How to Check a 12V Battery with Multimeter- An Automotive Guide

If you're a car owner, at some point you're going to have to check your 12V battery. Maybe it's not holding a charge like it used to, or maybe you just want its condition before winter sets in. Whatever the reason, this automotive guide will show you how to check a 12V battery with multimeter. But before jumping on to the testing guide, there are a few things you must understand.

Tools Required:

  • Digital multimeter
  • Screwdriver
  • Cotton gloves
  • Safety Googles


How to check a 12v battery with multimeter

First, you'll need to gather a few supplies. You'll need a digital multimeter, some jumper cables, and something to clean the battery terminals with (like a toothbrush). If you're looking for a multimeter then i have also made a list of 8 best multimeters for automotive use. Once you have everything, follow these steps:

Step 1:

Clean the battery terminals with your chosen cleaner. This will help ensure that you get an accurate reading.

Step Two:

Attach the multimeter to the battery terminals. Make sure that the red lead is attached to the positive terminal and the black lead is attached to the negative terminal.

Step Three:

Set your multimeter to the "DC volts" setting. If you have an auto-ranging multimeter then rotate the dial to "V" and press the "ac/dc" button for DC Voltage selection.

Step Four:

Note the reading on the multimeter. If it's 12.65 or above, then your battery is in good condition. Anything below 11.8 indicates that your battery needs to be charged.

Step Five:

You can also check battery health with a battery tester. This is a quick and easy way to see if your battery needs to be replaced.

A battery tester will have two probes, one red and one black. Touch the red probe to the positive terminal of your battery and the black probe to the negative terminal. If the light on the tester illuminates, then your battery is good. If the light doesn't come on, then your battery needs to be replaced.

If you want to buy a battery tester then I have also made a list of the 7 best battery testers for you.

Signs that your battery needs to be replaced

There are a few signs that indicate that your battery needs to be replaced, even if the test results say it's still good.

These are just a few of the signs that indicate that your battery needs to be replaced. If you're experiencing any of these issues, then it's time for a new battery.

How to replace a car battery?

If you've determined that your battery needs to be replaced, then follow these steps:

  • Open the hood of your car and locate the battery. It will usually be close to the front of the engine.
  • Disconnect the negative terminal first and then the positive terminal. You can use a wrench or pliers to loosen the terminals.
  • Remove the old battery and clean the area around the battery tray. This will help prevent corrosion.
  • Install the new battery and tighten the terminals. Make sure that they are tight so that they don't come loose while you're driving.
  • Close the hood of your car and you're done!

Tips for keeping your car battery in good condition

There are a few things that you can do to keep your car battery in good condition:

Drive regularly- If you let your car sit for too long, then the battery will lose its charge. Try to drive your car at least once a week, even if it's just around the block.

Keep it clean- Cleanliness is important when it comes to batteries. Make sure to clean the terminals and keep them free of corrosion.

Check the fluid level- Most car batteries are "maintenance-free," but it's still a good idea to check the fluid level every once in a while. If the level is low, then you can add distilled water to bring it back up.

Keep it cool- Heat is the enemy of batteries. Try to keep your battery out of direct sunlight and don't store it in a hot place like the trunk of your car. Always check the radiator fan is on. You can also check radiator fan relay with the help of this guide.

If you follow these tips then you can help extend the life of your car battery.  If you want to check your car battery health then click here.

I hope that this guide was helpful for you. If you have any questions then please leave a comment below and I will try to answer them as best I can. Thanks for reading!

Car Battery FAQs

How often should you test your battery?

It's a good idea to test your battery at least once a year. You can do this at home with a multimeter or take it to a professional to have it tested.

Is it bad to leave your car battery disconnected?

It's not bad to leave your car battery disconnected for a short period of time. However, if you're going to be gone for more than a week, then it's possible that your battery may be damaged or die.

How long does a car battery usually last?

The average lifespan of a car battery is about four to five years. However, this can vary depending on how often you use your car, the climate, and how well you take care of it.

Why is my car battery dying so fast?

There are a few reasons why your car battery might be dying fast:

  • You're not driving regularly- If you let your car sit for too long, then the battery will lose its charge. Try to drive your car at least once a week, even if it's just around the block.
  • It's old- Batteries don't last forever. Even if you take good care of it, eventually it will need to be replaced.
  • It's hot- Heat is the enemy of batteries. Try to keep your battery out of direct sunlight and don't store it in a hot place like the trunk of your car.
  • There's a problem with the alternator- The alternator is what charges the battery while the car is running. If it's not working properly, then the battery will die. I have also made a separate guide on how to check your car alternator. 

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