What Causes and How to Prevent Car Battery Corrosion

A car battery is an underrated part until something happens. Car batteries can last anywhere from 2 to 5 years, depending on how well you take care of them and the initial quality. However, if you don’t maintain it correctly, you’ll notice corrosion around the wires or cables or see a white powdery substance on top of the battery.

If a car battery is corroding, it may be due to over/undercharging, excessive vibrations when driving, extreme temperatures, or poor maintenance. Quick fixes include replacing the alternator, changing the shocks, covering the battery with an insulation kit, and regularly inspecting and cleaning it.

These are just a few causes of car battery corrosion. The rest of this article will describe these and other common causes of car battery corrosion in detail. Read on for in-depth information on these problems and how to address them.

Car battery corrosion.

1. Overcharging the Battery

Typically, a fully charged battery has about 13.7-14.7 volts of electricity moving through it when the engine is running and measures about 12.6 volts when the engine is off. However, if your car’s alternator is faulty or worn down, it can produce more electricity than needed. In other words, it causes overcharging. Since the battery is susceptible to fluctuations in power, this can lead to battery corrosion.

A slight increase in voltage causes hydrogen gas to form around the cathode plates, producing bubbles that split open the protective coating. As the process continues, the lamination between plates begins to break down.

The typical symptoms of a damaged or overcharging alternator include:

  • The battery light or voltage meter on the dashboard comes on.
  • Overheating issues, especially in hot weather.
  • The engine dies when you try to start it up after turning it off.

How To Fix

The easiest way to fix this problem is to have your car’s alternator replaced either by a professional or yourself. However, you must keep a constant eye on it. Keep in mind, if this has been a problem for a while, the damage may be irreversible, and the battery might not be savable at this point.

2. Undercharging the Battery

Another common cause of battery corrosion is undercharging. This happens when the battery isn’t getting enough power to keep up with demand. Undercharging is caused when a car’s alternator or wiring is faulty, but most commonly, it’s caused by a worn-out car battery.

If you’re experiencing issues with starting, but everything else is fine, then this could be the issue.

How does undercharging lead to corroding?

When there isn’t enough electricity moving through the system, the chemical reactions that take place inside the battery are affected. This gradually causes corrosion on top of the plates and wires until they break down completely.

If this happens and you notice the battery terminals are loose, then it has become completely unusable.

Other signs of undercharging include:

  • The battery light comes on (if your car has this feature).
  • You see corrosion on your battery cables.
  • The car doesn’t start when you turn the ignition key.

How To Fix

You can fix this in one of two ways:

  • Install a new car battery
  • Have the current one checked out at a local shop

A new battery will resolve the issue immediately, while checking things out determines if there’s some underlying problem with the wiring system or alternator. Just be sure to get these things repaired, if that’s the issue.

In general, it’s also a good idea to check all wiring in the engine bay to ensure no clogs are in the coolant system.

3. Excessive Vibration

Another cause of corrosion or damage on top of your plates is excessive vibration while driving over bumpy roads or having an off-road vehicle for too long. This mainly affects batteries that aren’t sealed well enough to protect themselves from dust and water contamination, which quickly leads to corrosion.

If those vibrations continue for too long, they can damage the battery’s connection with the plates. This will cause them to corrode as well as break down much faster than usual.

The situation can be made worse if dust and water enter the battery cover vents. Notably, dust builds up around the battery reduces airflow, causing it to heat up even more, thus creating a much better environment for corrosion to take place.

Additionally, whenever moisture enters these vents, it begins a chain reaction with all components in the system. Eventually, they break down completely and lead to complete battery failure.

How To Fix

The most straightforward way to fix an excessively vibrating car is by replacing your vehicle’s shocks and struts. This can be done at a local garage or dealership as part of a more extensive service. If that doesn’t work, you may also need new tires.

Additionally, dirt and dust should be cleaned out from the vents on your battery compartment as soon as possible before it starts corroding any internal components. A local mechanic can also do this for you, if necessary.

Excessive vibrations also cause damage to wiring, so make sure everything in your engine bay is working correctly.

4. Extreme Temperatures

Extreme temperatures are always detrimental to car batteries. They cause batteries to fail much sooner than usual because of the corrosion damage on the internal parts. This is especially true for hotter climates with too much exposure to the sun and cooler climates with icy weather.

When our bodies get chilled, we shiver, sending signals to our central nervous system telling us we’re feeling cold and to bundle up.

However, your car’s battery doesn’t have this option, so it starts wearing down when it gets frigid. Furthermore, batteries in colder climates have a much harder time delivering current to the starter and other electrical components.

How To Fix

You can prevent excessive temperatures from causing corrosion damage by using an insulation kit, such as this Design Engineering Insulation Kit (available on Amazon). Not only is it highly resistant to vibrations, it can also withstand temperatures up to 2,000 °F and has a titanium wrap for improved reliability and durability.

Also, remove (or cover up) your car’s battery during the winter, and make sure to keep it in a warmer area of your garage. Be careful it’s not too warm so that it starts failing because of high heat.

An ideal environment is around 40-60 °F. It also helps to ensure all cooling fluid levels are okay before doing anything else. This is important because cold weather can drain these components quickly, which causes severe problems later on.

Note: Extreme temperatures are already detrimental to batteries, so an AGM battery is required instead of a standard flooded cell if you live in a hot or cold location. They cost more money upfront but last way longer than standard batteries do, thus saving you money in the long run.

If you’re in the market for one, I recommend this XS Power AGM High Output Battery. It’s vibration-resistant, spill-proof, and can be mounted anywhere.

5. Poor Maintenance

Poor maintenance can be divided into improper battery care and lack of battery upkeep.

In other words, not doing the right things to take care of or maintain a car battery can lead to corrosion and other problems. This includes letting your battery drain below 12 volts, which allows lithium sulfate crystals to build up inside it.

Also, constantly discharging and recharging your battery causes crystallization on the plates. In turn, this causes an internal short-circuit that damages the entire system from within out.

In general, it’s best to avoid dropping below 50% charge level, as this risks short-circuiting your entire system, which leads to problems like corrosion.

How To Fix

Battery maintenance is an integral part of car ownership, and it’s important to keep up with regular inspections and proper procedures, such as cleaning out the vents. Batteries also need to be kept in well-ventilated areas to prevent them from catching fire.

Some batteries come with a “limited life” indicator to inform you when it needs to be replaced, but you can always contact the manufacturer if you have any questions or concerns about this.

If your battery is mysteriously draining too quickly, there may be other factors involved, such as faulty wiring and connections. Thus, it’s critical to ensure everything works properly before trying to replace anything.

Here’s a great primer on car battery maintenance:

6. Faulty Wiring or Connections

Faulty wiring and connections are an easy way for electricity to escape, causing corrosion damage along the way. This includes dirty terminals, which need regular cleaning whenever possible.

Corrosion due to poor wiring usually occurs near the area where the positive and negative cables connect to the battery itself. It’s best to check this whenever you feel your car battery has issues.

How To Fix

Take care of the corrosion by wiping down any dirty terminals. Place a mixture of baking soda and water on dirty areas and let sit for 5-10 minutes, depending on how bad the damage is. The grime should then wipe away with a paper towel or cloth. If that doesn’t work, sandpaper or tin foil can also do the trick.

Replacing wirings like corroded cables, connectors, fuses, and relays is sometimes necessary. Still, it’s best to take your car to an auto electrician if you don’t want to risk doing any damage yourself. Furthermore, they may recommend getting new alternators if they notice something is also wrong with them. In general, it’s a good idea to ask about this if you go to a mechanic.

7. Contamination From Acid or Water

Another cause of corrosion to car batteries is contamination from acid or water. This mainly happens when the battery is exposed to either for too long, corroding its internal components.

When acid comes into contact with the negative plates, it forms hydrogen, an explosive gas that can cause problems.

It’s important to keep your battery away from moisture as much as possible. If water gets inside your battery, minerals and other contaminants will build up and disintegrate the plates over time. This can cause shorts and corrode your wiring.

How To Fix

You can prevent this by always keeping batteries in well-ventilated areas to avoid overheating. Also, take caution not to spill any fluids on the battery or inside the vents.

Additionally, wipe off any dry corrosive substances present on the battery’s exterior as often as possible. This includes dust, dirt, grime, road salt, and other contaminants.

Another way of preventing contamination is using distilled water instead of tap water. Hard water, in particular, contains minerals that damage your car’s electrical system over time.

A good rule of thumb is to check your battery every 6 months for the signs of corrosion or damage. Doing so will help you know in advance if the battery needs to be replaced.

Finally, have your car’s electrical system checked regularly to verify everything works properly, especially when there are issues with the alternator, starter, and ignition, which are all connected.

8. The Battery Is Too Old

If you’ve had your car for several years without replacing the batteries, it’s likely the battery isn’t working as well as when it was new. Batteries usually start to go bad after about 4-5 years, sometimes earlier if not properly maintained for this period.

As your car battery ages, it starts to lose its ability to hold a charge, and the amount of power it can generate reduces significantly. In addition, the electrolytes inside the battery can get diluted, causing more problems.

Here are the common signs your car battery is too old:

  • The exterior casing is bulging, swollen, or rusted. This can be a sign it’s about to burst open or explode under pressure, so you shouldn’t ignore it.
  • Your car has a slow crank and doesn’t fire up right away when you turn the key in the ignition. This means the battery isn’t providing enough power to get your engine going, which can be dangerous if left unattended for too long.
  • The terminals on the battery are corroded or have dark brown, blue, or green residue. This is usually caused by corrosion and buildup from leaking electrolytes over time which will damage components like alternators and starters, so it’s crucial to fix this problem as soon as possible before things get worse.

How To Fix

If your car battery doesn’t work properly or shows signs of corrosion, it’s best to replace it with a new one that can hold a charge longer and provide sufficient power for the ignition to work.

Note: Even if no corrosion has occurred, you should switch out the battery if it’s more than 4-5 years old.

9. The Battery Is Overfilled

Another common cause of car battery problems is filling it with too much distilled water, leading to more electrical resistance inside the battery. This causes it to overheat, which leads to more spilling, gassing, and contamination with acid or water. If you have a car with loose caps on top of the battery, be sure to keep an eye out for these signs.

In addition, overfilling the battery with distilled water can cause it to swell, causing the battery tray or casing to crack. This is another sign that electrolytes are spilling out, which will damage sensitive electronic components if not resolved immediately.

How To Fix

The best way to prevent overfilling is constantly checking your owner’s manual for these specific guidelines when adding distilled water after charging the battery using a hydrometer. If the battery is too swollen or bulging, this would be another reason to get a new one, as a swollen battery will eventually explode under extreme pressure.

10. An Electrolyte Leak

As mentioned before, car batteries are made up of numerous cells arranged in a series to generate power for your car’s electrical system while holding a charge.

The last thing you want is any of these cells corroding and causing leaks. Once that happens, things can get ugly real quick, and you can expect an explosion if you don’t fix the problem immediately.

How To Fix

One of the best ways to fix an electrolyte leak is with non-conductive dielectric grease, which can be found online or at your local hardware store. If you don’t have any on hand, a generous layer of petroleum jelly works just as well for this purpose.

This will prevent the corrosion from spreading and causing more leaks, so it’s essential to fix any existing problems immediately before it’s too late.

Note: If the corrosion is already present, you must first clean it and check for any loose wires or cables touching each other before applying dielectric grease (or petroleum jelly) on top.

Final Thoughts

A car battery is an essential part of your vehicle, powering your lights and ignition while you’re driving. However, it doesn’t last forever!

Eventually, you’ll be faced with a corroded or damaged battery. By being aware of the common causes for these problems in advance, you can prevent them from happening by taking easy steps toward proper maintenance.

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