Can we use RO water in the inverter battery? (Distilled vs. RO water)

By Matthew Joseph Nandirio •  Updated: 09/23/21 •  5 min read

Inverter battery is the most important part of your home inverter. Therefore, it is crucial to maintain it with proper guidance to enhance its durability and function. Moreover, it also increases the self-life of the battery and gets you maximum of your investment.

So, when you buy a battery, the first maintenance step is to water it when necessary. It is almost like a human body mechanism. The water helps to remove the metals and minerals that might interface the process of the battery.

When you pour the water, it is converted into oxygen and hydrogen through a chemical reaction. Therefore, based on the usage, the water gets evaporated quickly.

Is RO water suitable for inverter batteries?

Let me first tell you, what is RO water? And what does it contain? Basically, RO or Reverse Osmosis is a process of filtration. In this process, the water forces through multiple layers of membranes to purify the water. Therefore, it is indeed a great choice as drinking water.

However, when it comes to the matter of batteries, distilled water is always a better option.

The RO technique eliminated the unwanted salts, iron, and other impurities from the water.

Naturally, the TDS and PH levels go down, which is beneficial for the human body. In contrast, the same level of water hardness might compromise the function of your battery. So, as long as PH and TDS level is acceptable as per the recommended measurement, there is no harm in using RO water.

The ideal choice of water for batteries

Water generally contributes to the performance of the battery. As per the researchers’ instructions and from my personal experience, I would recommend distilled water for batteries. Let me explain why distilled water is best for batteries.

  • The water used for the battery should be demineralized with an electrical conductivity of around 10-5 ohm. On the other hand, the PH level should be around 5 to 7.
  • Three major water compounds like Chlorine, Nitrogen, and sulfur, should be distributed in the water proportion. Similarly, the metal ions with H2S or NH4 should be less than the detected water compounds.
  • Moreover, the water impurities should range below 20mg/L.

So, if all these conditions are present in particular water, it can be considered an ‘ideal’ choice for the battery. On the other hand, the potential of oxygen and hydrogen evaluation might distract the function of the battery. It can also hinder the efficiency of the machine.

If you want better battery life, these specified ranges should be maintained. Hence, we have to ensure that the water is not impure or mineralized.

Can boiled water be used in inverter batteries?

 Water boiling is a process to eliminate surplus salts, minerals, and impurities. The presence of minerals fills the pores and layers of the plates and obstructs the electrochemical reaction. Interestingly, this reaction creates energy or power in the battery. So, you see, it is fundamental for the battery to generate power. I hope you will help the battery to produce the power.

Similarly, the chemicals present in the water base can decrease the lifespan of the battery. Tap filtering water never eliminates these chemical compounds. Rather, boiling water does. Boiling water has no dissolved minerals, inorganic, or organic compounds. If you want to enhance the function and durability of your battery, I would recommend using distilled water.

Distilled water Vs. RO water

In ideal conditions, distilled water is always a better choice for your batteries. However, what if you don’t have distilled water nearby! Using RO water for an alternative a couple of times is fine! However, choosing RO water as a regular use for your battery is not at all fine!

What matters the most in terms of water used for batteries? It is the PH and TDS levels. Good distilled water contains both. On the other hand, RO water doesn’t meet the requirement of a battery. It generally doesn’t harm your battery, but it doesn’t enhance its performance.

However, distilled water is available in the market that lacks a TDS level and exceeds 25 PPM. Both this condition is unsafe for the lead of the batteries. So, it is better to check the components and level of TDS and PPM before using them.

Why should you use distilled water for inverter batteries?

Distillation is the process of boiling. It helps to capture the condensation and remove all the impurities from the water. The boiling process removes the microbes but is unable to discharge the chemicals and minerals. However, distillation is a scientific process where the PH level and TDS level is closely maintained.

Distilled water is free from all unnecessary impurities and chemicals that reduce the performance of the battery. Inverter battery produces power and energy, and water should help in generating the power. Distilled water does the same. It has no dissolved minerals, salts, or in-organic products. As a result, inverter battery manufacturers always recommend using distilled water for better durability.

Bottom line

As far as the lifespan of your battery is concerned, I would recommend you to use distilled water. From recent research, the most renowned batter companies suggest using distilled water.

When you fill your inverter battery with hard water, it is likely to recommend avoiding tap water.

Similarly, RO water is not an ideal option for battery and its performance. Moreover, if you continue with hard water every time, it will die soon. Use RO purified water only in case of emergency. For regular use, there is no better replacement of distilled water for inverter batteries.

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Matthew Joseph Nandirio

Matthew Joseph Nandirio is the Founder of walkingsolar. After graduating from the University of Houston in 2002, matt started working as an electrical and electronic engineer for several multi-national solar energy companies. He has a wide range of experiences including solar system requirement analysis, planning, maintaining, debugging and even solar device development through research. He now shares his 20 years of expertise through his articles on the walkingsolar website. Further, he is also the author of two books on Solar Technology, “Solar Power for Villages” and “DIY Solar System for Dummies”.