Find Your Local Walmart Tire Center


How to Change a Car Battery

How to Change a Car Battery

Why pay a mechanic to replace your car battery? These easy-to-follow steps will help you do it yourself and save.

Examine the Battery

Before you buy a new battery, take a good look at the old one. It should list the following numbers on the label:

  • Battery group (the size of the battery)
  • Reserve capacity (how long the battery can run the car if your alternator fails)
  • Cold-cranking amps (how well the battery performs in cold weather)

Just write down these numbers (or check your owner’s-manual if you can’t find them on the battery) and purchase a new battery with the same stats. If you can’t find either, ask your mechanic or automotive center expert which battery is right for your car’s make, model and year.

You may want to consider a battery that’s the same size but has a larger reserve capacity and higher cold-cranking amps if you live in a cold climate. Not sure if you need the extra power? Ask your mechanic or automotive center expert what battery will work best in your region. 

Before You Start

Is your old battery covered in corrosion? Clean it off before you replace it using a mixture of baking soda and water and a brush. Be sure to wear gloves so you don’t touch the corrosion with your bare hands.

Unmount the Old Battery

Using a wrench, loosen and remove the mount that holds the negative battery cable onto the battery. It’s best to wear gloves, and never let the wrench touch any other metal part of the vehicle. The negative cable is connected to the negative terminal of the battery. Look for the minus sign where the cable connects to the battery. Once the negative cable is loosened and removed, do the same thing on the positive side. The positive terminal has a plus sign for easy identification.

Before you take the battery out of your car, note how it’s placed. Then, put the new battery in the car in the same position, with positive and negative terminals facing the proper direction. 

Remove the Battery

Some batteries are held in place by a metal bar or a strip. If so, remove the nuts or bolts that connect the bar to the car frame. Now, you’re ready to pull out the battery.

If you’ve already bought a new battery for the car, you know how heavy they are; use caution when taking out the old battery. Lift it with a smooth pulling motion. 

Install the New Battery

Put the new battery into the car facing in the same direction as the old battery. Hook up the positive terminal first. Don’t touch any other metal part of the car with your wrench as you tighten the connection. Once the positive terminal is connected, hook up the negative terminal, and replace the metal bar or strip holding the battery in place if your car has one.

Start the Car

After you’ve installed the new battery, start your car to make sure the battery works and that you’ve tightened the connections properly. If your car doesn’t start, tighten or reconnect the battery cables. Then, start the car again.


Old batteries should be recycled. If your mechanic doesn’t take car batteries, ask if there is a recycling center nearby that can.

Print Article

Important Walmart Disclaimer: Proper service and repair procedures are vital to the safe, reliable operation of all motor vehicles as well as the personal safety of those performing the repairs as well as those riding in the motor vehicles. Standard safety procedures and precautions (including use of safety goggles and proper tools and equipment) should be followed at all times to eliminate the possibility of personal injury or improper service which could damage the vehicle or compromise its safety. Although this material has been prepared with the intent to provide reliable information, no warranty (express or implied) is made as to its accuracy or completeness. Neither is any liability assumed for loss or damage resulting from reliance on this material.

All content, including but not limited to, recipe and health information provided in In Stores Now, is for educational purposes only. Such content is intended to supplement, not substitute for, the diagnosis, treatment and advice of a medical professional. Such content does not cover all possible side effects of any new or different health program. Consult your medical professional for guidance before changing or undertaking a new diet or exercise program. Advance consultation with your physician is particularly important if you are under eighteen (18) years old, pregnant, nursing, or have health problems.

If you have dietary restrictions and/or allergies, always read the ingredient list carefully for all food products prior to consumption. Allergens and their derivatives can have various names and may be present in some food brands but not others. If the ingredient list is not available on the food product, check with the food manufacturer, or do not consume the product. If you have a food allergy, speak to your physician and/or a registered dietitian for a comprehensive list of foods and their derivatives to avoid prior to using any recipe from Neither the author nor assumes any responsibility for errors, omissions or contrary interpretation of the subject matter herein.

Product information is provided by the supplier or manufacturer of the product and should not be construed as advice. Walmart does not sponsor, recommend or endorse any third party, product, service or information provided on this site.