Why Do Batteries Corrode On Terminals

When most people think about corrosion, they imagine rust on metal surfaces. While that’s certainly one form of corrosion, it’s not the only one. In fact, corrosion can occur on any conductive material, including battery terminals. So why does this happen, and what can you do to prevent it? Read on to find out!

Why do batteries corrode on terminals?

Corrosion is essentially an electrochemical reaction. When two dissimilar metals are in contact with each other in the presence of an electrolyte (like water or acid), they form what’s known as a galvanic couple. This couple creates a small electrical current, and the resulting chemical reaction causes one of the metals to corrode (or rust).

However, why does battery corrosion happen? The two most common culprits in battery corrosion are the terminals and the cables. The terminals are made of a different metal than the battery, so they form a galvanic couple when connected. And since water is an electrolyte, it can easily seep into the cable connections and cause corrosion.

The build-up of corrosion on battery terminals is a common problem, and it can be caused by a variety of factors.

One of the most common causes of corrosion on battery terminals is exposure to moisture. This can occur when the battery is exposed to rain or snow or when the terminals are not properly covered and protected from the elements.

Another common cause of corrosion on battery terminals is exposure to chemicals. This can occur when the battery is exposed to acid rain or other chemicals or when the terminals are not properly covered and protected from exposure to harmful chemicals.

Improper installation is also a common cause of corrosion on battery terminals. This can occur when the cables are not properly connected or when they make contact with other metal objects.

And finally, poor maintenance is also a common cause of corrosion on battery terminals. This can occur when the terminals are not cleaned and/or coated with a protective sealant or when the cables are not properly tightened.

If you’re experiencing corrosion on your battery terminals, there are a few things that you can do to address the problem.

  • The first step is to clean the terminals and remove any built-up corrosion. You can use a wire brush or a special terminal cleaning tool to do this.
  • Once the terminals are clean, you can coat them with a protective sealant. This will help to protect them from future corrosion.
  • You can also take steps to prevent the cables from coming into contact with other metal objects. You can use electrical tape or cable ties to do this.

Remember, “prevention is better than cure”. The earliest you detect the corrosion on battery terminals, the less damage it will do. So it is a good idea to check your batteries terminals every month or so and clean off any corrosion with a wire brush.

Does corrosion mean bad battery?

Not necessarily. Corrosion is the natural process of a battery wearing down over time. However, if corrosion is excessive, it can lead to a bad battery.

Excessive corrosion can be caused by a number of factors, such as leaving your battery sitting for an extended period of time without using it, exposing your battery to extreme temperatures, or having a low-quality battery. So if you’re experiencing excessive corrosion, it’s important to determine the cause and take corrective action.

If your battery is showing signs of excessive corrosion, it’s best to replace it with a new one rather than try to repair it. There are many quality batteries on the market, so be sure to choose one that will meet your needs.

How do I keep my battery terminals from corroding?

Proper maintenance is the key to keeping your battery terminals from corroding.

One other way to keep your battery terminals from corroding is to apply a thin coat of petroleum jelly. This will help to prevent any moisture from getting in between the terminals and causing corrosion.

In addition, to prevent corrosion, ensure that the cables are properly connected and that there is no excess metal or plastic hanging off of the terminals. If there is, then these extra materials can corrode and cause damage to the battery.

You can also use a battery terminal protector to help keep the terminals from corroding. These protectors are basically little caps that fit over the top of the terminals and help shield them from moisture and debris.

Can corroded terminals drain the battery?

It’s possible for corroded terminals to drain a battery, although it’s not likely.

Corrosion can cause a lot of electrical resistance, which means that electricity won’t flow as easily through the corrosion as it would through metal. This can cause the battery to discharge more quickly or even completely.

In most cases, however, the corrosion is not severe enough to completely drain the battery. And if it is severe enough to drain the battery, then there’s probably something else wrong with the vehicle that needs to be fixed in addition to replacing the corroded terminals.

Does pouring Coke on car battery get rid of corrosion?

It can help a little, but it’s not a permanent solution. It also depends on what type of corrosion it is. If it’s a simple build-up of dirt or grime, then Coke may help to dissolve it and make it easier to clean off. But if the corrosion is caused by severe battery acid, then pouring Coke on top of it will only make things worse, as the Coke will react with the acid and create even more corrosive compounds.

The acid in the Coke will dissolve some of the corrosion on the battery terminals, but it won’t completely get rid of it. If you do this often, you’ll just be pushing the corrosion down onto the battery cells, where it can do more damage.

The best way to clean battery terminals is to use a terminal cleaner or a wire brush. You can also use baking soda and water to create a paste that you can spread on the terminals and then rinse off with water. This will help remove any corrosion and gunk buildup.


All of this corrosion on battery terminals can lead to some serious problems, like a dead car battery. But it’s easy to clean and prevent with a little bit of regular maintenance. So make sure you give your battery terminals a good cleaning every once in a while, and you’ll be able to avoid any costly repairs down the road.

About the author, Phil Borges

Phil Borges is a battery aficionado. He's written extensively about batteries, and he loves nothing more than discussing the latest innovations in the industry. He has a deep understanding of how batteries work, and he's always on the lookout for new ways to improve their performance.