Car Maintenance

What causes car battery corrosion and how to fix it

Buying a car is one of the best investments in life. And if you’re like us, treat it like a baby to make sure everything’s alright.

But have you ever opened the hood only to see your car batteries are corroded?

Yeah, that’s not a pretty sight. In addition, it can also cause dead batteries and hard starts if it builds up between your wires and terminals.

It’s a serious problem – but what causes car battery corrosion in the first place? There can be many reasons behind this and in this article we will go into detail about them.

Causes of car battery corrosion

electrolyte leakage

If your car battery is damaged and cracked, electrolytes can leak out. Corrosion occurs in sealed lead-acid batteries once these electrolytes reach the battery terminals.

Flooded lead-acid batteries have a higher risk of corrosion. Because while you’re too busy putting water in the battery, electrolytes can just pop out.

Too much water in the battery

Contacts can be damaged if they come into contact with electrolytes.

If there is too much water in the battery, there is a higher chance that the electrolytes will leak out of the vent and come into contact with the terminals. This then leads to the corrosion of your battery.

An overcharged battery

An overcharged battery heats up easily. This causes the electrolytes in the battery to become jittery, increase in volume and acquire a lot of kinetic energy.

The electrolytes can either leak out of the cracks or flow out of the vents. This can happen to both sealed and flooded lead-acid batteries.

Read also article about  What is a tune up? The most important things you should know

hydrogen gas

The acids in the battery produce hydrogen gas. It’s also something we breathe in every day and it seems so harmless.

However, it can cause battery corrosion when combined with other gases.

If it forms on the left connector, it may indicate undercharging. If it forms on the positive side, it can mean overcharging.

copper terminals

Normally copper terminals will corrode when used to connect the wires and the battery. Copper is not reactive itself, but the current flowing through it causes it to corrode.

In addition, copper sulphate is formed, which can be dangerous for the battery. If you see a bluish substance around your connectors, it’s probably copper sulfate.

age of the battery

You are aware of that Batteries don’t last foreverTo the right?

There will come a time when you will need to buy a new battery for your car when the old battery is dead. Use will eventually lead to corrosion, which is also a sign that your car needs new batteries.

Clean corrosion from car batteries

Corrosion can be cleaned with simple household items or special accessories. This can be done in just 3 steps:

Remove the battery clips

Here are the things you need:

  • battery terminal wrench
  • gloves
  • glasses

Note: Car batteries contain acid that can cause injury. Because of this, goggles and gloves are needed to protect yourself.


  1. Disconnect the cable ends by first disconnecting the negative cable and then the positive cable. Then use a battery cable wrench to turn the battery cable end nut counterclockwise.
  2. For top post batteries, loosen the nuts until there is no tension on the terminals. If you have a side post battery you will need to loosen the cable until it is completely removed.
  3. Lift the upper post battery cable end out of the clamp by wiggling the cable end.
Read also article about  How to get tree sap out of your car

Clean the battery

Special cleaning materials can be expensive. How to clean your car battery with things you already have at home:

Here are the things you need:

  • Stiff-bristled brush or wire brush
  • water
  • baking powder
  • vaseline


  1. Sprinkle enough baking soda on the connectors to completely cover them. Make sure you coat the area around them as well.
  2. Pour 2 tablespoons of water on each terminal. You’ll also notice it begin to bubble – this chemical reaction neutralizes the acid to make your car battery safer to handle.
  3. Repeat step 1 and step 2 on the cable ends.
  4. Use a stiff brush to scrub the corrosion off your car battery. Don’t forget to scrub around the wire ends and terminals inside and out as well.
  5. Rinse the battery and cable ends thoroughly with water.
  6. Use compressed air to dry your car battery completely.
  7. Apply a thin coat of petroleum jelly to the terminals and wire ends. The jelly helps conduct electricity between the connector and the end of the cable, preventing corrosion.

Professional accessories

If you already have professional consumables, do the following:

Here are the things you need:

  • Battery cleaner spray
  • battery pole brush
  • water
  • Grease (or any protective spray)


  1. After disconnecting the battery cables, spray some battery cleaner spray on the cable ends and posts. This neutralizes acid and corrosion on the battery.
  2. Soak the cable ends and battery for a few minutes. The color of the spray can even evaporate.
  3. Again spray some battery cleaner spray on the wire ends and posts. If the color changes slightly or not at all, the acid has neutralized.
  4. Rinse the battery completely with water. Again, remember to be careful with this step. Note: Some battery cleaning sprays contain dyes that may stain your paintwork a different color.
  5. Use a battery brush to clean the battery terminals and cable ends. Place it over the terminal and rotate it around the post about 5 times.
  6. Take off the battery brush and insert it into the cable ends. Invert four times to remove any corrosion buildup in the clamp.
  7. Spray battery protection on the battery poles.
  8. Reconnect the battery terminals
  9. Install the positive cable back in place. Most top post batteries will require you to wiggle or tap the end of the cable into place.
  10. Using a battery terminal wrench, tighten the nut on the terminal until snug.
  11. Install the negative cable back in place as you did with the positive cable.
Read also article about  Why isn't my car air conditioner cold?


A well-maintained car battery is the key to a successful performance. So make sure you get it checked regularly to prevent it from letting you down at crucial times.

Chloe Rimmer
Tv geek. Content practitioner. Creator. Wannabe beer nerd. Thinker. Passionate explorer. Proud bacon trailblazer. Travel fanatic. Award-winning introvert.

Related Posts

How often should I get a tune-up?

Like any other property of man, cars should undergo general cleaning, which is collectively called tuning. However, when we say tune-up, it’s more about replacing what needs to…

How often should you change your oil

Vehicle engines are typically made of metals. So imagine the intense friction created when pieces of metal work together, mostly colliding and rubbing against one another in a…

How often should you have wheel alignment done?

There are many types of vehicle maintenance, one of which is wheel alignment. In fact, wheel alignment is considered very important for all types of automobiles. It basically…

How often should you wax your car

Waxing your car isn’t just for vanity. There are actually practical reasons that will make you want to wax your vehicle right away. However, don’t get too excited…

How often to change the cabin air filter

Many car owners probably have no idea that the cabin air filter needs to be changed from time to time. To enlighten them, we will provide answers on…

How often does the coolant need to be changed

Coolant is extremely important to regulate high temperatures. It is an essential fluid for all types of vehicles. With most of us always driving to specific destinations on…