How To Clean Battery Corrosion

Last Updated on March 30, 2023 by Chase Manhattan

Corrosion on car battery terminals is a common thing. Batteries with corroded terminals can cause a battery to keep dying if not cleaned on time because a car battery won’t charge if the connection is poor. If treated on time, the corrosion will not cause any long-term problems. Here is how to clean battery corrosion.

1. Get a battery cleaner, a battery brush, cloths, pliers, and a wrench. 
2. Remove battery. 
3. Apply the cleaner.
4. Scrub the terminals with the brush.
5. Rinse with water in a spray bottle.
6. Wipe with clean cloths.
7. Reconnect the battery. 

If you have a corroded car battery, you can clean it yourself. The process is relatively simple even for beginners. However, if you don’t feel like you are up for the job, ask a mechanic to do it. They won’t charge too much for this.

This is a guide on how to clean corrosion on battery terminals. If you are going to be doing this yourself, follow the steps below. I will explain everything thoroughly. You will also find out why batteries corrode and how to prevent that.

Why Do Batteries Corrode

Most first-time drivers and car owners don’t even know that car batteries can corrode. That’s why so many corroded car batteries eventually die and get replaced. Flat-acid batteries are prone to corrosion.

Car batteries will eventually start corroding without protection and maintenance. The electrolyte solution inside the battery releases hydrogen which leads to a chemical process that leads to corroded terminals.

Unlike the corrosion you find at home on metals, corrosion on batteries has a specific blue and white color. It kind of looks like a powder cleaning solution. Although most car batteries corrode on their own, sometimes it’s the owner’s fault. Here are the reasons why batteries corrode.

• Battery leaks cause corrosion.
  Some flat-acid batteries are prone to leaks when they are tipped over. These batteries also require topping, when you put too much water, the solution will start to leak. Closed batteries that don’t leak when tipped over will leak after damage. When this happens, the leaked electrolyte solution will cause corrosion. [Source]
• Leaked hydrogen gas causes battery corrosion. 
  There are batteries that are more resistant to corrosion, and ones that are less resistant. Naturally, flat-acid batteries release hydrogen gas. There are vents for the gas but sometimes that is not effective. So, the gas makes its way to the terminals and causes corrosion.
• Old batteries are very prone to corrosion.
  Car batteries have an average lifespan of 3-4 years. When the battery gets old, the solution inside changes which leads to chemical reactions that both weak the battery and corrode the terminals.
• Bad charging causes corrosion. 
  A problem with the wires or the alternator can overcharge or undercharge the battery. When overcharged, batteries expand which leads to leaks, and in turn, corrosion. Undercharged batteries lose a lot of the solution which again leads to corrosion.

[Related Article: Why Does My Car Battery Keeps Dying?]

How Does A Corroded Battery Affect Your Car

A corroded car battery should be cleaned as soon as possible. The sooner you notice the corrosion, the higher the chances are that the battery will live. Corrosion can completely ruin a battery beyond repair.

Corrosion affects the capacity of the battery and how the battery is charging. So, it messes up two crucial things for a healthy battery. At first, the corrosion won’t affect your car’s performance at all. In due time, you will start experiencing problems with starting.

Mainly, corrosion will mess with the current, so the battery will not provide enough cranking amps. The capacity of the battery will die which means the lifespan of the battery will significantly decrease.

This means that the battery won’t be charging properly, it will struggle to start the car, and will eventually die.

Cleaning Corrosion On Car Battery Terminals

Follow this step-by-step guide on cleaning corroded battery terminals. Read this thoroughly to avoid any damage to the battery.

1. Get all of the needed equipment for cleaning a car battery. 
   Don’t do this with half of the needed tools. Get everything you need so the cleaning process will be as smooth as possible. You will need a car battery cleaner(you can also use baking soda with water or just a can of soda. Something to scrub with, a battery brush or a wire brush. Pliers, so you can remove the cables. And, and cloths for wiping.
2. Remove the battery. 
   It’s preferable if you do this away from your car. The cleaning solutions can damage parts of the engine if spilled. So, to avoid damaging other components, remove the battery, and clean it in a safe working place. Remove the negative terminal first, and the positive terminal second. This way, you are making sure there will be no charge left on the terminals. Remove the battery cables with the pliers, use a wrench if needed.
3. Apply the cleaning solution to the terminals.
   It’s best to do this with a dedicated battery cleaner or a baking soda and water mix. If you are using a dedicated cleaner, just pour the recommended amount on the terminals and wait for it to react a bit. The product will have instructions. If you are using baking soda, mix one cup with water and pour it on the terminals. You can add more soda on the terminal if it’s too watery.
4. Thoroughly scrub with the brush.
   Start scrubbing with the brush so the loosened corrosion will break up altogether. Keep to the terminals. Scrub the clamps that connect to the terminals if there is corrosion there as well.
5. Rinse with water. 
   Put water in a spray bottle. Hold the bottle close to the terminals and spray water. Wipe with cloth or old rags, make sure they are clean.
6. Let it dry completely.
7. Install the battery.
   This time, connect the positive terminal first and the negative terminal second to avoid problems.

How To Protect Car Battery From Corrosion

There are some measures you can take to prevent corrosion from happening again.

• Apply battery grease on the terminals. 
  You can add protective coating on the terminals to prevent corrosion. Commonly used items are battery grease or petrol jelly. The coating will defend against coating for quite some time.
• Make sure the battery is charged properly. 
  A lot of corrosion problems are due to bad charging on the battery. Regularly check your battery charge status with a multimeter to prevent any overcharging or undercharging.
• Make sure the terminal clamps are okay. 
  Bad terminal clamps can interrupt the current which can cause corrosion.
• Add battery anti-corrosion washers on the terminals. 

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