How to Clean Corroded Car Battery Terminals

Just like any other part of your car. Your battery is not safe from corrosion. Just like the corrosion that attacks the body panels of your car, corrosion can attack your battery terminals and cause issues. If you have corrosion present, you will need to know how to clean corroded car battery terminals.

Battery corrosion is caused by the release of electrolyte vapors that are stored inside of the battery case. If you are not familiar with battery electrolyte, you are not alone. It is the mix of sulphuric acid and distilled water that coats the lead plates inside of your battery.  The electrolyte allows the electrical charge that is created in the battery to travel through the battery and to the terminals.

When the electrolyte is released from inside of the battery it causes significant battery terminal corrosion if not repaired quickly. Normally this electrolyte stays inside of the battery and does not cause any issues.  Battery age as well as over charging of the battery are some of the things that can cause leakage of the battery electrolyte. 

Corroded battery terminals are one of the main causes of shortened battery life. Not only does corrosion of your battery terminals cause shorter battery life but it can also decrease the performance of your battery as well. It can be the difference between starting your car on a cold winter morning and having an unplanned day off because your car will not start. 

One of the reasons that performance is decreased is caused by the creation of stray current. Or more formally known as transient current. This is when the corrosion on the battery provides a path for current to flow across the top of the battery instead of through the cables. This can cause the battery to constantly discharge eventually causing a dead battery. 

Easy to spot corrosion

Thankfully it is easy to spot battery corrosion with nothing but your eyes. No special tools required. When inspecting the positive and negative battery terminals of your vehicle you need to look for what I call, “A crusty build up”. Now I know, maybe that is not the best terminology to use here. However you will know what I mean when you find it. 

Another way of identifying the corrosion on the battery terminals is by color. Battery corrosion is a whitish-green or whitish-blue type of color. It is a very unique color and is easy to identify when compared to other fluids and items you may have under your hood. 

Once we have identified that we have a corrosion issue, we need to clean the corrosion. So let’s find out how to clean corroded car battery terminals. 

  1. Remove the battery cables

First step in this process is removing the battery cables from the battery. Remove first the negative battery cable followed by the positive battery cable. Ensure that the cables are located away from the terminals and properly secured to allow easy cleaning. It is better if you are able to remove the battery from the vehicle. Depending on the vehicle you are working on, certain batteries are difficult to remove so they will need to be cleaned inside of the engine bay.

  1. Inspect the battery cables

Once you remove the battery cables from the battery you will need to inspect them. Corroded battery terminals also means corroded battery terminals. I have seen terminals fully corroded causing them to be unusable. If the cable ends are in poor shape, replace them before reinstalling the battery.

  1. Clean and neutralize the corrosion

 Now that we have the cables out of the way we need to create a cleaning solution. Trust me, this is going to be a flash back to high school chemistry. We are going to clean the battery corrosion which is created by acid, so we need to use something to neutralize the acid. 

A simple solution of ⅓ cup of baking soda to 1 cup of water mixed in a spray bottle will allow us to clean the battery. Coat the corrosion with the baking soda cleaning solution and let it sit. You will see the baking soda solution start to bubble, this means it is working at neutralizing the battery acid.

Coat the battery cables 3 or 4 times with the solution while waiting roughly 5 minutes in between. Using an old toothbrush clean up any hard to remove corrosion from the positive terminal and negative terminal of the battery. Coat battery posts again with the cleaning solution and repeat as necessary to remove all the corrosion that is present.  

  1. Rinse and dry

Once the terminals are clean make sure you rinse the area very well. When the corrosion that was removed contacts other components of your car it will lead to corroded areas of those parts. Flush the entire area very well ensuring all the cleaning solution and corrosion is rinsed off. Allow the battery to dry before continuing the next step. If you have access to an air compressor you can also use compressed air to dry the terminals.

  1. Prevent future corrosion

Nothing is worse than spending the time cleaning your battery terminals and having the corrosion reoccur. Now that the battery terminals are clean and dry I suggest putting on something to prevent corrosion from reoccuring. There are felt battery washers that are installed below the battery cable ends to prevent corrosion. You can also use petroleum jelly (Vaseline) to coat the terminals before re-installing as well. I have had good luck over my career by spraying lithium grease over the battery terminals as well as the cable ends after installation.

  1. Re-install battery cables

Re-install your battery cables. Install the positive cable first followed by the negative cable. Ensure that the connections are tight after you install the cables. 

Be careful not to overtighten the cable ends as they are easily damaged.

Congratulations on cleaning and protecting your car battery. Now you can answer the question, how to clean corroded car battery terminals. Once the battery cables are re installed in the vehicle you should ensure that you get your battery tested. 

Your local auto parts store will be able to test the battery if you do not have a load tester or battery tester to complete the test. Also make sure that your battery is not due for replacement. The average battery lasts from 3-5 years depending on how the vehicle is driven and the climate that you live in. 

If you are within the 3-5 year timespan, we would recommend replacing the battery. This will ensure that your battery is operating in the best possible condition. This will reduce the chance that you will be left with a dead battery when the weather gets very cold or very hot. 

Hopefully you have learned much more about the process of cleaning battery terminals in your car. Remember, clean battery terminals will ensure that your battery has the best possible performance and lasts a long time in your vehicle. Giving you trouble free performance. 

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