Car Battery Corrosion – What Are The Causes and How to Remove It

If you’ve owned a car for an extended time, you understand that corrosion builds around the battery. It starts at the terminal and, at first, seems harmless but may potentially cause damage to your car engine. Neglection of these problems can even lead you to have battery failure or engine seizure. Therefore, it is important to understand what causes corrosion in the battery of your cars.

What Is Corrosion?

Corrosion build-up in your battery can differ in color from being white to green or bluish. It is often powdery, and even salty in taste. Although it is not advised to taste it, this corrosion starts forming around the terminal of your battery. Over time, it keeps building and turning into a chunk that eats your battery.

It is a natural occurrence. You can not control or stop the corrosion of metals. However, there are many ways to either maintain and prevent this corrosion for a prolonged time frame.

How Does Corrosion Build-Up in Batteries?

Primarily, corrosion is common in batteries that use acid and lead. Sulphuric acid is a common acid poured in these batteries.

The corrosion builds up over time due to the shift in the temperatures around the battery. It leads to the formation of gases that exhausts from the battery vents. However, this ventilation can also lead to a mixture of gases with anything in their immediate surrounding. When they mix up with an agent or element, it causes corrosion.

Corrosion does not have any particular time-limit or requirement. It can form at any time, and the severity depends on the quality of the battery, acid, elements in contact, and several other factors.

What Are The Causes of Battery Terminals Corrosion?

As you have understood, there are many factors contributing to the build-up of corrosion. However, as stated, corrosion can differentiate in colors and textures. Therefore, you need to distinguish between these reasons to rectify the problem adequately.

Similarly, it can also help you in determining when you need a change or service for the battery:

Too Much Water:

A battery requires water to operate. If your battery runs out of the water, then it will ‘dry out’ and wouldn’t operate optimally. The opposite is also true. If you fill your battery with excessive water, then the overflow will lead to corrosion. Therefore, it is important to keep track of the electrolytes and only fill up to the maximum mark.

Take care of the temperature, as well. It is ideal for filling the battery in a cool or room temperature to gauge it adequately. This will provide electrolytes enough space to expand without causing corrosion.

Excessive Charging:

You might have heard that it is not a good idea to charge any battery for a prolonged time. The same goes for the batteries of your car. Overcharging a battery wouldn’t only cause corrosion, but also reduce its performance.  You might have seen batteries budge, or expand when they are charged for too long. It is due to the rise in temperature that makes the electrolytes react.

Hence, it leads to the release of the pressure from the battery either through vents or by forming cracks. Even batteries with proper ventilation and pressure control can’t completely contain pressure. Thus, you will end up with a corroded battery due to the overflow of the electrolytes.

Hydrogen Release:

The gas is present in the atmosphere, which is usually harmless. However, when it releases from the battery, there are other factors such as temperature and pressure. We can not forget that batteries also contain acid and other agents. Relatively, hydrogen gas is released in a higher quantity from the batteries.

It either happens due to overcharge or undercharge. An undercharged battery is an exhausted battery without any power. Either way, the hydrogen gas released can be a contributing factor to corrosion build-up mainly because it will mix with other elements and agents to cause unwanted reactions.


As you might have noticed, electrolytes seem to be a primary cause of corrosion. Usually, batteries have a build to contain the acid and control other reactions. Most of the batteries even come with ventilation or pressure control.

However, electrolytes can still leak out, especially around the terminals, causing corrosion. While most of the high-grade and maintenance-free batteries will discard the need for many cautions, during a filling or charging, it is important to keep a note of electrolytes overflow.

The Copper Clamp Reaction:

Copper is used as clamps because of its exceptional longevity. It does not corrode by itself and usually has better conduction of electricity. This is the primary reason most of the electric wires use copper, and the same goes for the battery.

However, when the leakage of acid or gases is ensured from the battery, it can very-well mix with the copper to cause a reaction. The primary cause of this corrosion is sulphuric acid and the release of its gas that mixes with copper.

By mixing with copper, copper sulfate is produced that corrodes the terminals. These are the primary reasons for blue or greenish crystallization corrosion around the terminals.


A battery is bound to malfunction sooner or later. However, most of the modern batteries last up to 5 years. This is also a good point to note that when you get a lifetime warranty or guarantee, then it is only a 5-year plan or promise for the batteries.

No company actually means ‘your lifetime,’ but the standard ‘battery’s lifetime.’ Overtime, your battery will start to wear out and corrode. If you use the battery past the 5-year time frame, it will only cause problems for you.

The Consequences Of Corrosion

Modern vehicles are full of circuits and modules that rely upon batteries to function. Even when your car is not running, the battery is providing them a little backup to function optimally.

These are the list of problems you might face with corroded battery:

  • The car will not start, even if the lights are showing green
  • Fault in the automatic or electrical system of the car
  • Car’s computer system might malfunction
  • Errors in the automatic functions and gauges (or scales)
  • Further neglection can lead to potential bust or explosion in a battery that could eat at your car’s parts
  • Alternatively, the engine might seize and require replacement

Overall, it is a good idea to inspect the battery on a scheduled routine. If there is excessive corrosion or other problem, it is a good idea to ask for professional insight.

What is the Solution For Battery Corrosion?

If your battery is not eaten by the corrosion yet, you can very-well save it. That’s right, as long as it is a basic build-up, a complete cleaning procedure will do the job. Therefore, these tips might prove to be handy to retain a long life for your batteries.

Make sure that you have a container to prepare any of the following solvents. Additionally, you will need something to scrub the terminals to remove corrosion. A small brush, preferably a toothbrush, will do a commendable job.

Also, make sure that the car is not powered, and the engine is shut down before cleaning, to prevent any mishaps.

1. Carbonated Drinks

Any soda or carbonated beverage contains carbonic acid. This is one of the best ways that require minimal scrubbing. All you have to do is buy one of these carbonated drinks and pour it, albeit carefully, over the terminals.

Give it a minute before you use a sponge or brush to start scrubbing. You will notice that it cleans just like a baking soda.

2. The Baking Soda

If what you’re noticing on the batter is the copper sulfate corrosion, it’s time for baking soda to do the magic. Mix some baking soda with water and use it to pour and scrub over the terminals. Wherever you see the bluish-green corrosion, you can use the baking soda solution.

Make sure to scrub well and then use clean water, obviously distilled, to clean up the system. After that, you’re good to go. Just let it dry out a bit.

What to do In case of Intense Corrosion?

The two given solutions are best for cleaning the batteries. However, what if the corrosion is too dense or heavy for your battery? You should never scrub or rub the battery with excessive force.

Anything excessive is bad, including the scrubbing. Therefore, you need to employ a soaking method.

Soaking Method

Step 1:

Dip a towel, piece of cloth, or paper into the solution of your soda and water.

Step 2:

Then place this drenched piece onto the terminals. Now, this is a work of patience, and you might have to wait around half an hour for the solution to be soaked inside the terminals. You can return to see if there is any change, potential removal or ‘easing’ of the corrosion.

Step 3:

Try scrubbing or removing delicately, don’t use force. If it does not show any improvement, soak again and let it sit for another 30 minutes or so. Over time, you will be able to remove the corrosion.

Preventive Measures You Should Take

Now, we have talked about the causes of corrosion and how to fix or clean it potentially, right? You have also learned about the consequences. But is there any way to actually prevent corrosion from building in the first place? Well, the good news is that modern innovations have led us to a wide range of options.

Here are some you can try to prevent corrosion:

  • The market is full of various anti-corrosive agents, especially sprays, that provide anti-corrosion qualities.
  • Grease, vaseline, and other forms of lubrication is also a good way to prevent corrosion. Make sure to keep the temperature in mind.
  • If your battery is overcharging, then take it to the mechanics. Undercharging can use some measures such as reduction of other performances like AC and amplifiers. However, if the problem persists, a mechanic is the best solution.
  • Perhaps use better clamps that are produced from tinned copper and cover the entire terminal.
  • Regular car maintenance and service is also the best way to maintain battery performance. Actually, it is an excellent way to maintain all functions of the car.
  • Make sure that your battery is not under or over performing.

Take Care Of Your Battery

You now understand the causes and solutions to battery corrosion. However, experience also matters to maintain good battery performance. Try to make it your weekly habit to check the car’s battery is you do not want to invest in your car’s services and maintenance regularly.

Don’t wait for the pungent smell, or for the battery to blow out before you realize the problems. Use adequate preventive measures, always remember the cleaning methods, and understand the causes.

Otherwise, you know the consequences. So, have a high performing car with the best battery life.