A Guide To Car Battery Corrosion (Causes, Prevention, Removal)

A car battery becomes corroded when it comes in contact with liquid or chemical substances.

Liquid substances cause battery terminals to rust with time, and when they become rusted, it prevents effective power transmission from the battery to the car starter. It can also make the engine of the car jerk and affect the car’s headlights and brake lights.

Battery corrosion can only occur on the battery terminals. A careful and regular observation of your car battery will prevent your battery terminals from getting corroded. But If your car battery terminals are already corroded, they can be cleaned with vinegar, coke, or soda solution.

For an elaborate explanation of the causes, prevention, and removal of battery corrosion, keep reading as I go into it in detail. 

What Is a Corroded Battery?

A corroded battery terminal is frequently characterized by green, white, or blue flaky substances on the battery terminal. 

old car batteries

Causes of Car Battery Corrosion? 

There are numerous causes of battery corrosion, and below are the common causes of corrosion of car batteries.

  1. Leakage of hydrogen gas: This is one of the primary causes of battery terminal corrosion. The chemical reaction in the battery converts acid into electric current, which in turn releases Hydrogen gas into the atmosphere via the battery vents. Corrosion is caused by the reaction of this vented hydrogen gas with other gases and materials in the engine compartment. The position of corrosion may occasionally be a sign of a battery problem. Corrosion on the negative terminal is a common sign of an undercharging battery. On the other hand, if the corrosion affects the positive terminal, the battery is often overcharging.
  2. Chemical Reaction in the Copper Clamps:  Since copper is a good conductor, it should be mentioned that it does not rust easily. Despite this, when an electric current flows through it, combined with the battery’s leakage of sulfuric gases, copper sulfate can be produced, leading to corrosion. When copper sulfate cannot conduct electricity properly, problems with your car will result. Blue-green precipitation on the copper terminals will be one of the things to take into account. 
  3. Overfilling the car battery: Battery water needs to be added sometimes to some lead-acid batteries (not all car batteries are available in refillable designs). Overfilling a battery can cause the electrolyte to spill through the vents, overflow onto the metal terminals, and corrode them. The topmost marker on the battery should be the maximum added level.
  4. Battery overcharge: Your battery may become hot if you overcharge it. The added heat can cause the liquid inside the battery to expand, enabling corrosive liquid to leak out of the vent holes and onto the battery cables. 
  5. Bad Car Alternator: Alternators make sure your battery is charged while it is in operation. However, if the alternator is damaged, it won’t work well and can stop providing a powerful charge to the battery. The battery won’t get a full recharge as a result. When a battery receives an insufficient recharge, white crystals begin to build up on it, indicating corrosion and signaling the need for a full recharge. 
  6. Battery Connectors: Some battery connectors might cause corrosion due to an interaction between them and the sulfuric acid in the battery. For instance, when aluminum and copper connectors are exposed to sulfuric acid, the result is a reaction that corrodes the car battery.
  7. The Battery’s Age: A battery should not be used for a long period. If your car battery is getting to the end of its 5th – 7th year, it should be replaced. 

Ways of Removing Battery Corrosion

Before starting any corrosion removal process, ensure you put on a rubber glove and get all the necessary materials (soda solution, toothbrush) ready. Check the battery cables and clamps for any damage before applying any cleaning substance to the corroded parts to prevent further damage to the battery.

You would need a wrench to disconnect and reconnect the battery cables. The type of wrench you need depends on your car battery’s terminal configuration. To avoid electric shock, turn off the ignition.

  1. Usage of Baking soda solution: This method can efficiently remove corrosion from the battery while neutralizing its acid. Put the baking soda and water solution on the battery terminals carefully. After waiting a few minutes, use a toothbrush to scrub off the corrosion on the battery terminal carefully. After this, you use a neat cloth to clean the battery terminal thoroughly. After this process, we now have a battery terminal free of corrosion. Lastly, after the work has been done, you must dispose of the remaining soda solution, and you can now wash all the instruments (glove and soda solution can) and your hand with soap and neat water. Then you return the clamps to their positions. This baking soda and water solution removes corrosion, but if you want to know how to clean car battery corrosion without baking soda, read on, as there are other ways to get the job done. 
  2. Usage of Coke solution: Using a Coke solution is another thing you can use in cleaning battery corrosion. Coke contains some chemicals that quickly get rid of corrosion on different surfaces. Pour the coke over the terminals that are corroded gently. With the help of your brush, scrub it away. After cleaning everything, you run enough hot water over it to altogether remove the coke. During these processes, ensure to rinse the parts that coke liquids have stained on the batteries because they can dry off on the battery quickly. However, after the above steps, there are other compulsory things to do to finalize the process, which are;
  3. Usage of Air Compressor, Towel, or Cloth: It’s critical to dry the battery after cleaning properly. If you want the battery to dry faster, you’ll need a towel, cloth, or even an air compressor.
  4. Usage of Anti-Corrosion Pads, Petroleum Jelly, Terminal Protection Spray: You can prevent corrosion of your battery in the future by using petroleum jelly, battery terminal protection spray, or battery anti-corrosion pads after the cleaning. 
old car battery

How To Prevent Battery Corrosion 

  1. Monitor Your Driving Behavior: Keep an eye on your driving habits. To extend your battery life, you should not entirely deplete or overcharge it. For example, if you’re going on a long trip without your car or won’t use it much, you should disconnect your battery’s terminals to prevent it from discharging. It’s also vital not to use a lot of electric consumers in your car when the engine isn’t running to avoid draining the battery, and it’s best to go for a lengthy drive now and then so the generator has enough time to charge your battery.
  2. Regularly Check Your Battery: Endeavor continuously checks your battery regularly. If your battery is always overcharged, it could be because your generator isn’t working correctly. If your battery continuously discharges after charging or after long journeys, there could be an issue with your battery or an electric component in your car that releases it constantly. Corrosion on your battery’s positive terminal indicates that it has been overcharged, whereas corrosion on the negative terminal indicates that it has been discharged. That’s why it’s crucial to check your battery’s terminals frequently to ensure it’s neither overcharged nor discharged.
  3. Dielectric Grease: Dielectric grease on the battery terminal is another way to prevent corrosion from forming. To apply the oil, disconnect the cables from the battery and use it to both terminals. Battery terminal grease of this type is available at hardware and auto parts stores.
  4. Replace the car battery: This has to be the easiest and safest way to prevent corrosion. Because a leaking car battery leads to much battery deterioration, you may need to replace it soon to avoid it happening again. It would help if you replaced car Batteries every five years to ensure that they remain in good working order. It is not good enough to manage a damaged car battery.
  5. Anti-Corrosion Washers: These washers are pads that contain certain chemicals that work to prevent corrosion. These washers will assist and prevent corrosion from forming on your car’s battery terminal. All you need to do is Detach the battery cables, insert the washers, then replace the cables, beginning with the positive and ending with the negative.
  6. Usage of metal protector: Using AMSOIL Heavy-Duty Metal Protector is an excellent option. It protects terminals against corrosion by covering them with a protective coating. You may also use it as a rust-prevention undercoating for your vehicle.
  7. Replace damaged battery cables: Battery cable connections that are damaged or corroded should be replaced; If you’ve detected evidence of significant corrosion on the car battery terminals, you may have also spotted it on the vehicle’s cable connectors. In some cases, you can safely remove the corrosion without causing more damage to the surface, but badly corroded cable connectors beyond repair may need to be replaced entirely.  This doesn’t mean you have to replace the entire cable; you can remove the old connections and replace this component on both the positive and negative lines – another inexpensive fix available at most auto parts stores.


If you followed the above instructions carefully by now, you should be able to clean corroded car battery terminals like a professional. Also, you should have had a deep knowledge of the major causes of corrosion and the best way to avoid getting your car batteries corroded. 

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