Why Do You See the Corrosion on Your Car Battery? 6 Reasons to Answer Your Queries

Have you been trying to know how to start a car with a bad starter? I say you should stop that, and be concerned about your car battery. One of the reasons for the battery acting that way can be the corrosion of the battery. In the case of corrosion, there is a connection between the battery and the engine, which can weaken or just simply cut off.


It further restricts the ignition of the engine, affecting badly on the performance. If you are someone who treats cars like their babies, just like me, you’d always want to know if everything’s fine. Corrosion is something serious, and a lot of reasons can be behind it, many of which we will discuss right here.

Reasons for Corrosion of the Car Battery

1. Electrolyte Leaking Out to the Terminals

When the electrolyte in the car battery escapes out through leakages or damage, and reaches the battery terminals, corrosion occurs. This would be the case in the sealed lead acid batteries, but in the case of the flooded lead acid batteries, the batteries have much more chances to corrode, as the electrolyte can just kind of jump out of the battery while you’re too careless putting water into the battery.

2. Overfilling the Battery

We know that the electrolyte can damage the terminals when it comes in contact with them. If you put too much water in there, the chances of the electrolyte coming out of the vents and coming into contact with the terminals increase, thus this can also result in the corrosion of the battery.

3. Overcharging of the Battery

When a battery is overcharged, it heats up. The electrolyte inside the battery gets all jumpy, high on kinetic energy, and its volume increases. Thus, in both the cases, either if it’s a sealed lead acid battery or flooded lead acid battery, the electrolyte would either overflow out of the vents or sneak out of the leakages and cracks.

4. The Hydrogen Gas

The acid present in your battery produces hydrogen gas, which we inhale everyday and looks to be seemingly harmless. However, it can corrode the battery, as it mixes with other substances in the atmosphere to form the corrosion on the battery. When formed on the left terminal, it can be an indication of undercharging, while on the positive one, it indicates overcharging.

5. The Copper Clamps

Sometimes, the copper clamps that are normally used to connect the battery with the wires corrode. When it comes to Copper, it is not really reactive on itself, but the electricity passing through this makes it corrode, and Copper Sulfate is also formed. The bluish substance/precipitate you see around the battery terminals is probably this, and it can prove dangerous for the battery.

Via wikimedia.org

6. Age

Well, you do realize that you battery wouldn’t last forever, right? When the battery has performed to its fullest, there will come a time when you have to say goodbye to your battery and buy a new one for your car. Usage with time can ultimately lead to corrosion in the end, and then you know that you have to make some amendments, and accept the end of the battery.

How to Deal With Car Battery Corrosion

How to Prevent Corrosion From Happening?

Certain precautions, which I personally take care of all the time, can help you prevent corrosion before happening. And these would be:

  • Keep the batteries in a dry place for most of the time, wherever possible. Moisture promotes corrosion, and you don’t want that.
  • Never wash the interior of the car engine bay with water, as that will encourage rusting in the parts that haven’t been painted.
  • Applying grease/petroleum jelly actually prevents corrosion, and it is easily available too, so you can do it whenever you want.
  • Use the terminals and clamps that have been made out of a high quality copper.

This product I found on Amazon has been great for me. It is a spray, which is sprayed on the battery terminals. Not only does it act as a protection against corrosion, but it also increases the battery’s life as well! You can buy it right here.

If Happens, What Are We Supposed to Do now?

Some of the essential tools you should keep with you while doing cleaning the corrosion are:

  • Water
  • Clean rag
  • Wrench
  • A wire brush

What Should You Do Now?

Cleaning away the corrosion is very much simple, just follow these steps and voila! You’d have the corrosion out of the way.

  • Disconnect the terminals from the battery. Wearing gloves throughout the whole process is highly recommended, just to keep the skin safe of all the chemicals.
  • Wash the terminals with water. If the rust washes off just with the water, you’re going to have to do nothing more.
  • However, if the rust is stubborn and remains, you can make a solution of Caustic Soda, or Baking Soda, basically anything that has a basic property.
  • Dip your terminals in that solution and remain for a few minutes, and it’d be done! Wash to remove the base from the surface.

Click on this YouTube Video to see how they actually clean the corrosion up, in a detailed way.

Expert Tip: Battery Reconditioning

It’s possible your battery is going dead. You have two options in this case: you could buy a new battery or recondition the old one. Buying a new battery can be quite expensive, especially when you know what to do to make a brand new battery out of your old one. Why would anyone want to buy a new battery when you can bring your old one back to life, with almost the same power as that of a new one?

EZ Battery Reconditioning is the best battery reconditioning method I know. It is a 10-20 minute method of reviving old batteries. It is done using simple tools such as a multi-meter which you will be able to test your batteries, revive the underperforming parts, and almost double the lifespan you can get out of the average battery. 

Learning this trick amazed me and made me wish a thousand times I’d known it for years. I would have saved thousands of dollars!


So now you know that corrosion can cause several problems, and have an adverse affect on the performance of your car, but it is simply very easy to deal with. Keep checking your battery, just to be sure if there are any signs of corrosion. As a personal advice, you should rush to wash the rust off as soon as you see the corrosion, because the longer it has lived there, the more stubborn it is.

Comment down below if you have any kinds of questions, and we’re here to answer them for you!

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