You may have noticed an unusual whiteish-blue substance on your battery terminal when you opened your hood at least once before.
The car battery is critical for normal operation for your car. It not only provides power to start your engine, but it also supplies power for all electric consumers, such as your ignition, headlights, radio, or AC. No one likes to stall out in the middle of the road for obvious reasons. So why do batteries corrode?
The most common cause of battery corrosion is hydrogen or electrolyte leaking from the battery. Over time, another reason why corrosion may occur is because the alternator has slightly overcharged the car battery. And it is not unusual for chemical reactions to take place with copper clamps.
Your battery terminal corrosion will likely only start to appear after years of use with the same battery, so you should try to understand the cause and you will need to fix it. Examples of the top 5 reasons your battery terminal is corroding will soon be described in more detail.
What Causes Battery Terminal Corrosion?
#1. Hydrogen gas leakage.
The battery generates an electric current from acid. Occasionally, hydrogen gas escapes from the battery into the of the atmosphere. Eventually, it combines with an outside compound, and this is the cause of terminal corrosion on the battery.
Different problems associated with the battery will present on the battery terminal surface depending upon the side the corrosion forms. If it is on the negative terminal, it is a sign of undercharging. If it is the positive terminal, it is a sign of overcharging.
#2. Electrolyte leakage.
The problem is similar to lead-acid batteries. As the battery gets older or is damaged, its electrolyte may leak and build up on the battery terminals. The likelihood of electrolyte leaking increases if one overfills the battery water.
#3. Chemical Reaction In The Copper Clamps.
Copper is a good conductor and does not corrode easily. When electric current passes through the copper terminals, it makes copper sulfate which results in corrosion at the battery terminal.
A bluish precipitate on the copper terminals is likely copper sulfate. Copper sulfate does not conduct electricity very well and you will start to having trouble starting the vehicle.
#4. Overcharging.
If your alternator overcharges your car battery, you may run into some corrosion on your car battery terminals. To check your voltage with a multimeter, you want to check your voltage while running the car and revving the engine, and ensure that it is not reaching over 14.5 volts.
This can happen if you are frequently overcharging your car battery with a car battery charger as well.
#5. Overfilling the battery.
Overfilling your car battery can result in electrolyte leaking, as has been noted before. While not all batteries are refillable, you should definitely check to make sure it’s not overfilled if you have one.
How to Fix battery terminal corrosion
Now that we are aware of possible causes of car battery corrosion, we need to know how to correct it. There are a few options to remove corrosion from battery terminals.
#1. Baking soda – water solution.
If you want to remove copper sulfate corrosion from the terminals, you will need to make a simple baking soda solution and use a small brush. First, ensure that the car ignition is OFF. Disconnect the battery terminals and use your brush to remove some of the corrosion buildup.
Pour the baking soda solution over the terminals and continue brushing off corrosion. When you are complete, rinse off the terminals with clean water.
As a precaution, you should smear some wheel bearing grease on the terminals to prevent further corrosion. Some will use petroleum jelly but it does not last as long as grease.
#2. Soda.
Most all of the soft drinks we consume contain some carbonic acid in them. You can pour some soda on the battery terminals and use a soft sponge to remove the residue. This is an option in lieu of using a baking soda-water solution.
#3. Cleaning heavy corrosion.
If you happen to have excessive corrosion on the battery terminals, you will need to take the baking soda-water and an old toothbrush. Begin again by removing the battery terminals – negative first. With three or four cups, mix the baking soda solution and soak the terminals in each cup. Allow the terminals to soak for 20 minutes in each cup.
Continue brushing off all corrosive materials (spraying soda solution in the process). Mix a fresh baking soda-water solution. Soak the terminals again, continuing to brush off all corrosive materials. Rinse with clean water and dry; towel or allow to air dry.
You can also use sandpaper to clean the terminals if desired. Once clean, put on a thin coating of grease or Vaseline and reattached the terminals. Reattach positive terminal first.
How to Prevent Battery Corrosion
To prevent battery terminal corrosion, first ensure the alternator is charging the car battery properly. Additionally, having a somewhat newer battery that is not defective or leaking can be helpful. Anti-corrosive sprays do also help.
Let’s review some ways to prevent battery corrosion:
#1. Replace the car battery.
If the car battery is leaking then replacing it prevents a lot of battery corrosion from coming back as quickly. It is often recommended to try to swap them out every five years or run the risk of leaking.
#2. Copper compression terminals.
These clamps are one of the best varieties on the market and will help prevent more battery terminal corrosion. They are tinned copper and ensure that the whole clamp interacts with the electric current.
#3. Battery charging.
One reason for battery terminal corrosion is a battery that is overcharged or undercharged. This often could be found in the owner’s manual for the car. You don’t want to charge your battery too hard with your car battery charger, which is why it is good to check the voltage as well.
Check the voltage of the battery when the car is revving on idle and a multimeter. If the battery is charging more than 14.5 volts from the alternator, there is an issue with the alternator.
#4. Anti-corrosive sprays.
There are sprays you can buy on the market to help prevent terminal corrosion. If the spray is expensive, you could look into using Vaseline or grease. There are also felt pads that you could purchase that are coated to help prevent battery corrosion.