Corroded Car Battery - How to Clean and Prevent It

Car battery corrosion is often underestimated issue, but it decreases the car's battery performance and its operating life. Also, a corroded car battery can damage the rest of the electrical wiring, car body, air conditioning, and other systems that are nearby.

Car battery terminal corrosion happens when the car battery vapors, consisting mostly of sulphuric acid and hydrogen, come in contact with the battery terminals (mostly led) and battery cabling (copper) under the car's hood, heated by the engine...

Published: August 6, 2021.

Sulphuric acid vapors, hydrogen, copper, lead, and probably a few more compounds, lead to the build-up of battery corrosion, mostly consisting of bluish copper and lead sulfates, and similar salts.

Such buildup looks nasty and can damage the battery, wiring, and other parts of the car, as well it can cause chemical burns on the skin, it can damage the clothes, and similar.

Note: When dealing with chemicals like these, always wear protective goggles and protective gloves, although other protective measures are welcome, too.

A corroded car battery can be cleaned in few simple steps:

• Disconnect the Battery
• Check the Battery Cables and Terminals
• Remove the Corrosion
• Reconnect the Battery

Disconnect the Battery From the Car

Before disconnecting the car's battery, check if your car allows that - some modern cars feature electronic systems that are constantly powered by the car's battery and if the battery is disconnected for whatever reason, the engine and other subsystems may become blocked (safety system) and the car must be towed to the nearest certified car shop to unblock the electronics.

If You have such a car or you just want to play safe, before disconnecting the battery, connect the 12V car battery tender to the car.

Now, first disconnect the negative battery cable (sign "-", black cable) before disconnecting the positive battery cable (sign "+", red cable).

Also, if it is possible, it is a good idea to remove the battery completely from the car.

Check the Battery Cables and Terminals

 Now, check the battery cables and terminals for any signs of damage, including damaged insulation, it is time to replace the cables right away, or at least as soon as possible.

Also, check that the car's systems near the battery are not showing signs of corrosion damage - if present, consider taking the car as soon as possible to the nearest licensed car shop so that they can check the car more thoroughly.

Remove the Corrosion From The Battery Cables and Terminals

In order to remove the corrosion from the battery cables and terminals one may use commercial products (liquids, spray bottles, etc.) but the ordinary baking soda will do the job just fine.

So, take a glass of warm water, add a tablespoon of baking soda and mix it thoroughly.

Now, take the old toothbrush or any similar brush and apply the baking soda solution over corroded areas and brush everything thoroughly - baking soda will neutralize and clean the battery corrosion very quickly.

Note: while some people prefer to do this job using Coca-Cola or similar beverages, note that baking soda solution contains only water and baking soda, while soda beverages contain various sugars, artificial colors, sweeteners, various acids, etc. Such mixture can even damage car components even more, so if You prefer cleaning the battery corrosion with Coca-Cola, be sure to remove the battery from the car completely. Better safe than sorry.

During the cleaning, be sure that soda solution mixed with battery corrosion doesn't come in contact with other car parts - again, if possible, take the battery out of the car completely.

Instead of toothbrushes, other types of brushes can be used, including car battery terminal brushes that can be found rather cheap.

After cleaning, be sure to rinse the battery cables, terminals, and the battery itself.

Before reconnecting the battery, be sure to dry the battery using an air compressor, dry cloths, or something similar - electricity and liquids don't come together very well.

Reconnect the Battery

Now that the battery terminals and cables are clean, it is time to reconnect the battery.

First of all, check the battery cables and terminals once again - with no battery corrosion present, one can better see any potential damage.

When reconnecting the battery, reconnect the positive battery cable (sign "+", red cable) first and then the negative battery cable (sign "-", black color).

However, before actually reconnecting the battery, in order to prevent future battery corrosion, it is a good idea to place anti-corrosion pads around the battery terminals.

Such battery terminal protectors are basically fiber washers that contain chemicals that neutralize battery acid, preventing future battery corrosion.

Note: anti-corrosion pads don't last forever and in order to protect the battery from corrosion, they must be replaced periodically.

To protect the battery even further, it is highly recommended to also apply anti-corrosion lubricant or silicone-based grease.

And that would be all.

Of course, if You want, this task can be done in any certified car shop - they can also test the battery to accurately check its condition and if required, replace the battery and the battery cables with new ones.