Learning how to safely check the electrolyte levels in your car battery is an important aspect of car maintenance that should be performed a few times each year. Checking is important for two reasons: first, because electrolyte naturally...
Now that the cells are open you will want to check the level of the electrolyte. The best way to tell if the battery needs more electrolyte is if the plates are exposed or coming close to exposure. Another way to tell is if the electrolyte levels are not equal in each cell. In this case, electrolyte simply means distilled water.
IMPORTANT: Make sure the battery is clean, fully charged, and is at room temperature. Squeeze the hydrometer rubber bulb and submerge the tip into the electrolyte of the first battery cell you're testing. Release the rubber bulb to draw a sample of electrolyte into the hydrometer. NOTE: Make sure to draw enough electrolyte into the hydrometer.
Draw a full sample of electrolyte into the hydrometer. The float should float freely in the liquid. The reading where the electrolyte meets the scale on the float shows the electrolyte density. Carefully empty the electrolyte back into the battery. Put the cell cap back on. i Be sure to disconnect the battery terminals.
As the battery discharges, the sulfuric acid reacts with the lead plates to produce lead sulfate and water. This reaction reduces the specific gravity of the electrolyte solution. By measuring the specific gravity of the electrolyte solution, a hydrometer battery tester can determine the state of charge of the battery.
i Check the electrolyte level of every cell. Park the car on a flat surface. Clean the battery cells of dust and dirt. Remove the cap of the cell and insert the tube. When the tube reaches the lead plates, fill it up and take it out. Put the cell cap back on. The height of the electrolyte in the tube indicates its level in the battery.