Car Battery Corrosion: What Owners Need to Know

Car Battery Corrosion: What Owners Need To KnowCorrosion on a car battery is a widespread problem. The longer you have your battery, or the longer you go without cleaning the terminals, the more likely you are to develop corrosion on your battery. Let’s go over some of the main reasons and problems that it can cause.

Several things can cause battery corrosion. Overcharging can cause corrosion on the positive terminal of your battery. If both terminals are corroded, there may be a chemical reaction occurring in your battery clamps as electricity passes through them. The age and construction of your clamps can also play a role. Another common source of corrosion is exposure to the elements.

With so many different causes, meanings, and indications of car health behind corrosion on a car battery terminal, it could be helpful to have more in-depth information. That’s what we’re here for! Let’s dive into what you need to know about car corrosion.

What Does Corrosion Look Like?

Car corrosion will usually look like a somewhat crystalline, powdery buildup on your battery. It is generally white, blue, or a mixture of both. It kind of looks like your battery started either growing rocks or mold. Neither of those options is a good one when it comes to the thing that helps start your car before you go to work in the morning or drop your kids off at school.
If you take a look at your battery at you, see anything that resembles what we just described, your battery has started to build up corrosion. This problem needs to be taken care of.

What Causes Car Battery Corrosion Only On The Positive Terminal?

Car Battery Corrosion: What Owners Need To Know

If your battery is building up corrosion on just the positive terminal, this is generally a sign or an indicator that your battery is being overcharged. Have you ever left your phone on the charger for too long, and noticed when you took it off that the phone was warmer than it should be, or occasionally even hot? While the methodology is a bit different, the idea is the same.

When your car battery gets overcharged, the chemicals in the cell, specifically the electrolytes, to move around rapidly because of the excess energy they’re getting. The kinetic energy from this movement causes heat, which can be felt on the outside of the battery. The volume of the electrolyte inside the cell increases with the flow, causing the battery to swell, which can also be observed in many phones.

Once the increase in volume hits the breaking point, hydrogen gas will begin to spill through any vents, cracks, or weak spots in the battery. The chemical reaction between the gas, which doesn’t have much of a chance to escape the car, the electricity, the medal of the terminals themselves, and the electrolytes, creates the visible buildup on the terminals.

How to Prevent Overcharging

It can be hard to tell if your battery is overcharged or is overcharging until your battery begins to be affected negatively. There are some things that you can do to prevent it, and other things that you can change once you know that there is a problem.

As far as prevention goes, you can keep your car out of the sun and the heat as much as possible. This will make it much easier for your battery to swell.

Make sure your alternator works. If the alternator is running at the wrong pace, it can wreck your battery in several ways. If it goes to slow, your battery won’t receive the charge that it needs, and your car will have problems starting. Or, it won’t start at all. If it goes too fast, your battery will get overcharged. You’ll begin to get a buildup of battery corrosion, which can also make it challenging to start your car.

If you have to charge your car manually, make sure you follow the instructions carefully. Especially since you’re in charge of it, there is so much more room for human error. Unless your car has fail-safes to keep overcharging from happening, you can damage your vehicle by keeping it plugged in for too long.

How About Corrosion On Both Terminals?

Corrosion on both terminals can be an indication of a chemical reaction between the copper of the clamps and the electricity passing through them to the terminals.
There’s not a whole lot you can do to prevent this since your battery needs to stay hooked up to your car. What you can do is keep the connections dry and keep them clean. This will reduce the speed at which the corrosion will build up. If it’s often happening or building up too quickly, check the date on your battery. Older batteries will build up corrosion more quickly. Cars that are left sitting for long periods without being started are more prone to corrosion, as well.

There is also a chance that there are leaks around the terminals themselves, which would also cause buildup. Regardless of what you think may be causing it, it won’t hurt to get your battery checked out periodically.

What Causes The Battery Itself To Become Corroded (not on terminals)

This depends on the kind of battery. Specific cells need water added to them, and overfilling the battery can cause electrolyte leakage, which means corrosion.
Corrosion can also occur when the battery becomes broken or cracked, and the fluid leaks out. A typical example of this that you may have observed for yourself would be tv remotes or possibly old toys. When a battery leaks or breaks, there is a buildup in the device where the battery broke. That’s a great example of corrosion. If you see corrosion or buildup of any kind on your cell, there’s a good chance that there is a crack or a leak. You need to get your battery checked out, and more than likely, replaced.

Can I Drive With A Bad Battery?

Can you? Yes. Should you? No. Assuming that the phrase “bad battery” is comparable to “corroded or leaking battery,” you really shouldn’t. A battery with an acid leak, at worst, could explode. The acid from a car battery is strong and can damage other parts of your car, which has the potential to cause your car additional mechanical problems. A battery replacement AND additional repairs? No, thank you!

At the very least, having corrosion around the terminals on your battery can make it harder to start your car. Nobody wants to be stuck somewhere with a car that won’t start — or stuck in a car when it explodes.

Does corrosion drain car battery?

Corrosion will not drain your battery, but any battery corrosion will have an impact on the performance of the cell. Corrosion will get in the way of the charge being passed from the terminal to the battery, or the other way around, depending on how how much buildup there is.

For example, having corrosion on your battery terminals will impact the charge either going to your battery to charge it, or the charge going from the cell that is being used to start the car. While this may not have a direct effect on the ability of the battery to hold a charge, it does have a direct impact on the measurement of charge the battery is receiving. Also, the amount of charge the battery will be able to give to your car.

If you see corrosion elsewhere on your battery, the chances are good that the battery is leaking and possibly cracked. If your battery is leaking, the charge your battery can hold will be affected.
So while your terminals may be clean and transferring electricity like they’re supposed to, the available power of the battery as a whole will be less, and there is a good chance that at some point, it won’t be enough to start your car. So get it checked out! Better to be safe than stranded!

Can Corroded Battery Terminals Cause a Car Not To Start?

Yes! When the positive terminal is corroded, depending on the amount of corrosion there is on the terminal, the battery might not be getting enough of a charge to start your car.

When the negative terminal is corroded, there’s a good chance that even if the battery has the requisite charge, that it won’t all be available to start your car. The corrosion on the terminal will block the charge, and if there isn’t enough contact between the terminal and the clamp, there won’t be enough electricity available to ignite the process that starts the engine.

So while it will be for different reasons, the result will be the same. Corrosion on either of your battery terminals can prevent your car from starting.

Is Corrosion On a Battery Dangerous?

The corrosion itself isn’t dangerous, but the implications it can have to the health of your car and your battery aren’t great.
Corrosion on the terminals of the battery can be a reaction between the copper and the electricity passing through them, or it could be a leak at the base of the terminals. Corrosion anywhere else indicates a highly probable leak from the battery, which would mean that the battery itself is damaged.

If the battery is damaged, at worst, it could explode. Depending on how severe the leak is, the acid could spread to other parts of your car, causing extensive damage, which could give you a range of problems from your car not starting, to your vehicle exploding. In an ideal world, neither of those things will happen!

If you see corrosion on your battery, check it. While there’s a chance it could be benign, you don’t want to risk it.

How To Fix Corrosion On a Car Battery?

Car battery corrosion can be easily cleaned off the terminals of the battery, but if the corrosion is anywhere else on the battery, don’t mess with it.

Before attempting to clean the corrosion off the battery, make sure your car is off. It will help prevent damage to your vehicle, the car battery, and you.

All you need to clean off the corrosion on a battery terminal is a simple solution of warm water and baking soda. Once you’ve disconnected the cables, take a toothbrush, dip it in the baking soda and water solution, and scrub it away. It should clean up fairly quickly, leaving you with excellent clean terminals and cables.

Once you’ve done this, there are several things you should do before you hook everything back up.

  1. Check the battery and the cables for rips, tears, or breaks. If there is anything that isn’t whole, you’re going to need to replace it. Leaving damaged parts installed in your car is just asking for mechanical trouble.
  2. Once you’ve done that, dry everything off very thoroughly with a clean cloth. Pay special attention to any of the parts that will be conducting electricity, or pieces that will be used to secure the cables back onto the terminals.
  3. There are several corrosion preventative sprays and coatings that can be applied to the connections and terminals that will assist in the prevention of acid buildup.

Is Corrosion a Sign Of a Bad Battery?

Often, yes. But not always. Corrosion on the terminals of your battery can result from several things. It can mean a leak, which is a bad thing. It can also be a buildup as a result of a natural chemical reaction between the copper of the clamp, and the electricity passing through it to the terminal.

But, as we said, there’s still a chance that the buildup on the terminal could be from a leak, and corrosion anywhere else on the battery is pretty much never a good sign. In addition to that, if the chemistry of your battery has gone bad, or the battery is old, it will be more likely to show signs of corrosion than a new battery would or one with balanced internal chemistry. So while not all corrosion means your battery is bad, many bad batteries will show signs of corrosion.

How Do I Keep My Battery Terminals From Corroding?

Several fantastic products assist in the prevention of battery corrosion. Some are made specifically for that job, and others are products that had other original purposes, but have been discovered to work just as well! We’ll include one of each.

Sporting the claim that it will prevent corrosion for the entire life of your battery AND that it’s environmentally friendly, this spray couldn’t be more simple to use, or better suited to the task at hand. Resistant to a number of things, including but not limited to evaporation, moisture, and shock, it’s the perfect product for someone who is looking for something specifically designed to prevent corrosion on their battery terminals. Click here to buy it from Amazon.

That’s right! A number of people have found that this standard household product does a great job of preventing corrosion on your battery terminals. Just coat the clean, dry terminal before attaching the cable, and you’re good to go! It is that easy. If you don’t already have some, you can click here to check it out on Amazon.

Can You Spray WD40 On Battery Terminals?

If for some reason, you were using it to clean the terminal or loosen a fastening, you can do that, and it won’t hurt your battery. However, if you’re trying to use it as a preventative measure against corrosion, that won’t work. Battery corrosion isn’t rust, so WD40 isn’t going to stop it since an entirely different chemical reaction is the cause of the corrosion.

How Do I Know When My Car Needs a New Battery?

The easy answer is, “if your car isn’t starting, you need a new battery.”  But there are several warning signs that you can look out for.

If the car does start, but the engine has to turn over a couple of times before it does, then your battery is on it’s way out. You will need to get a new one before you get stranded somewhere.
If the battery is showing signs of stress, like excessive or frequent corrosion, or swelling, then there is something wrong with the battery. It needs to be replaced.
If you have to jumpstart your car frequently, that’s a great sign that your battery can’t hold a charge, and your vehicle needs a replacement.

Get an ohmmeter, find out what your battery’s recommended readings are, and test your battery. This is a great way to get a precise reading on what kind of condition your battery is in, and not leave anything to chance.
If any of the lights in your car dim when you press the accelerator or the brake in your vehicle while your driving, this is a good indication that your battery isn’t able to give your car the power it needs. You may need to replace the battery.

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