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Are Car Batteries Waterproof?


Waterproof car batteries – now that’s a topic that’ll get people talking! Seriously though, this is a vital question for a lot of drivers. You don’t want your battery to die in the middle of a rainstorm, do you? So, are car batteries waterproof? 

A water-resistant casing protects car batteries and generally keeps water off the internal components. But while car batteries are water-resistant, they’re not waterproof.

Continuous exposure to wet conditions can lead to dampness and moisture buildup, which can easily corrode the car battery terminals.

How are Car Batteries Water-resistant?

Contrary to popular belief, car batteries are not waterproof but water-resistant. When you pour water on a car battery, it will bead up and roll off. This is because a polypropylene resin covers the surface of the battery and repels water off your car battery surface.

The water-resistant properties are, however, dependent on the brand and type of car battery you have. 

For example, sealed car batteries won’t let anything into the internal components, while vented car batteries can, in some instances, let water seep in.

The takeaway point is that if your car battery’s integrity isn’t compromised, it should be water-resistant.

Components of a Car Battery Prone to Water Damage

A typical car battery comprises various components, but these three are the most prone to water damage:

Battery terminals

Even if you don’t know a lot about batteries, you probably know they need to stay dry. That’s because when battery terminals come into contact with moisture, they can get corroded, affecting optimal current flow.

Battery lid

The lid you use when you top up your car battery water is also highly susceptible to water damage. Be sure to check the lid regularly for cracks, and if you find any, replace it immediately to prevent internal components damage when the battery comes into exposure to wet conditions.

Battery wires

While it’s common to think that only the above car battery components are prone to damage, battery wires are also a culprit. If the wires connected to your car battery come into contact with water, they trickle charge, which can add up to a significant discharge in the long run.

Is it Bad for a Car Battery to Get Wet?

Generally, there’s no major risk of a wet battery, as most of the moisture will stay off the components thanks to the waterproof casing. The problem arises when the wet conditions are long-lived since they can corrode the battery terminals.

It’s also worth noting that there’s a potential for an electrical shock if you connect two wet car battery terminals.

What to do When a Car Battery Gets Wet

It’s essential to keep your car battery dry, especially in rainy or snowy weather. But, when water gets to your car battery, you should dry the outer casing with a towel or rad if there’s still some water residue on it. 

Typically, most of the water should roll off the casing almost immediately. If the water gets to the battery terminals, pad them off with a dry towel and only use the battery when the terminals are completely dry. 

If your battery terminals get corroded by the wet conditions, here’s what to do:

  • Pour some baking soda to give each terminal a nice coating. 

  • Pour a small amount of water into each baking-soda coated terminal.

  • Leave the two ingredients to react to each other and neutralize the corrosion.
  • Wipe down the terminals with a dry towel before use

Tip: If you’re not sure whether to use your car battery when it gets wet, take it to an auto car parts expert and have it checked.

Can you Charge a Car Battery in the Rain?

Most electric vehicle batteries come with heavy insulation, and you can charge them in the rain safely. However, leaving your car battery charger out in the rain is not advisable as you’re risking damaging it. 

The plug, extension cord as well as circuit board making the electric car battery charger are prone to damage and could pose a danger if left in wet conditions. 

What Happens When a Car Battery Gets Submerged in Water?

If the sealant holds up well and keeps moisture from seeping into the battery, it’ll continue working as usual. But if the sealant lets water seep into the battery, it can dilute the electrolyte and damage internal components. 

If water seeps into your battery, consider swapping the electrolyte or replacing the battery altogether. 

Despite the battery housing acting as an insulator, a slow discharge may also happen if water accumulates on the battery terminals. Lastly, if rusting occurs, it can slowly break down your car battery to a point where it may not be suitable for use in your car.

Please note: Although both freshwater and saltwater affect a car battery, in the same manner, the latter may be more detrimental as the salt molecules ramp up the rate of discharge from your submerged battery.

So, unless it’s an accident, you should never submerge your car battery in water. If you’re not planning to use your car battery any time soon, consider storing it in a battery box to keep it dry at all times.

Is it Safe to Jumpstart a Wet Car Battery?

According to auto experts, vehicle voltage is not high enough, so jumpstarting a car in wet conditions is safe. 

However, you need to jumpstart your car in the correct sequence and ensure that there are no water drips on the cables to avoid electrical shock.


Are car batteries waterproof?

In a word, no. Car batteries are not waterproof, and if they get exposed to wet conditions for long, they can get corroded and, in some instances, slowly discharged.

That said, though, as long as your car battery housing and lid are intact and in pristine conditions, there’s no need to worry about your battery getting wet. That’s not to mean that you should leave your car battery out in the rain or damp conditions, as that could add up to problems.

If anything, you need to keep your car battery in a dry place that is free of moisture.

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