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Replacing the battery is easy, but you need to do it correctly to prevent battery drain and potential short circuits. We will teach you how.

watch all our Auto Blog Wrench Video for more tips on how to diagnose, repair and modify your car from professional groomer Larry Kosilla.While you’re at it, check out Larry’s other car cleaning and maintenance video series Auto Blog Details!

Materials used:

Instructions (video recording):

[00:00:00] Replacing the battery is pretty straightforward, but there are a few things you need to keep in mind to avoid a dead battery and potential short circuit. Here are the tools you need to do it yourself. New batteries, wrench or socket, screwdriver, gloves, wire brush, battery lubricant, baking soda and goggles. I’m Larry Kosilla, a professional detailer and trainer for the past 15 years. But when it comes to what’s under the hood, I’m a student. Follow me as experts teach me how to diagnose, repair, and modify cars on AutoBlog’s wrench.

[00:00:30] As you know, I’ve owned this car for a long time and the battery finally pooped on me. And I haven’t turned on the lights or anything like that for three days. So what made the battery dead? – A lot of heat builds up in the engine compartment and there is water in the battery, so if too much water evaporates from the battery, the battery may drain. Other ways a battery can go bad is by being overcharged, overdischarged, heated or vibrated too much. – [Larry] Even if your battery isn’t affected by one of these issues, all batteries have a limited lifespan and will eventually need to be replaced.

[00:01:00] Another common cause of low or no power can be a damaged alternator. However, if you know the problem is with the battery, here’s how you can replace it. The first step is to find the manufacturer’s recommended battery CCA or cold cranking current. This basically determines the amount of power needed to start the car in most climates. Visit your local auto store and tell them the make, model and year of your car so they can match it to the correct CCA. Then double check the parts with your car manual,

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

[00:02:00] Still, be very careful not to accidentally touch the two terminals with the ratchet. Sparks will fly and you will be electrocuted, which is obviously bad for the battery. Then, remove the red or positive side of the battery. There is no need to remove the bolt completely, just loosen it enough to swing the terminal. Most batteries now have some type of tie-down or securing device to hold the battery in place to avoid tipping over in tight corners or under heavy braking.Keep in mind that you may need to add extensions

[00:02:30] Reach this bolt on your ratchet. When lifting the battery, be sure to hold it straight up and down and grab it from the bottom, or use its handle. Batteries typically weigh around 40 pounds, so make sure you have a good grip and don’t blow your back or squeeze your fingers. More than that, don’t drop it on the paint. The next step, albeit optional, is to vacuum the battery tray of leaves and debris. Not really necessary, but you know me, I can’t help myself.Now if you happen to see a white powdery thing on a tray or fixture or even a cable terminal

[00:03:00] In itself, this is often the result of the sulphuric acid chemistry of the leaking battery, and may be the cause of its failure. You can remove this corrosion with a wire brush, but be careful not to inhale the white powder. Likewise, applying a mixture of baking soda and water with an old toothbrush will neutralize the acid with the baking soda base. Whichever method you choose, make sure the battery terminals and wires are clean before installing a new battery. In our case, we replaced the batteries together, so there was no need to spend time on the old terminal.

[00:03:30] Before installing a new battery, clean the terminals and apply battery grease (called dielectric grease) to help minimize future corrosion. Now place the new battery in the holder and secure with the captive bolts. It is important to connect the positive or red terminal first when reinstalling the battery for the same reasons we discussed when removing the battery. Again, the rule of not touching both terminals at the same time still applies, so be careful with your tool placement.Finally, attach the black terminal

[00:04:00] And ratchet until the clips or bolts no longer twist. There is no need to over-tighten. Before closing the hood, give the battery a polite wiggle to double-check that it’s safe. Then make sure the car starts. Now, the only thing to do is to reprogram your favorite radio station. Man, it doesn’t get any worse than this! Well, maybe it’s better to sit alone in the parking lot in the rain with a dead battery. For more how-to videos, visit autoblog.com/wrench. I’m Larry Kosilla from AmmoNYC.com. As always, thanks for watching. (happy music)