How To Check Vehicle Battery Electrolyte Levels

Your vehicle's battery operates many electrical systems, so it needs the correct fluid or electrolyte levels. The electrolytes help the vehicle store the energy to be used by the battery.

The 'wet cell' is made from water and sulfuric acid that joins the electrodes of each cell. Check your vehicle battery electrolyte levels using this guide:

Prepare to Check the Electrolytes

To check the electrolyte levels, gather:

  • old work gloves
  • eye goggles
  • shop rags
  • disposable cup
  • old toothbrush
  • baking soda
  • distilled water 
  • wrench set (optional)
  • putty knife or flat-blade screwdriver 

Wear closed-toe shoes, old pants, and a long-sleeved shirt since battery fluids can cause holes in fabric. If your skin accidentally gets splattered with fluid, wash it under water immediately. Discard all rags, gloves, and tools you use to fix the battery.

Open the hood, and prop it to access the battery. Batteries are commonly black boxes located around the front tires, front bumper, or motor compartment. In some sports models, the battery may be installed in the trunk or below the back seat.

Clean the Battery

In some cases, you may find it easier to remove the vehicle's battery for easier access. To remove the battery, use the correct type of wrench to remove the clamp bolt holding the negative cable, then detach the other clamp. If there is a bracket or housing, unscrew the nuts by hand, and set pats aside.

Pour one-fourth cup of baking soda in a disposable cup, and add water until thick paste forms. Use the old toothbrush to spread the mixture on the battery terminals and clamps.

Open the battery port covers with a flat-blade screwdriver or putty knife, or twist round port covers off by hand. Clean the ports with a damp rag.

Check the Electrolyte Levels

The inside of the battery ports should contain the same amount of fluid. Look inside the ports to check the levels, using a flashlight, if needed. Sometimes, overfilling can cause low levels or a leak. 

Average fluid levels come to one-half inch over the plate tops, and an eighth-inch under the tube bottom. Maximum fluid levels come just under the filler tube bottom, which is commonly indicated by the meniscus (liquid that bends near the tube edge) forming an eye-shape on the slots. If the cells look to be normal, filing them isn't needed, but check periodically. 

Fill them with distilled water according to the condition. If the battery is fully charged and new, add water until it comes to the bottom of the filler tube until the eye-shape forms. For old batteries, add enough water to cover electrodes. Reinstall the battery and the port covers. Contact a company like Joy  Automotive Products Inc for more information and assistance.