Car battery corrosion is a common sign of battery wear and tear. But it’s not something to be taken lightly.
A corroded battery can affect your car’s electrical performance and may result in costly repairs.
Fortunately, all you need to do is give it a good spa day!
Keep reading to find out how you can clean car battery terminals in seven easy steps. But before that, we’ll also confirm what car battery corrosion looks like and share some preventive tips.
This Article Contains
- What Does Car Battery Corrosion Look Like?
- How to Clean Car Battery Terminals: A Step-By-Step Guide
- Why Do Car Batteries Corrode?
- What Problems Do Corroded Batteries Cause?
- 6 Ways to Prevent Battery Corrosion
What Does Car Battery Corrosion Look Like?
Corrosion buildup on a battery terminal appears as a white, blue, or greenish substance with a powdery, granular texture. The corrosion color depends on the chemical reaction that has occurred.
How does that happen?
When your battery runs, it releases hydrogen gas, which then mixes with the air, moisture, and salt — leading to a buildup.
While battery corrosion is unavoidable, you can try to extend your car’s battery life by keeping it clean.
Let’s see how you can do that.
How to Clean Car Battery Terminals: A Step-By-Step Guide
Although you can clean corroded battery terminals by yourself at home, we recommend taking your car to a repair shop or calling a mobile mechanic. Having a professional perform the job is always a safer option.
But if you can’t reach a mechanic, here’s what you can do to clean battery terminals at home:
Step 1: Gather Equipment and Check the Battery
You’ll need the following supplies:
- A cleaning solution (this can be baking soda and water, a battery cleaning agent, vinegar, or plain drinking soda)
- A battery brush or stiff wire brush for scrubbing
- Pliers and a wrench to detach the battery cables
- Rags and rubber gloves to clean the battery terminals
- Safety glasses for eye protection
Caution: Before you start on the battery, check for any bloating, swelling, or electrolyte leakage.
If you notice any of these signs, get a mechanic to look at them instead.
Step 2: Detach Battery Cables
Before detaching each cable end, ensure the car ignition is off. Then, disconnect the battery cables in the correct order to avoid electrical system issues.
Start by detaching the negative cable (black) from the negative battery terminal FIRST. It’s the one with the “-” sign or the abbreviation “NEG” printed on the battery case. Once done, disconnect the positive cable (red) from the positive terminal. The positive battery terminal has the “+” sign or the abbreviation “POS” printed on the battery case.
But what if the battery cable is heavily corroded and won’t detach?
If a battery terminal is too rusty and you have a locked terminal clamp, don’t force it, or the battery post might break. Instead, apply a terminal cleaner and leave it on for a few minutes to loosen the connection.
Step 3: Inspect the Cables
Check each battery cable for any damage, as it’s a common reason your car won’t start. If the cable insulation is cracked, frayed, or corroded, you’ll need to replace it with a new one.
Step 4: Loosen Car Battery Corrosion
You can use three solutions to clean car battery corrosion.
Note: Don’t let any cleaning solution or corrosion elements fall on other engine parts. To ensure that, it’s best to take the corroded battery out of the engine bay beforehand.
Now, let’s go over those simple steps:
A. Baking Soda Solution
Using baking soda and water solution is a simple and effective method to clean battery corrosion.
You can apply this in two ways:
Take one tablespoon of baking soda and mix it with a cup of water, then pour it onto the corroded battery terminals. Alternatively, coat the corroded areas with baking soda first, then slowly pour the water on them.
How does it help?
The baking soda solution triggers a chemical reaction that loosens the corrosion. You can also dip an old toothbrush in vinegar or lemon juice and apply it over the baking soda. After a few minutes, scrub and rinse with water-soaked cotton swabs.
Note: For heavily corroded battery terminals, soak a paper towel or tissue paper in the baking soda solution and place it on the corroded terminal. You can also soak the battery clamp in a cup with the baking soda solution and leave it for about 20 minutes before scrubbing.
B. Battery Terminal Cleaner
A commercial-grade battery cleaner in the market typically comes as a cleaner spray bottle. The cleaner helps clear the corrosion and neutralize the battery acid. It’s worth purchasing if you have a heavily corroded battery.
Ensure the battery terminal cleaner doesn’t touch your paint job because some cleaning agents can permanently stain.
C. Fizzy Drinks
This may seem odd, but any soft drink with carbonic acid (fizzy drink or soda) can loosen battery corrosion.
However, these drinks contain synthetic sugars and phosphoric acid, which can lead to engine damage. So, only use this as a last-ditch attempt if you can’t get any other battery cleaner.
Step 5: Scrub Clean Battery Corrosion
Next, scrub the battery with a wire brush or battery terminal brush to remove the loosened gunk. You can even use an old toothbrush if nothing else is available.
Use the battery brush to repeat the process for the terminal clamp.
Step 6: Rinse and Dry
Once you’ve removed the corrosion, rinse each terminal and clamp with clean water. Let it air dry, or wipe it down with a rag. You can also use an air compressor to speed up the drying.
Apply a protective grease like petroleum jelly onto the clean battery terminals as part of preventative maintenance.
Step 7: Reconnect the Battery
When reconnecting a car battery terminal, follow the reverse order of steps you took when detaching the battery. Reattach the positive battery terminal (red) FIRST and then the negative battery terminal (black).
Use a wrench to ensure each cable end is tightly secured, as loose connections can hinder charge transfer between the battery and the engine.
Note: It’s essential to know the difference between corrosion and sulfation. You can easily remove corrosion with regular battery maintenance. However, sulfation usually means severe damage to the battery.
So when you notice a corroded battery terminal or cable connectors, the wisest thing to do is call a mechanic ASAP.
Now that we’ve learned how to clean a car battery terminal, find out what causes car battery corrosion.
Why Do Car Batteries Corrode?
From an overcharged battery to chemical reactions, here’s a quick look at six of the most common causes of battery terminal corrosion:
1. Vented Hydrogen Gas
The conventional lead-acid battery contains an electrolyte solution of sulfuric acid and water.
A chemical reaction in the battery generates an electric current, producing hydrogen gas released through the top venting blocks. The gas can also leak through the area where the battery post meets the plastic casing.
This vented hydrogen gas and acid vapors from the battery react with other gasses and substances in the engine compartment, resulting in corrosion.
Sometimes, the location of corrosion can also indicate battery issues. For example, an undercharging battery may indicate corrosion on the negative terminal. A corroded positive terminal means the battery is overcharging.
2. The Lead Acid Battery Leaks Electrolyte Solution
A tipped or damaged lead acid battery can leak electrolyte solution. If the battery acid leaks, it can accumulate on the terminal and cause corrosion.
3. An Overfilled Car Battery
Lead-acid batteries must be topped up with battery water or distilled water when the electrolyte level is low.
But if overfilled, the car battery will leak electrolytes through the vents, which can flow over the metal terminals and corrode them. So, remember to pour the distilled water only up to the highest marker and no further.
4. Overcharged Car Battery
A faulty voltage regulator or alternator can overcharge the battery and increase its temperature.
How does this lead to corrosion?
The electrolyte volume will expand inside, resulting in leaks on the battery’s exterior. In severe cases, the solution can boil, releasing acidic gasses through the vents. The leaking sulfuric acid steam or liquid can cause corrosion on battery terminals.
5. Chemical Reaction on Copper Clamps
The copper in the terminal clamp is a good conductor of electricity and doesn’t rust easily. However, leaking sulfuric acid vapors from the battery, when combined with electrical current, can lead to the formation of copper sulfate, which causes corrosion.
Always clean the blue-green copper sulfate on a corroded terminal, as it’s a bad conductor of electricity.
6. Old Battery
Car batteries have a lifespan of 3 to 5 years, after which they are vulnerable to corrosion. An old battery with corroding metal terminals will drain faster, and you’ll end up with a dead car battery.
Although small amounts of corrosion buildup might look harmless, it can lead to severe issues if left untreated.
Up next, dive into the frustrating troubles that come with corroded batteries.
What Problems Do Corroded Batteries Cause?
Here are some issues you’ll face if you have a corroded automotive battery:
- Decreased battery life and performance
- Unstable electrical current flow between the battery and the engine can lead to insufficient power and affect your battery’s charging system
- Difficulty in starting the vehicle
- Electrical components like the air conditioner and onboard computer can malfunction due to unstable battery performance
So, how can you prevent battery corrosion?
Let’s find out.
6 Ways to Prevent Battery Corrosion
Some measures you can take to prevent car battery terminal corrosion are:
1. Get Battery Terminal Protectors
Using battery terminal protectors like ‘felt battery washers’ is one of the easiest ways to protect your battery. Similarly, you can use anti-corrosion pads to prevent corrosion between a battery post and a terminal. They best suit top and side post batteries.
However, before installing them, remember to apply some protective grease to prevent potential buildup on the top of the battery terminal.
2. Use a Protective Coating
You can use dielectric grease or petroleum jelly on the battery terminal to prevent corrosion. Dielectric grease lasts longer than petroleum jelly when exposed to engine heat as it’s silicone-based. Alternatively, you can also use a rust inhibitor spray.
3. Resolve Battery Charging Issues
If you think you have an undercharging or overcharging problem, you may have a faulty voltage regulator or alternator. If that’s the case, take your car to a mechanic to rectify the electrical fault.
4. Copper Compression Terminals
Consider using copper compression terminals at your battery terminal ends. These are made from tinned copper and allow a full 360° contact with the battery cable, which helps distribute the electric current evenly and prevents corrosion.
5. Have a Regular Auto Maintenance Schedule
To keep your car battery in top condition, you should get preventative maintenance services to check your battery acid levels and look for other troubles.
6. Switch to a Lithium Battery
If you have a plug-in hybrid vehicle, consider switching to lithium batteries for a better-lasting battery.
Lithium batteries are sealed, so you don’t have to worry about acid leakage or harmful vapors. These batteries can last for at least 12 years and require minimum maintenance.
While these tips can help prevent corrosion, it can still creep in over time and cause significant battery issues. When that happens, your best option is to get a battery replacement.
Get Squeaky Clean Car Batteries With AutoNation Mobile Service
Car battery corrosion can lead to electrical problems, such as charging instability and trouble starting. That’s why it’s essential to keep your batteries clean.
And if you need help with a battery issue or a simple battery maintenance service — AutoNation Mobile Service is here for you!
We’re a mobile auto repair solution that offers a 12-month | 12,000-mile warranty on all repairs. Even better, our mechanics can resolve all your automotive issues directly from your driveway.
Get in touch with us for a battery service or engine repair.