Distilled Water for Batteries (How It Works And Why)

You wouldn’t have imagined how well these two things work together. You might have heard this trick from mechanics and technicians about bringing a dead car battery (and even large lead batteries) back to life again with some distilled water. Although the trick itself doesn’t fully revive the battery, the trick gives it a second wind that will get the job done in most cases?

This trick is especially useful with cars, which depend on batteries to get the engine running as well as other functions. Imagine getting stuck in the middle of the highway with a dead battery.

Although these things are meant to last for very long periods of time, regular use and abuse as well as wear and tear will eventually shorten the expected lifespan of your battery.

One way to circumvent this problem is to use distilled water for battery units. It lengthens the battery life and improves performance and efficiency. One interesting thing to note is that using regular tap water does little to help your battery. At most, it even contributes to damaging your battery and decreasing its life span.

The Deal with Batteries

The reason behind this trick lies in the way batteries operate. In order to understand the mechanics of the distilled water trick, it’s important to understand how a battery works.

A battery, when broken down will yield three major portions from which it draws out electrical currents. These are:

  • separator
  • electrodes
  • electrolyte

These three components work together to create a chemical reaction that releases an electric current from the battery.

Different car batteries can use a variety of chemical combinations to generate this electric current. One of the most common combinations is lead dioxide and lead.

Here’s what happens inside a battery:

  • When the battery is connected to your car and you attempt to start it, the lead dioxide and the lead sponge in the battery react to form a new compound known as lead sulfate.
  • During this process of creating the new chemical, electrons are released from the two initial substances. When the car is started, the electrons flow through the electrodes of the battery and into the electrical system of the car, providing the necessary voltage to get things going.
releases an electric current from the battery


  • Water plays an important part in this chemical process. When the initial chemical reaction takes place within the battery, the newly-created electrons would need a medium in which to travel from the inside of the battery to the electrodes which will carry the current into the car.
  • This is where water comes in. The water will serve and the medium for the electrons and ensures that all of the stored electrons in the battery get used properly.

It is important to note, though, that as the water in the battery helps conduct the electrical current away from the inside of the battery, the water is also subjected to the chemical process that creates the electrons in the first place.

This causes the water to go through changes as well. Usually, this change causes the water to evaporate, depleting the amount of water in the battery. With less water in the battery to carry the electric current, the battery doesn’t perform as well as it should.

This is the reason why car owners would usually replenish the amount of water in their batteries by using tap water.

The problem with tap water

Although tap water replenishes the battery and keeps it up and running, it also contributes to its wear and tear. Certain substances in the water affect the chemical processes that are already running inside the batter.

 water treatment facility


Water that comes from faucets and other home sources is laden with minerals. These could be minerals coming from the home plumbing system as well as the local water treatment facility in the area. This kind of water can slow down your car battery’s performance over time.

This is because the minerals in the water get left behind after it evaporates from inside the battery.

When the water evaporates, mineral traces such as iron and calcium don’t evaporate with the water. They get left inside the car battery.

When this happens, these minerals attract the free-flowing electrons that should have been used by the car. What happens is that these electrons attach themselves to the minerals and create a different compound which has no place inside the battery.

This, in turn, will cause the battery to lose out on efficiency because of a lack of electrons. It also shortens the lifespan of the battery because of the mineral build-up that takes place inside the car.

Enter distilled Water for batteries

On the other hand, distilled water doesn’t carry the same problem as tap water. This is because distilled water doesn’t carry enough substances to affect the battery. It’s pure enough and does not affect the chemical processes that need to take place inside the car.

evaporates inside the battery


When distilled water evaporates inside the battery, it doesn’t leave anything behind. Every other contaminant in the water evaporates as well, leaving nothing significant but water vapor. That means there won’t be any minerals to affect the chemical processes inside the battery.

What you get is an efficient battery that will start your car without fail. You’re also left with a healthy battery that doesn’t deteriorate as much as a battery that’s topped off with tap water.

Another reason that distilled water is better for car batteries is because it’s acidic. You might be wondering why something as harmless as water could be classified as acidic. This is because of the distillation process.

When water is distilled, it turns into water vapor then is condensed back into a liquid state. During this process, carbon dioxide from the immediate area gets dissolved in the water. This creates a very weak carbon acid solution.

Is distilled water acidic and dangerous?

This is because the level of acidity within distilled water is very low. To answer the question “Is distilled water acidic or alkaline?”, you need to would measure its acidity through a pH scale.

the level of acidity within distilled water


Distilled water comes around a level of 6, which is very close to the neutral level of 7 on the pH scale. This scale goes from 1 to 14, where any value below 7 is acidic and any level above 7 is considered as alkaline.

When drinking distilled water, our bodies counteract the acidity of the water by having our stomach produce more stomach acids to deal with the water. As long as you keep a healthy stomach, you’ll be able to handle drinking distilled water on a regular basis.

Because your car batteries operate on a chemical process, distilled water helps this process happen because of its slightly acidic properties.

It helps break down the lead components better which makes for a more conducive area for these chemical processes. This makes distilled water a great alternative to tap water for your car battery.

Where to buy distilled water for batteries?

Although it’s slightly more costly than tap water, distilled water can be bought at supermarkets and grocery stores. They are usually sold in bottles and come in different brands. Having a few bottles at hand in the glove compartment is a good idea just in case your car has problems starting up.

bottled distilled water in groceries


You can buy bottled distilled water in groceries.

Little do people know that a car needs about 12 volts in order to get started once you turn the key. After that initial charge, a steady current has to be kept in order to keep the electrical systems of the car running smoothly.

That means the battery needs a constant supply of water in order to operate properly. Interestingly, this is also the reason why a dead battery is also called a “dry battery.” This isn’t because the battery has run out of electrons. It’s because the battery has run out of water.

Just be careful to read the labels on your bottles before purchasing them. There’s a large chance that your grocery store sells distilled water right next to their mineral water selections as well.

As you’ve already learned, foreign minerals inside your car battery aren’t a good idea. Make sure that you’re not buying mineral water.

How to make distilled water for batteries

On another note, you can also create your own distilled water through the process of distillation. In a nutshell, distillation simply entails the usage of a heating system to get the water to evaporate at different temperatures.

When the water evaporates, it turns into water vapor. Since heavy metals and other minerals cannot evaporate with water, they get left behind by the water vapor. What you get at that point is distilled water vapor.

a matter of condensation or cooling


After heating the water and turning it into vapor, it’s simply a matter of condensation or cooling. Putting the water vapor through lowered temperatures will bring the vapor back to a liquid form, leaving all the heavy contaminants behind.

You can either create a DIY water distillation system on your own with special materials as well as a heating system like a stove. There are plenty guides on the internet that will show you how to set up a working system for your personal use.

Be warned that an amateur may find it difficult to set up a distillation system. In fact, it can become quite dangerous. Be sure to ask someone for help and exercise every precaution. You undertake this project at your own risk.

Interestingly, you can also buy a water distillation system from many manufacturers. These can be installed into your home water system to ensure that the water that you use around the house is free of heavy minerals and other contaminants.

Are you prepared?

For the more practical readers, you may think that this is too much trouble. But when power is out and you have an emergency, this distilled water-battery system may be exactly what you need. Don’t discount science at all.

You may never know, but if The Walking Dead comes true, this is one of the most important information you could have, right?


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