In the process of battery charging some of the water molecules disintegrate into hydrogen and oxygen. Some of these are able to get out of the battery. Hence, the repercussions are:
- Acid is hyper-concentrated.
- Due to less liquid, the lead-plates may not be fully dipped into it.
Hence, capacity of the battery to hold current is compromised to some extent.
Now, to resolve the situation we need to do two things:
- Make up the reduced level of electrolytic liquid
- Dilute the hyper-concentrated acid
Adding distilled water is the solution to this.
Now, if tap water is added to the battery, various salts dissolved into it would also be added to the battery. And, these salts would neutralise the acid and also interfere with oxides into lead plates. This would deteriorate the battery system and the performance would be compromised.
To avoid the situation, we need to top-up the battery electrolyte with distilled water only.