Car Battery Corrosion can be frustrating when you open your hood and see it staring back at you, or worse, your car won’t start and then you notice the corrosion. By then, you’re already late to get somewhere and you don’t have the time to clean it.
Prevention is the key — we look at all stages of battery corrosion in this article.
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Car Battery Corrosion
Car battery corrosion is one of the most common reasons for battery deterioration. What causes car battery corrosion? How do you deal with car battery corrosion? How do you prevent car battery corrosion? These are the questions that I’ll be answering through the course of this article.
A good quality car battery, that is well maintained, could last as long as 10-years. Though, on average, car batteries last for about 5-years. Taking good care of your car battery will obviously improve battery life.
Excessive car battery corrosion may even prevent your car from starting. Allowing corrosion to buildup over time can hinder the flow of electric current, causing a low voltage to your starter. This can result in the car having difficulties starting, an may even prevent the car from starting at all.
Removing and preventing car battery corrosion is more important than one may have thought.
VIDEO | How to Clean Corrosion from your Car Battery
What Causes Car Battery Corrosion?
All car batteries use a chemical reaction, there are electrolytes that are energized when certain elements receive an electric charge. These electrolytes then discharge the energy when they come into contact with the terminals.
While there are several methods of achieving this reaction, most car batteries use a lead acid reaction. It is quite common for a blue-white powdery substance to accumulate on the terminals of a lead acid battery. This is car battery corrosion.
Car battery corrosion is usually caused by hydrogen gas being released from the battery acid. When combined with other elements, this causes a corrosive residue to form. Hydrogen gas corrosion is recognized by a white powdery substance forming around the battery terminals. Though the blue substance would be copper sulphate, this is an additional reaction between the copper battery clamps and the lead terminals.
If the negative battery terminal is corroded, it is most likely that the battery is undercharging. This could be the result of a faulty alternator, or bad connections in the battery (or car wiring) system. Though, this won’t always be the case. If you test your battery, with the engine is running using a multimeter, this should be easy to diagnose. It’s always best to get the correct voltage specification from the manufacturer, but this would be around 13.7 – 14.7V. The ideal battery voltage, with the engine switched off, is about 12.6V. Any reading significantly different to these, will indicate a battery charge problem. In which case, you should check your alternator, or have it checked by a professional auto electrician.
Corrosion on the positive battery terminal may be an indication that your battery is overcharging. This can also be tested using a multimeter. A faulty rectifier or voltage regulator can be the root cause of this.
If you overfill your battery with water, this can cause acid leakage which may cause battery corrosion. An older battery may also leak battery acid, or gas, simply as a result of aging. So, you may not always be able to trace the problem by checking the battery voltage.
Regardless of the cause of the battery corrosion, you will need to clean the battery terminals to remove any trace of corrosion. Once cleaned, there are several methods of preventing battery corrosion from reoccurring.
How to Clean Car Battery Corrosion?
It’s quite simple to clean car battery corrosion, and it’s likely that you already have everything you need. Quick tip: if you notice mild corrosion, in its early stages, you can pour some soda from a can onto the terminals. Though, this is very much a quick fix, and won’t necessarily resolve the problem entirely. It’s always better to thoroughly clean the car battery terminals.
You can buy a can of car battery terminal cleaner, though this won’t save too much time. I always clean car battery terminals using a solution of baking soda, dissolved in warm water.
Before you begin, do the necessary preparation. Remember that there is it’s highly likely that will be a fair amount of battery acid in the corrosive residue. This can damage your skin, eyes, and clothing. Even the fumes that are released whilst cleaning can cause damage.
Wear clothing that covers your arms and legs. Preferably old jeans and a long sleeved shirt. These garments may be damage by battery acid spill. Eye protection is also recommended, as acidic gasses may cause eye damage. Make sure not to breath in directly over the area that you are cleaning, the fumes can be toxic.
Having taken care of the basic safety precautions, you need to disconnect both the positive and negative clamps from the battery. Of course, this means resetting your radio and clock, but that can’t be avoided. At least, some modern cars have a lithium ion internal battery that keeps these circuits powered when the battery is disconnected. Also check that your car doesn’t have a security lockout when the battery has been disconnected. Check your owner’s manual with regard to disconnecting your battery, as some cars need you to perform a specific security routine after disconnecting the battery.
To remove car battery corrosion, pour a little of the backing soda solution on the affected terminal and use a brush to remove the residue. I keep an old toothbrush for this type of cleaning. You’ll be surprised how times an old toothbrush can come in handy, not just to clean car battery corrosion. I have one in my toolbox at all times.
Once you’ve removed all the battery corrosion residue, rinse with clean water.
Preventing Car Battery Corrosion
As my grandma always said: “Prevention is better than cure”. Preventing car battery corrosion is quick, easy, and very necessary. The reaction of the hydrogen gas, or copper lead sulphate reaction, requires other elements present in the air to cause corrosion.
The best way to prevent battery corrosion, is to seal the terminals from the atmosphere. You can use grease. Common multi-purpose grease is fine for this purpose. Petroleum jelly will work as well. The only problem, when using regular grease or petroleum jelly, is a dust buildup. Though, this doesn’t cause any harm, it just looks bad. You can use a silicone, dust free grease, or buy a formulated sealant for a car battery. These won’t collect dust.
You need to make sure that you cover the entire battery terminal and the clamps that connect to the vehicle wiring. Any exposed surface can result in the formation of battery corrosion. You should also ensure that you never overfill the battery water, as this can easily cause hydrogen gas, or battery acid, spillage.
Battery acid is extremely dangerous, it can burn your skin and eyes, dissolving clothing in seconds. So, always follow the correct procedures when topping up a battery and performing common battery maintenance tasks.
If you have any doubts, have your battery checked by an authorized battery dealership. Once a year should be fine.
Another tip to ensure that your battery remains in top condition is to keep it fully charged. If you don’t drive regularly, use a battery charger (at least once a month) to keep your battery in a good state of charge. This would also be true, if you regularly drive short distances. The time it takes to fully charge a battery after starting a car will vary, depending on the condition of the alternator and the battery. A roundtrip of less than 5-miles may very well mean your battery has not fully charged. This will be of even greater importance, if the vehicle only drives at low speed. A battery charges more effectively at higher engine revs.
If you’re going to leave your car standing for a prolonged period, make sure the battery is fully charged before doing so. Remove the battery terminals before storing the car. Before reconnecting the battery, it is advisable to charge it to full using a battery charger.
Following these basic battery maintenance tips will help reduce the occurrence of car battery corrosion. It will also prolong the life of your car battery and improve battery performance.