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Learn How to Change a Car Battery in a Few Simple Steps

Dan Ferrell writes about DIY car maintenance and repair. He has certifications in Automation, Control Technology, and Technical Writing.

Learn How to Change a Car Battery

You can learn how to change a car battery using a simple process. The most important thing is to know how to handle the battery and the battery terminals safely. Even more, changing your own car battery will help you become more familiar with your battery electrical terminals and feel more confident when the time comes to getting rid of terminal corrosion and servicing the battery. This will help to keep your ignition and starting systems working properly.

For this task, you'll only need a few common tools and some materials. Depending on your particular vehicle model, you might need a couple of special tools as well to make sure that everything goes back in place as it should. Once you have the necessary items, the procedure will take you about an hour or less to complete.

What You Need:

  • Car owner's manual
  • Memory saver or 9V battery with jumper wires, if necessary
  • Rag or plastic sheet
  • Goggles
  • Acid resistant gloves
  • Standard screwdriver
  • Six-point wrench set
  • Battery cable puller, if necessary
  • Warm water and baking soda solution, if necessary
  • Soft brush, if necessary
  • Battery post cleaning tool
  • Treated felt washers
  • Petroleum jelly
  • Distilled water

Changing a Car Battery

1. Locate your car battery. Most vehicles store the battery under the hood,
behind the headlight on the driver’s side. Other models carry the battery
under the fender, a seat, or even inside the trunk or luggage compartment.
Consult your car owner’s manual if you need some help.

A couple of things to keep in mind:

  • After disconnecting the battery, you may need a code to reactivate your stereo equipment. Consult your car owner's manual, if necessary.
  • Disconnecting the battery may erase the information stored in your car computer's memory. So the computer will need some engine start-and-shut-off cycles to relearn its driving strategy.

To preserve the computer memory, you have two main options: You can use
a computer memory saver or a 9V battery and a couple of jumper wires. Before
you connect any of these devices, make sure to turn off all your car

When using a memory saver, follow the manufacturer instructions. If you want to
use a 9V battery, get a couple of jumper wires to connect the small battery to
your battery cables. To connect the jumper wires to the battery, you can buy
a 9V battery connector at your local electronic store. Keep in mind that you
need to respect polarity when connecting the jumper wires.

2. Lift and secure the hood open. Cover the fender and front of the
vehicle--around the battery--with a rag or plastic sheet. This will protect
the paint on your vehicle body from car battery acid and keep you from
accidentally shorting the battery as you disconnect it.

3. Put on your safety glasses and acid resistant gloves. Remove the
battery heat shield, if it has one, and set it aside along with its
mounting screws so you do not lose them. You may need a large, standard
screwdriver or wrench for this.

4. Loosen the bolt securing the battery negative (black) cable to the battery
post. To prevent rounding off the nut that holds the bolt to the cable
terminal, use a six-point wrench of the right size to loosen the nut while
holding the bolt's head in position with another wrench. If your battery has
side terminals, you will only need one wrench.

As you remove the battery cables, don't touch the positive and negative posts
at the same time with a wrench--or similar metal tool--or you'll create an
electrical short circuit that may damage sensitive electronic equipment in your
car. Also, keep in mind that batteries produce hydrogen, an invisible and
highly flammable gas. So a little spark may cause your battery to explode. By
removing the negative cable first, you reduce the chances of producing a spark
as you disconnect your car battery.

5. Once you've loosened the grip of the cable terminal on the battery post,
carefully pull the terminal off the post. If the terminal seems stuck,
slightly pry it open with a flat-head screwdriver and try again. Or better
yet, use a battery cable puller.

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Car Computer Memory Saver

6. Secure the disconnected negative cable away from the battery post and
proceed to disconnect the positive terminal following the same procedure.

7. A hold down clamp secures the battery to the bottom tray. Loosen and remove
the screw on the hold down mechanism and set it aside.

8. Lift the car battery using the lifting strap attached to the battery, or
grab the battery with your gloved hands and lift it out of the engine

9. Thoroughly clean the battery tray of debris and battery acid using
a solution of warm water and baking soda to neutralize any acid residues
(use 8 ounces of water per tablespoon of baking soda). Apply the solution
with a soft brush and wipe the tray clean with old rags. You can also use
this solution along with a battery post cleaning tool to remove acid form
cable terminals, if necessary.

10. If you're reinstalling the same battery or a used one, thoroughly
clean the battery case, including the top cover and posts. Use the
same baking soda and warm water solution. Apply it with the soft
brush. And don't let the solution seep under the filler caps. Then
check the electrolyte level. The level should reach the bottom of the
filler rings. Top off the electrolyte with distilled water, if

11. Clean the battery terminals, using the baking soda and warm water
solution and a battery post cleaning tool, if necessary. Avoid using
a knife to remove corrosion from the terminals. You may end up
removing too much metal from the terminal and ruin it.

12. Install the new battery using the same procedure in the reverse order.
Before connecting the battery cables, you may want to install treated
felt washers on each battery post and apply a layer of petroleum jelly
to the cable terminals after connecting the terminals. This not only
inhibits corrosion buildup, but ensures that electrical and electronic
circuits have the proper voltage as you crank up the engine. You can
buy felt washers at any auto parts or department store.

13. Take your old battery to a recycling center for proper disposal, if you
want to get rid of it.

Vehicle Repair Manuals

Once you become familiar with the connections, related components, and how to
handle them safely, you can service the battery with confidence and check electrolyte level, inspect and clean the battery case and connections at regular intervals. This will not only extend your battery service life, but also help your car starting and ignition systems operate

When Installing a Battery

* Check electrolyte level

* Check the condition of the battery case

* Tighten the hold-down mechanism properly

* Remove corrosion from Cables and terminals

* Install a treated felt washer on each post

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

Questions & Answers

Question: Could the person who installed my new car battery also have done something to cause the washer fluid for the windshield to stop coming out of the reservoir?

Answer: Not necessarily. Have an assistant operate the windshield washer pump as you regularly do, but pop the hood open and try to listen for the pump operating. If you can’t hear anything, probably the pump is bad. If you can hear it working and no fluid comes out, check the hoses and nozzles. See if one of them is disconnected, loose, damaged or if the nozzles are clogged.

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