How To Clean Corroded Battery Terminals

There’s nothing more frustrating than a car that won’t start. Corroded battery terminals could be the cause.

However, battery corrosion can be easy to spot. Just look for a white, green, or bluish-tinge around your battery terminals, posts, or cables. 

The great news is that cleaning the corrosion is quick and easy. Also, it helps to extend the life of your battery as well as boost the power.

Read on to find out how simple it is to resolve this car issue.

There may be affiliate links in this article. You can read more about this in my disclosure.

What causes car battery corrosion?

As sulphuric acid is released from the battery, it contains nitrogen gas. The gas then reacts to the surrounding air and causes the green, bluish, or white tinge in your battery terminals.

If you have a refillable battery, adding too much distilled water can cause the liquid to overflow. This excess water can contact the battery terminals and corrosion occurs.

Overheating your battery can cause the internal liquids to pour out of the vents. The liquid then spills onto the battery cables. 

Expect corrosion on older batteries. Typically those that are between 5 to 7 years old. 

How to remove corrosion from your battery

Corrosion is easy to remove. However, you need the right gear. Here is a list of items you should have for the job:

• A wrench
• Protective gloves (batteries contain sulfuric acid, so you don’t want to get hurt)
• Baking soda
• Water (or battery cleaner)
• Battery terminal brush (you can use an old toothbrush)
• A cloth/rag
• Petroleum jelly (this can be replaced with Terminal Protection Spray or Anti Corrosion pads)

Now that you have the equipment, let’s start taking the corrosion away.

Step 1: Disconnecting the battery cables

Get your wrench and start by removing the negative cable first. Commencing the process with this cable keeps you safe from electric shocks or being burnt.

Then remove the positive cable.

What size wrench you use is determined by if the terminals are located on the side of the battery or on the top. Side terminals need 5/16” (8mm) wrench.

Top terminals require either a ⅜” (10mm) or ½” (13mm) wrench. 

You can identify the negative cable by looking to see if it has “NEG” or a minus symbol (“-”). Also, these cables are usually black in color.

The positive cable is marked as “POS” or has a plus symbol (“+”). Typically positive cables are red.

Step 2: Check the cables aren’t damaged

Damaged cables can be one sign of why your car is having trouble starting. Look carefully at each cable to see if there are indications of corrosion, fraying, splitting, or cracking.

Replace any blemished cables. 

Step 3: Remove the corrosion

When it comes to removing the corrosion from your battery terminal, there are a couple of methods you can try. 

Using a battery cleaner

Battery cleaning agents consist of compounds that not only clean but protect your terminals. It can be tempting to go cheap, but you should spend that little bit extra for a commercial grade cleaner.

These are specifically made to give your battery what it needs as well as extend your battery’s life. 

Water and baking soda

Mix some baking soda in a bowl of hot water. Use your brush to apply the solution to the corroded parts of your battery and cables.

Pour a small amount of your water onto the battery terminals and watch for the reaction (a bubbling of the solution). Now your terminals are safe to handle as the acid has been neutralized. 

Step 4: Rinse

Get your brush and scrub away the corrosion from the affected areas. 

If you are using a commercial grade cleaner, then use caution when applying it. If you get some onto the paintwork of your vehicle, it can cause discoloration.

Once you have finished removing the corrosion, rinse the terminals and cables with cold water.

Step 5: Drying

Allow everything to air dry before reconnecting the battery. 

If you’re in a rush you can use an air compressor to speed up the drying process. 

Step 6: Prevent further corrosion

To minimize the build-up of corrosion, cover your terminals with anti-corrosion pads. The best ones to go for are pads that contain compounds that prevent corrosive buildup. 

Alternatively, you can use petroleum jelly. Cover your terminals and cable ends with a thin layer of jelly. 

If you want to use battery protector spray, shake the can well. Next, spray an even coating over your terminals, cable connectors, bolts, and brackets. 

Step 7: Reconnect everything

Now that the job is over, it’s time to put everything back together. 

It’s a simple task of reconnecting the cables back to the battery. If you removed the battery from its bay, place it back in.  

You need to follow a reverse order from the initial disconnection process. That is, connect the positive terminal first and then the negative terminal.

This prevents you from shorting the battery. Additionally, only a portion of the car now has power, so if you accidentally touch something, you will be fine.

Connect the negative first and you can sustain a serious injury. 

Feel free to add additional substances that will prevent corrosion. You won’t be damaging anything and it will enhance the battery life as well as boost power. 

Do I need to replace my battery?

A car battery typically lasts up between 6 to 10 years if properly maintained. Corrosion can cause the life of the battery to be shortened.

Yet, that doesn’t necessarily mean you have to rush out and buy a new battery. 

However, if your battery is getting older or starts leaking frequently, then you should consider replacing it. 

The battery is a critical component to starting your car. When this starts to fail, then you are going to be faced with frustration as you turn the key and nothing happens. 

Make checking your battery a routine

You may clean the inside and outside of your vehicle on a regular basis. Yet, how often do your open the hood of your car and clean the engine components?

Waiting until you have engine trouble is too late. As they say “Prevention is better than the cure”.

Keep an eye on the motor and the critical parts of your vehicle’s engine. That includes the battery and its cables. 

Having a regular routine of looking at the engine and testing everything not only extends the life of your vehicle. It saves you from frustration.

There is nothing worse than a car refusing to start when you’re in a hurry.

Last update on 2023-09-22 / Affiliate links / Images from Amazon Product Advertising API