Why Distilled Water is Used in Battery?

Distilled water is used in batteries, specifically flooded lead-acid types, primarily because it is free from additional minerals you would find in water such as regular tap water. This purity is crucial for maintaining battery health and performance.

Avoiding Harmful Contaminants

The electrolyte in a flooded deep cycle battery is a solution of acid and water. Over time, especially during charging, the water component of the electrolyte can evaporate, necessitating periodic topping up. However, not all water is suitable for this purpose.

Regular tap water contains various minerals, salts, and chemicals such as calcium, magnesium, iron, and chlorine. While harmless to drink, these impurities can react negatively with the materials inside a battery.

The Impact of Impurities

Introducing minerals and chemicals into the battery's electrolyte can lead to several problems:

• Unwanted Chemical Reactions: Minerals can participate in side reactions that interfere with the battery's intended electrochemical processes.
• Plate Contamination: Impurities can deposit on the lead plates, hindering the flow of current and reducing the battery's capacity and efficiency.
• Increased Self-Discharge: Contaminants can create conductive paths between the battery plates, causing the battery to lose charge more quickly when not in use.
• Ultimately, as highlighted by the reference, adding chemicals and minerals can significantly decrease the life of batteries.

The Benefit of Distilled Water

Using distilled or deionized water ensures that you are adding only pure H₂O to the battery. This maintains the integrity of the electrolyte solution and prevents the introduction of damaging substances.

Here's a simple comparison:

By choosing distilled water, battery owners help prevent internal damage, maintain the battery's charge capacity, and extend its overall service life.