What To Know Before You Disconnect Your Car's Battery

an old car battery

Make sure to consider the Dangers and the Tasks of the Removal Process

Removing a car battery should be simple. You just have to disconnect the terminals in the right order, unscrew the nuts and bracket that hold the battery to the plate, and you’re all set. Unfortunately, it’s not usually going to be that simple, and you will need to keep in mind a few important safety considerations before you even start. The dangers of removing your old battery, coupled with the risks presented by corroded terminals will fully warrant the highest safety measures. Find the best car battery for your vehicle. 

Removing Your Old Battery Safely

The question is how to remove car battery connections and nuts with ease, without having to deal with the risk of a short circuit or a powerful electric arc. The answer starts with understanding the risks. The battery is designed to release a high amount of electric current in a very short amount of time. This means that it’s actually possible to have cases where you accidentally cause a short circuit with a piece of jewelry, and have it melt onto your hand. Another possible risk is that the corrosive, acidic leaks from your battery might touch your skin and cause chemical burns. This issue can be avoided through proper care and wearing the appropriate safety gear.

Advance Auto Parts stores offer free battery testing and installation*. 

How to Prepare for the Battery Removal Process

When it comes to knowing the details of removing your battery, it is essential to have good knowledge of all the preparation tasks. One of the first steps to take is to use zip ties to keep the battery cables in their proper place. Other restraints can be used as well, but you have to make sure the cables won’t touch by mistake and create sparks that could be potentially flammable. Along the same line, consider covering the positive cable end with a shop towel, preventing it from creating any metal-to-metal connections with the negative cable or any other metal, grounded components.

removing the negative battery cable

Why You Have to Remove the Negative Cable First

If you ask experts what is the most important detail you should remember about how to remove car battery parts, they’ll tell you that the negative cable has to be removed first. This is true because disconnecting the positive cable with the negative one still connected can easily cause a serious electric arc that may even be life-threatening. Even though the battery only has 12 volts, a shorted car battery can actually generate several hundred amps in a short time, leading to a total power of more than a thousand watts. This can cause damage to your vehicle, and is a safety hazard for you as well.

removing the battery holddown bracket

Unfastening the Battery from Its Tray

Right at the end, when you think you know all about how to remove car battery connections, will be when the hard part comes. After disconnecting the battery you have to physically remove it. To do that, you’ll need to remove the securing bracket, which might be held together by nuts and bolts similar to the ones keeping the terminals connected. Using a wrench or a ratchet and socket, you'll need to remove the bolt or nut that secures the bracket to the vehicle. Be sure to place them somewhere where they won't get lost, such as the cowl or in a magnetic tray.

battery recycling graphic

Corrosion Problems and Your Car Battery

Corrosion can be a major issue, and you should wear protective gloves, safety glasses and even long sleeves, if necessary. It will appear as a fluffy or powdery green or bluish-white deposit on the battery casing, terminals and cable clamps. Sometimes corrosion can actually eat away at the clamps themselves, making removal a real pain. Depending on how much corrosive material has built up on the terminals or leaked out of the battery, you will have to take special care with every task – from removing the cable terminal ends, which may already be severely affected, to lifting out the leaking, old battery and making sure it’s removed safely. Figuring out how to remove car battery components and fasteners safely can be a difficult task, but one that you can easily complete with the right precautions and equipment. If corrosion or battery acid gets on your skin, wash it well with soap and water.

Once you've removed your old battery, take a moment to clean the area, and then you're ready to install the new battery using the reverse steps as removal. And remember to connect the negative cable last! 

Find an Advance Auto Parts store close to you.

*Car battery testing and installation available on most automotive vehicles, at most locations, unless prohibited by law.

Last updated October 5, 2021