To refurbish an old car battery, wash the outside, remove the cell covers, refill the cells with distilled water, and charge the battery. The process should take no more than one hour. Working with car batteries can be dangerous, so use caution when performing this task.
- Wash the battery
Using a mixture of water and baking soda, clean off the outside of the battery. Wear protective gloves and eyewear to prevent contact with any loose acid.
- Remove the battery cell covers
Most batteries have two small plastic caps that cover the six cell holes. Remove these caps, and place them aside. Carefully remove any dirt or debris from the areas that were previously covered by the caps. It is important that no dirt falls into the cells.
- Refill the cells
Using distilled water, refill all of the cells up to about 1 inch from the top. Do not use tap water, as it contains minerals that can ruin the inside of your battery through corrosion. Once all of the cells are filled, replace the caps.
- Charge the battery
Cycle the battery through multiple charges. On a conventional charger, it may take a number of cycles to fully restore the battery.