If your reading is too low, recharge your battery by either using a portable battery charger or by jump starting your vehicle and running it at a speed of over 40 mph for at least 20 minutes.

This test tells you whether your battery has any charge left, but it does not tell you if the battery is failing. A good battery will be able to hold its charge while a bad battery will not.

What Else Should I Check?

While you are checking your vehicle's battery, you should check its terminals for any signs of corrosion or damage and inspect its case for evidence of damage.

You can clean any dirt from the battery terminals and case with a solution of baking soda and water, but remember to wear goggles and rubber gloves for your own safety when you are carrying out this task.

Checking if Your Battery is Good or Bad

Once you have recharged your battery, you can find out if your battery is good or bad by taking it to an auto parts store or garage. They can use a load tester or electronic tester to determine whether or not you need a replacement.

What if the Test Says my Battery is OK, but my Vehicle Still Won't Start?

If the multimeter's reading shows that your car's battery is functioning well, but your car still won't start up, your vehicle must have a different problem. Your starting system may have a fault, and you should arrange for your car to be taken to a garage as soon as possible.


Now you know how to test a car battery and how to know if your car battery needs to be replaced, you can quickly and easily check it at regular intervals throughout the year.

By regularly maintaining and servicing your battery you can prolong your battery's useful life.Save yourself time and money by using a multi-meter, and you'll never be stranded by the roadside again!

What do you think about the article? Still have some questions in your mind? Feel free to comment.​