I goofed.

Topping up the car battery I accidentally poured mineral water instead of distilled. The charge indicator shows between 1.5 - 2 Amps

Have I managed to place the battery in jeopardy? What precaution/s should I take?

  • Why do you need to add water to a auto battery ? I have not done so in decades. If the water is low , most likely it is being overcharged. Dec 2, 2018 at 22:57

2 Answers 2


"Mineral water", for this purpose, is equivalent to using tap water. It won't immediately destroy the battery, but you are disturbing the chemistry by adding some kind which don't belong there. You may have shortened the battery's life a bit.

But there isn't much you can do about it now short of draining and replacing the battery acid, and I don't think that's worth the effort. Just try not to do it again.

  • 1
    +1 The amount of mineral water is likely to be a relatively small proportion of the total liquid volume, so this sounds right.
    – bib
    Oct 5, 2016 at 11:44
  • "try not to do it again" makes me feel like I'm a 6-year old at school again ...
    – Everyone
    Oct 8, 2016 at 15:03

The acid in the battery has attacked the minerals in the water, essentially neutralizing a proportionate amount of acid and leaving some salts in the bottom of the battery. It is probably a negligible amount, and won't affect capacity or lifetime if you do it once. Making a habit of it will shorten battery life, yes.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .