Motor Expo 2026

Have you ever wondered how drinking water and pure distilled water differ in cleanliness? This leads to the question: "Can drinking water be used to refill batteries instead of distilled water ? Let's look at the answer in the following article.

"Can drinking water be used to refill batteries instead of distilled water?" The author says

No, it's not true, or rather, it cannot be done. Because water for refilling batteries merely being clean is not enough. It must be pure and contain no minerals.

Water that can be added to batteries must not contain any minerals. If it does, it must not exceed the criteria set by the manufacturer for use. Therefore, it is necessary to use only “distilled water” produced for refilling batteries. As for drinking water, it contains many minerals that negatively affect the lifespan, voltage, and efficiency of the battery.  

There may be some groups of people who believe that “drinking water” can be used instead. Let's understand this issue.

The water in the battery is “acidic water”. Its volume will continuously decrease due to chemical reactions with the lead plates. Some parts will evaporate into hydrogen and oxygen in the form of water vapor. The remaining water is therefore highly concentrated and very dangerous acid (do not touch under any circumstances). Therefore, if it runs low, water must be added to replace the evaporated portion. But water that can be added to batteries “must not” contain minerals. If it does, it must not exceed the criteria set by the manufacturer. For example, calcium must not exceed 40 parts per million (PPM), magnesium must not exceed 40 parts per million (PPM), or nitrate must not exceed 10 parts per million (PPM), etc. If these minerals are present in excessive amounts, the battery's performance will not meet the full specifications set by the manufacturer. Therefore, only “distilled water” produced for refilling batteries must be used. 

If we use drinking water, we will inevitably encounter many minerals exceeding the specified criteria. This can negatively affect the lifespan, voltage, and efficiency of the battery. The concern is the distilled water widely sold in our country; we don't know if it's “genuine” distilled water (Distilled water is water that evaporates into vapor when heated. Impurities in the water do not evaporate with it, making it clear, pure, and clean) or just ordinary filtered water. The Office of the Consumer Protection Board (OCPB) should conduct a thorough investigation.   

Furthermore, nowadays, some distilled water is being “colored” and advertised with numerous properties, sold at almost double the price of regular distilled water. In reality, this type of colored distilled water offers nothing special beyond clear distilled water. Our technical editor once said that colored distilled water is like pickled guava or prawn crackers; they look good but don't provide any additional nutrients. “Distilled water” must be clear and pure only. If it has “color,” that is simply an undesirable foreign substance (Contamination).

Article by : Witthawin Traiphit  

Column : Is it true what they say?

Magazine "FORMULA" September 2016 issue