If you decide to refill the acid in your car battery, you might not need to buy a new battery. Extra acid will increase the lifespan of the battery and will save you some money.

However, working with acid is dangerous, so you have to take all safety measures. You should always wear protective equipment and you should only work in an aired room on a safe surface.

Here is how to refill the acid in car battery in a safe manner:

  • Wear some heavy gloves, a pair of goggles, and a face mask. This is very important because the acid can damage your skin instantly. More than that, the fumes from it can irritate your eyes and your respiratory tract.
  • Prepare a solution of 75% water and 25% sulfuric acid. Do this in an aired room and only use a glass container for the solution. First, add the water and then gradually mix the acid in it while stirring. Do not put the acid first.
  • Take the car battery out and put it on a stone surface. Concrete will not do the job. Use a water and baking soda solution to wash the battery and then let it dry.
  • Use a flathead screwdriver to take off the caps from the top of the battery. Do not put your hands on the parts of the caps, which were in direct contact with the acid.
  • Use a flashlight to see how much acid is in the battery and slowly refill its level with the solution you have just prepared. Pour solution until you reach the rim of the battery cells.
  • Put the caps back on. Make sure they correctly fit back and use a hammer if necessary.
  • Put the battery back in the car and start reconnecting it with the negative terminal. Start the car and drive it for half an hour in order to charge the battery.
  •  Take off the clothes you used in refilling the acid, wash them carefully, and take a shower even though you were not in direct contact with the acid.