How to Change a Car Battery

There may come a day a jump start won’t work and you’ll need to entirely replace a car battery. Read on to learn how to change a car battery by yourself.

Did you know that a car battery replacement can cost you up to $300?

That’s right!

Of course, how much you’ll pay a professional to change your battery still depends on the kind of car you have. Still, the average cost of $118 for professional battery replacement is quite hefty.

If you learn how to change a car battery on your own, you can trim your costs down by at least half. If you already have a toolkit, then you’ll only shell out money for the new battery itself.

Besides, knowing how to replace a car battery can be super helpful if your car breaks down when you least expect it. This way, you can change the battery right away and minimize your downtime.

So, all set and ready to widen your DIY mechanic knowledge? Keep reading, then, to teach yourself the safe and proper way to replace a car battery!

How to Change a Car Battery: Start by Getting the Right Battery Replacement

Car batteries come in different “groups” that classify them based on battery case size. These groups also distinguish batteries by the orientation of their terminals.

It’s important you know what your old battery’s group size is or you might end up with a new one that won’t fit in your car. Whether you buy the new battery online or at an auto parts shop, you’ll have to provide this piece of info.

You can find this information under the specs section of your owner’s manual. Look for a two-digit number followed by a series of letters. For instance, top terminal batteries for Nissans and Toyotas may start with “25”, while Fords have a “65”.

If you don’t have the manual anymore, you can look it up online by researching your car’s specific make and model.

Note that some batteries may also have new model names. In this case, you can use a car battery cross reference chart to find out their group size.

Get Your Tools Out

Changing a car battery isn’t exactly rocket science, but you still need a few tools and proper gear. Wrenches and personal protection will help you safely get that new battery in.


Different fastener types and sizes hold batteries and their cables securely in place. To take these nuts and bolts off, you need a crescent wrench, adjustable wrench, or a socket wrench. Most cars use 10mm-size nuts, but some also use 7mm and 8mm, so it’s best to have all three with you.

Your car may also have battery terminals held in place by quick-release clamps. In this case, you won’t need wrenches or pliers to disconnect the cables.

Personal Protective Equipment

Most lead-acid batteries (the kind of batteries used in vehicles) consist of 60% to 80% lead and plastic. They also contain sulfuric acid and electrolytes. It’s the lead, sulfuric acid, and electrolytes that you have to watch out for.

They’re corrosive and toxic, and exposure to them can cause serious health effects. In fact, half of the injuries related to lead-acid batteries are due to acid burns.

Moreover, car batteries can deliver electric shocks when touched with bare hands.

That said, be sure to don a face mask, goggles, and gloves before replacing a car battery. Things will be greasy, so you’ll also want to wear old, long-sleeved clothing. All these can help protect you from burns and electric shocks.

Pop the Hood and Locate the Old Battery

Park your car on a smooth, level surface and engage the parking brake. Take the keys out of the ignition to be sure that no power flows into the battery.

Next, pop the hood and secure it with a rod. This will help keep the hood from slipping and possibly crashing onto you.

Now, look for the battery, which is likely in a corner near your front bumper or the windshield. It’s the rectangular box that has two cables connected to it.

If you can’t find it, and your car is of a newer model year, its battery may be hiding under a plastic panel. You may have to unscrew this cover first to reveal the battery underneath.

Some cars may have the battery installed in the trunk. 

Remove the Negative Cable First

Most battery cables are color-coded, and black is usually used for negative cables. There should be a minus sign (-) right beside the negative cable. Make sure that you disconnect this first, otherwise, the battery can short.

Unfasten the nuts using one of your wrenches. Use another one to hold down the bolt head in place as you loosen the nut. Once it’s free, carefully slide the cable off the battery terminal.

Only after finishing these steps should you remove the red cable, which is the positive one. Do the same steps to loosen the nuts and bolts holding the “+” cable in place.

Take the Old Battery Out

Check the bracket that holds the battery in place to determine the types of connectors it uses. You may either need a crescent or a socket wrench to remove the nuts and bolts.

Once you’ve unfastened the bracket from the battery, be ready for some heavy lifting. Standard car batteries can weigh anywhere from 40 to 60 pounds. You might need an extra pair of hands to help you lift the battery out of your car.

Install the New Car Battery

Now that you’ve removed the old battery, follow these steps on how to install the new one.

Slide the New Battery in Its Seat

If your new battery came with color-coded plastic covers on the terminal posts, don’t take them out yet. This will help you distinguish the negative from the positive battery post.

After sliding the new battery in its seat, refasten the bracket by screwing back its nuts and bolts. Then, give it a nudge — it shouldn’t budge or wiggle. 

Connect the Positive Cable First

For the new car battery installation, you need to connect the positive cable first. At this point, you can remove the plastic post cover on the positive terminal post.

Spray some corrosion protection on the post first before sliding the cable back on it. Then, secure the cable using the same nuts and bolts that you removed from the old battery.

Follow the same steps when attaching the negative terminal to the negative post.

Refasten Any Other Plate or Panel You Removed

If you removed any battery plate or panel, now’s the time to secure it back in place. Don’t skip this step, as these covers help reduce battery movement when you drive over rough roads.

Close the Hood and Try Starting Your Engine

Don’t forget to remove all the tools, rags, and debris (like the plastic terminal covers) from under the hood.

Once it’s all clear, close the hood cover and put your keys in the ignition. Start your car to check if your DIY battery replacement is a success.

Time to Celebrate!

So long as you followed everything in this guide on how to change a car battery, then your ride should start right up. You should be able to rev the engine and you shouldn’t hear it coughing or sputtering.

If this is the case, then congratulations, as you’ve successfully changed your car battery! You won’t have to repeat these steps until after 30 months, or even longer if you don’t park your car under the sun’s heat.

Ready for more DIY car maintenance and repair guides like this? Then be sure to get this site saved on your bookmarks list so you can keep coming back for more how-tos!

~ by velofinds on October 8, 2019.

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