It’s sometimes referred to as battery acid because it’s highly acidic.
In fact, the battery electrolyte is made from a mixture of water and sulfuric acid.
Do not do this.
Jan Stromme / Getty
Never put any kind of electrolyte in a lead-acid car battery.
If your battery electrolyte is low, the only thing you should ever add is straight water.
What Does it Mean When Battery Electrolyte is Low?
What does that mean?
Car batteries are composed of a series of lead plates submerged in a bath of water and sulfuric acid.
This creates a chemical reaction that builds up electrons, which eventually discharge in the form of electrical current.
Sulfation can shorten the life of a battery because it interferes with the normal operation of the cells.
It is then released back into the electrolyte solution as the battery charges.
Adding anything but water to a battery can instantly damage it, but some substances are worse than others.
For example, baking soda can neutralize the sulfuric acid present in a battery’s electrolyte solution.
If it is not fully charged, the battery will overflow as it powers up and cause damage.
How Can Water Be an Electrolyte?
Water, on its own, is not an electrolyte.
An easy way to understand how this works is to think about boiling a pot of saltwater.
The water evaporates, but the salt remains behind.
The same thing happens when you add distilled water to a lead-acid battery.
The only exception is if the fluid is low due to the battery tipping over.
When that happens, the entire solution of sulfuric acid and water is lost.
In that case, you better fill the empty cells with a dilute mixture of water and sulfuric acid.
Once a battery reaches a certain tipping point, there’s no coming back.
