Car battery corrosion prevention

Preventing Car Battery Corrosion: Tips and Solutions

Car battery corrosion prevention, The battery is one of the most crucial parts of your vehicle. It gets your car started- and similar to all components onboard, you need to maintain and take care of it for smooth operations. Car battery corrosion, meanwhile, is a leading cause of decreased battery life and performance.

Apart from hindering your vehicle from starting- which can be tedious in the morning when you’re heading to work- it can also lead to a plethora of other issues, including damage to other vehicle’s electrical wiring and air conditioning.

Fortunately, car battery corrosion is easy to spot. Quite often (especially with older batteries), you will begin to notice some white, green, or blue-tinged covering around the battery terminals, battery cables, and battery posts.

This accumulation of chemical trash reduces the conduciveness of the battery, leading to a transient flow stream. It’s another way of saying the corrosion can cause a malfunction due to the electrical resistance.

What Causes  Battery Corrosion 

Car battery corrosion prevention

Car battery corrosion prevention, Corrosion on car battery terminals is very common, especially among cars with a lead-acid battery. Most acid batteries are filled with sulphuric acid. The temperature of your car battery tends to alternate between hot and cold, which causes gases to escape through the vents on the battery.

These gasses mix and react with other compounds around the battery, causing the corrosion (tinged covering) you see.

That being said, you’d expect corrosion to occur when your car remains stationary for months or years. But that’s not it. In fact, it doesn’t take long to form. So if it doesn’t take long to happen, what could be the reason behind corroding battery terminals?

Battery Terminal Corrosion: Why it happens

Car battery corrosion prevention, There are various reasons carrion takes place on the terminals. The corrosion itself differs in appearance, color, and texture, subject to its cause. Below are the various common causes of battery corrosion.

Electrolyte Leakage

Car battery corrosion prevention, Electrolyte leakage is a synonymous problem among lead-acid batteries. While batteries are meant to hold the acid in a safe and solid container, leaks still have a chance.

When the electrolyte leaks out and builds up around the battery terminals, probably due to damage or lack of proper maintenance, then there will be corrosion. The probability of this electrolyte leaking is increased when you overfill the battery water.

Speaking of sealed maintenance-free batteries, the chances of electrolyte leakage is minimal, but it’s still possible. Batteries that require regular topping the electrolyte with water have a higher probability of spilling some electrolyte on the terminals. In all cases, the presence of electrolytes around the terminals will cause corrosion.

Overfull Battery

Overfilling your refillable battery with too much water can mean trouble. Not all batteries are refillable, meaning you need to double-check if you have one to make sure it is not overfilled.

It would help if you also were careful about only feeding the electrolyte without exceeding the highest markers. You might want to top the electrolyte on a cool day to leave room for the liquid to expand when the temperature of the battery increases during performances.

The fact that terminals are made with metals means that any excess flowing out of the vents will corrode them.

Chemical Reactions In The Copper Clamps

Car battery corrosion prevention, Quality clamps used to connect the battery to the wires are typically made of copper. From the basic chemistry we know, copper does not corrode all by itself.

However, in the presence of sulphuric gases from the battery vents and a little help from the current flowing through the copper clamps, copper sulfate is created, which gives rise to battery terminal corrosion. It’s simply the bluish-green crystals that form around the terminal. The stated chemical reaction can be formulated as follows:

“Cu (s) + 2 H2SO4 (ℓ) → CuSO4 (aq) + 2 H2O (ℓ) + SO2 (g)”


Car battery corrosion prevention, They say that anything above what is actually required is poisonous. Well, charging batteries is not an exception. Overcharging your battery can lead to terminal corrosion. It raises the battery temperature causing the electrolyte to expand in volume. And when you apply the thing about pressure, the electrolyte finds its way out.

Even if the battery is sealed or somewhat folded, the electrolyte will eventually flow through vents or any cracks. After all, it is the battery terminal that endures the worst part.

Also, if the alternator is slightly overcharging your car battery, it can cause corrosion on the terminals. Inspect the voltage with a voltmeter when your car runs and make sure it’s not charging over 14.5 volts when the engine is revving. Otherwise, corrosion due to overcharging can result from frequent charging your car battery with a car charger that is way too hard.

Hydrogen Gas

The reaction of the battery creates hydrogen gas. Of course, there are some in the air that we breathe every day, but that’s pretty harmless in small quantities. However, as harmless as it can be, it can cause corrosion upon reaction with other gases.

This usually causes charging issues, such that if it occurs on the positive terminal, it means that the battery is overcharging or undercharging if it appears on the negative terminal.

Battery Age

Regardless of how you maintain your car battery, if you’ve been using the same battery for a period of close to five years, then you shouldn’t be surprised to see the terminals corrode or the overall battery performance declines.

Batteries generally have a lifespan of 5 years, but obviously, various factors dictate how they age. The first sign of a failing battery will come from your engine’s performance.

Problems caused By Battery Terminal Corrosion

The most common problem with corroded battery terminals is the danger of the vehicle not starting. This can happen just any time but is usually most embarrassing when the lights shoe green and you can’t move.

Your car’s onboard components can develop issues too, due to a problematic battery. If the battery is leaking, old enough for a replacement, or the corrosion has eaten too far deep into terminals, then you should consider a replacement ASAP.

How To Fix Battery Terminal Corrosion

There’s no simple method to get rid of corrosion on your battery terminals. It all calls for a thorough cleaning. As you know, you’ll need a solvent and something tough enough to scrub the terminals. A wire brush and a battery cleaner will do.

Baking Soda (Water Solution)

You’d need some baking soda-water solution to help get rid of copper sulfate that has accumulated on the terminals. Be sure to turn off the ignition when doing this. Apply the solution to the terminals and give them a good scrub.

Thereafter, flush the solution away using clean water and put back the clamps in their correct position. In the absence of baking soda, any soft drink that contains carbonic acid can do the trick. Pour some over the terminal, and then remove the residue with a soft sponge.

Cleaning Heavy corrosion

In case the battery has excessive corrosion on the terminals, then you will have to use a baking soda water solution and an old toothbrush. You don’t have to use force if the corrosion is tough to remove. Start removing the battery clamps. The negative should be the first.

Mix the baking soda solution and put it in cups. Soak each of the clamps in the solution and leave them to soak for about 20 minutes. After that, scrub the corrosive materials on the terminals and copper clamps.

Remove the residues with water and let the battery dry or wipe them with a damp cloth. You can also use sandpaper to clean the terminals. Then apply some Vaseline or grease and reattach the terminals. Start with positive.

How To Prevent Battery Terminal Corrosion

So now, after fixing the car battery terminals corrosion, what can you do so it doesn’t happen again? There are several ways to prevent the development of corrosion on your battery terminals. They are simple and straightforward. And can be done by anyone. To keep your battery working as new, you should apply these preventive hacks on fresh or cleaned batteries.

Battery Charging

If your battery is corroding due to overcharging or undercharging, you might want to consider taking it to the mechanic to fix the electrical fault. In case the battery is undercharging because the AC is always operating or you have a powerful amplifier, you might want to make some changes to save your battery.

Anti-Corrosive Sprays

There are many anti-corrosive sprays on the market that forestall terminal corrosion. But in case you find them too expensive, grease or grease would do a nice job. We’d recommend grease over Vaseline because it can withstand heat.

Copper Compression Terminals

Copper compression terminals are usually recommended because they are made from tinned copper that keeps the whole clamp in contact with the battery terminal. These clamps are probably the best on the market when it comes to preventing further battery terminal corrosion.

Vehicle Maintenance

Car battery corrosion prevention

Staying aware of your vehicle maintenance needs as well as following the right maintenance advice is the most promising way to avoid corrosions on your car battery.

Be sure not to underutilize your battery with only short strips or drawing too much from it, maybe by using car gadgets when the engine is running. You can prevent corrosion or tackle it early to keep your battery in good condition.

The Bottom Line

Corrosion on battery terminals can be cleaned quickly with simple homemade DIY tools. That said, you could help stop corrosion before it becomes a problem to extend the battery lifespan.

The most common problem that you can experience with your car battery usually stems from leaking gas from the vent. However, the battery can also malfunction if the terminals are loose, if the battery is cracked due to being dropped, or your components speaker is mostly blaring full force even when the engine is not running.

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