How to Fix and Prevent Battery Terminal Corrosion

When you open your hood, you will likely find a yellowish-blue substance on the terminal of your battery.

The car’s battery is vital for the smooth operation of your car. The battery controls electrical consumers such as ignition, headlights and operating the AC.

A car that is stuck in the middle or back of the road can cause embarrassment for drivers. Jumper cables may also be necessary to avoid being stranded.

After years of using the same battery for long periods, you will notice signs of terminal corrosion. You need to know what to do to stop it from happening again.

There are 5 causes of battery terminal corrosion

Battery terminal corrosion can be caused by hydrogen and electrolyte leaking from the battery. Alternator overcharging the battery for a prolonged period can cause it. Copper clamps can also cause chemical reactions.

These are just some of the reasons corrosion may occur on battery terminals.

This is a detailed listing of 5 common causes for battery terminal corrosion.

1. Hydrogen gas leakage

When the battery is charged, it turns from acid to an electrical current. Sometimes, hydrogen gas from the battery can leak and find its way to the atmosphere. Battery terminal corrosion occurs when hydrogen gas reacts to other substances.

You can diagnose different battery issues depending on the side. You can diagnose undercharging if the battery is found on its negative side. If the battery is located on its positive side, then it could be an indication of overcharging.

2. Leakage of electrolytes

Lead-acid batteries are prone to this problem. Due to age or damage, the battery’s electrolyte can leak and accumulate on the battery terminals. Overfilling the battery with water can increase the likelihood of electrolyte leakage.

3. Copper Clamps - Chemical Reaction

Copper conducts electricity well and is resistant to corrosion. But, copper sulfate is formed from electric currents passing through copper terminals. This can lead to terminal corrosion.

The presence of a blue precipitate at copper terminals could indicate copper sulfate. Copper sulfate is not able to conduct electricity efficiently, so you may have trouble starting your car.

4. Avoiding overcharging

The alternator may be slightly charging too much of your car's car battery. This could lead to corrosion. You can check the voltage of your alternator by using a multimeter while your car is running to ensure it does not charge more than 14.5 volts every time you rev your engine.

You might also find that you charge your car's battery too often with an electric car charger.

5. Don't overfill the battery

Overfilling your car's battery can cause electrolyte leakage, which is why it should be checked before you do. You can refill some car batteries, but not all.

How to fix corrosion of the battery terminal

We now know the causes of battery corrosion in cars and how we can fix them. You have a few options to clean your battery terminals.

1. Baking soda – water solution

You will need a baking soda solution, a brush and some copper sulfate removal chemicals. First, ensure that the car’s ignition has been turned off. Use your brush to get rid of some corrosion.

Continue to remove the corrosion using your brush. Clean the terminals using some water. To prevent any further damage, it is a good idea to apply some grease to the terminals. Although petroleum jelly is more durable than grease, some people prefer it.

2. Soda

Carbonic acid is a common ingredient in soft drinks. Use a sponge to clean the residue from the terminals. In the absence of baking soda and water, this works great.

3. Cleaning heavy corrosion

You can use baking soda and water to remove corrosion from the battery terminals. Start by removing the battery terminals – the negative should be first. Combine the baking soda and pour it into cups. Allow each terminal to soak in the baking soda solution for at least 20 minutes.

Clean the terminals of any corrosive substances. Put the soda solution in a clean container and create a new one. Then soak the batteries again, removing any corrosive material. Use water to clean the terminals. Dry them with a towel or a moist cloth. The terminals can be cleaned with sandpaper. Apply some grease or Vaseline and reattach the terminals – start with positive.

How to prevent battery corrosion

You can prevent corrosion by making sure that your alternator doesn't overcharge the car battery. It is important to keep your car's battery fresh and in top condition. You can also prevent corrosion with anti-corrosive sprays.

Let’s take a little more detailed look over the few ways to prevent battery corrosion:

1. Change the battery in your car

Leaking car batteries can lead to a lot battery corrosion. You may have to change your car's battery soon to stop it happening again.

To keep your car batteries in top condition, it is recommended that they be replaced every five years.

2. Terminals for Copper Compression

This clamp is one of the most popular on the market. It will prevent battery terminal corrosion. They are made out of tinned Copper and will ensure that all clamps come into direct contact with the electrical current.

3. Charge your battery

A battery with a low or high charge can cause battery terminal corrosion. The manufacturer’s manual often has the recommended battery voltage. You should not overload your car's charger with too much charge.

You can also check the voltage at idle revs with a multimeter. There is an issue if the alternator charges more than 14.5 V.

4. Anti-corrosive sprays

There are many sprays available to stop terminal corrosion. Vaseline and grease are also options if the price tag of sprays is prohibitive. You can also use coated felt pads to protect the terminals from corrosion.