Why Do Battery Terminals Corrode? (11 Reasons Why)

As any car owner knows, a vehicle battery is required to start and drive an automobile. Consequently, you must investigate the cause of battery deterioration.

However, how would you know the reason why your battery terminals corrode? Of course, it is one crucial thing to discover if you want to know the solutions. So, let’s find out more!

Why Do Battery Terminals Corrode?

1. Electrolyte Leakage

The electrolyte or electrolyte vapors emitted from the top of the battery are the most frequent cause of battery corrosion.

Further, the acidic electrolyte may precipitate on top of your vehicle’s battery due to hydrogen gas naturally generated from the battery.

Since the connections and the battery terminals are made of different metals, another kind of corrosion develops between them.

Finally, sulfation is corrosion that gradually develops inside the battery over time.

2. Hydrogen Gas Leakage

The battery converts acid to electric current when there is an electric charge.

In some cases, the hydrogen gas in your battery will not just flow but also make its way into the surrounding environment.

The reaction of other chemicals and materials with this leakage will provide the ideal setting for corrosion to your battery terminals.

Therefore, you might be able to identify different battery problems based on the battery’s side in which the corrosion occurs.

3. Overfilled With Water

If you overfill your automobile batteries with water, the electrolyte may leak out via the vents and cause corrosion to the battery terminal connections.

Therefore, be careful to fill your battery only with the appropriate volume of water. It can help you prevent your battery terminal from corrosion.

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4. Corroded Copper Clamps

Copper is a fantastic, powerful conductor that resists corrosion well.

However, copper sulfate is created when electric currents flow across the copper terminals, which causes battery terminal corrosion.

Further, the presence of a bluish deposit on copper terminals could be copper sulfate. Unfortunately, copper sulfate is a poor conductor, making it difficult to start your car.

5. Old Battery

If you have had your car battery for a while now, regardless of how well you maintain it, you shouldn’t be shocked to discover some corrosions.

Batteries deteriorate as people do. A battery typically has a lifespan of five years. However, prepare to purchase a new battery after five years.

The battery’s health can depend on various circumstances, of course. But if you notice corrosion or other indications of deterioration before five years, it’s time to replace your battery.

6. Overcharging The Battery

Overcharging The Battery

Your automobile battery’s terminals may corrode if your alternator is just a little bit overcharging it.

When your car is running, use a multimeter to check your voltage to ensure it isn’t charging above 14.5 volts while the engine revives.

But, it can also result from frequently utilizing a car battery charger too vigorously.

7. Sulfation

Over time, repeated charging and discharging cycles will gradually wear down the terminals and cause corrosion around them; this is known as sulfation.

It can be a problem for some batteries that have been left sitting for a long time, particularly sealed lead-acid batteries, which do not have vents to allow gases to escape during charging.

These are known as deep cycle batteries, but they can also occur on smaller sealed lead-acid batteries if left unused for long periods without charging them up again at least once every month.

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It happens when your car has been parked in the garage all winter. Then, you return in springtime only to find that your car won’t start because your old battery has not been charged adequately.

8. Electrolysis

The most common cause of battery corrosion is electrolysis. Electrolysis occurs when a current flows through the internal resistance of a battery.

The result is that an electrolyte solution is created within the battery cell.

This solution then reacts with the electrodes and creates an ionic compound that provides electrons to transfer energy from one electrode to another.

Unfortunately, this reaction can cause excessive electrochemical reactions in your lead-acid battery resulting in accelerated wear and tear on your battery’s terminal posts and terminals.

9. Due To Electrochemical Process

Corrosion is a natural reaction of the metal to its environment.

So, corrosion is an electrochemical process in which an external agent, whether air, water, or another metal, reacts with the surface of a metal.

In addition, chlorides and sulfates are common corrosion agents that may cause your battery terminals to corrode.

10. Excess Heat From The Battery Or Charger

Temperature and humidity have an impact on batteries. They will act in a way that is inconsistent with their standard specifications when they are too cold or hot.

It results from utilizing the battery in a location that does not meet its specifications rather than a flaw in the product’s design.

Further, batteries will malfunction, bubble, bulge, produce sparks and fires, harm your device, or explode if they are subjected to high temperatures.

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In addition, extreme heat-related battery terminal corrosion can shorten typical automotive battery life.

11. Excessive Vibration

Excessive vibration from driving on uneven roads or using an off-road vehicle for an extended period is another factor that might cause corrosion or harm to your plates.

Further, it explicitly targets batteries that aren’t appropriately sealed to shield themselves from contamination by water and dust, which soon results in corrosion.

If those vibrations last too long, it may harm the connection between the battery and the plates. As a result, they will rust and degrade much more quickly than usual.

Of course, the issue could worsen if water and debris get through the battery-covering vents.

Notably, dust accumulation surrounding the battery terminals restricts airflow, raising its temperature and improving corrosion conditions.

To know more, you can also read our posts on why your car battery keeps dying, why your alternator is not charging your battery, and why your battery light is on


Overall, having your battery examined by an expert is the best way to avoid battery terminal corrosion.

Of course, nothing is more beneficial than letting an expert evaluate your batteries and search for any “red flags” that could indicate future problems.

And heed your car’s warnings; ignoring them could result in adverse events later.

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