How to change your car battery | Autoblog Wrenched

Tips from an expert, and tools for doing it properly

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Changing your battery is pretty simple, but you need to do it correctly to prevent dead batteries and potential shorts. We'll teach you how.

Watch all of our Autoblog Wrenched videos for more tips on how to diagnose, fix, and modify cars from professional detailer Larry Kosilla. While you're at it, check out Larry's other car cleaning and maintenance video series Autoblog Details!

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Instructions (Video Transcript):

[00:00:00] Changing your battery is pretty simple, but there are a few things you need to remember to avoid a dead battery and a potential short. Here are the tools you'll need to do it yourself. A new battery, a wrench or socket, screwdriver, gloves, a wire brush, battery lube, baking soda and safety glasses. I'm Larry Kosilla, pro detailer and trainer for the last 15 years. But when it comes to what's under the hood, I'm the student. Follow me as experts teach me how to diagnose, fix and modify cars on AutoBlog's Wrenched.

[00:00:30] As you can tell, I've had this car for a really long time and the battery finally pooped out on me. And I didn't leave the lights on for three days or anything like that. So what could make the battery die? - There's a lot of heat trapped inside your engine bay and your battery has water in it, so if too much water evaporates out of your battery, your battery can die. Other ways your battery can go bad is if you over charge it, you overly discharge it, it's heat or it sees too much vibration. - [Larry] Even if your battery wasn't affected by one of these issues, all batteries have a limited life and eventually will need to be replaced.

[00:01:00] Another common reason for low or no electrical power could be a bad alternator. But if you know the issue resides with your battery, here's how you change it. Step one is to find your manufacturer's suggested battery's CCA or Cold Cranking Amps. Which basically determines the amount of power you have to start your car in most climates. Visit your local auto store and give them the make, model and year of your car so they can match it with the correct CCA. Then double check the part with your car's manual,

[00:01:30] to ensure you are using the proper power and size battery. Then, turn off your car, remove your keys and find your radio code. To remove the battery, start with the negative or ground side first. Generally, this is the black terminal, but check the symbol on the battery to be sure. If you were to start with the positive side, which is generally red, and accidentally touch another piece of metal, you would short the positive to the rest of the car, which is still grounded. To avoid that, we start with the ground first to give ourselves a dead battery as soon as possible.

[00:02:00] Nonetheless, be very careful not to accidentally allow your ratchet to touch both terminals. Sparks will fly, you'll get zapped, and it's obviously not good for the battery. Afterwards, remove the red, or positive side of the battery. There is no need to completely remove the bolt, just get it loose enough to wiggle off the terminal. Now, most batteries have some type of tie down or hold down to secure the battery in place, to avoid it from tipping over on a hard turn or heavy braking situation. Keep in mind you might need to add an extension

[00:02:30] on your ratchet to reach this bolt. When lifting the battery, make sure to keep it straight up and down and grab from the bottom, or use it's handle. Batteries typically weigh about 40 pounds, so make sure you have a good grip and don't blow out your back, or crush your finger. Even more important than that, don't drop it on the paint. The next step, although optional, is to clean out the battery tray of leaves and junk with a vacuum. Not really necessary, but you guys know me, I can't help myself. Now, if you happen to see white powdery stuff on the tray or the hold down piece or even the cable terminals

[00:03:00] themselves, this is usually the result of a sulfuric acid chemical reaction from a leaky battery, and may be the cause of it's failure. You can remove this corrosion with a wire brush, but be careful not to inhale the white powder. Likewise, a mixture of baking soda and water applied with an old toothbrush will neutralize the acid with the base of the baking soda. Whichever method you choose, be sure that the battery terminals and wires are clean, before you install the new battery. In our case, we're replacing the battery all together, so no need to spend time on the old terminals.

[00:03:30] Before installing the new battery, clean the terminals and apply battery lubrication, known as dielectric grease, to help minimize corrosion in the future. Now, place the new battery in the holder and secure it with the tie down bolt. It's extremely important to attach the positive or red terminal first when re-installing the battery for the same reason we discussed when removing the battery. Likewise, the rule of not touching both terminals together still applies, so watch your tool placement. Finally, attach the black terminal

[00:04:00] and tighten down with your ratchet til the clamp or the bolt can no longer be twisted. There is no need to over tighten. Before you close the hood, give the battery a courtesy wiggle just to double check it's secure. Then make sure the car starts. Now, the only thing left to do is reprogram your favorite radio stations. Man, there's nothing worse than that! Well, maybe not as bad as sitting in a parking lot by yourself in the rain, with a dead battery. For more How To Car Repair Videos, visit I'm Larry Kosilla, from As always, thanks for watching. (upbeat music)

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