How To Refurbish A Car Battery?. If your car battery is not functioning at optimum because it has a dead cell inside, you can indeed restore it instead of getting rid of the whole battery owing to safety concerns.
- If your battery is a 12-volt one, a voltmeter should show a reading of 13 or more volts immediately after a complete charge session. If the value is only around 12.5 volts, then charging was not optimal and you could have a dead cell problem.
- Empty the acid vents half way following all the right procedures for safety (emptying into a bucket of baking soda and water solution to neutralize the acid).
- Pour a blend of Epsom salts (1½ cups) and hot distilled water (2 cups) into the vent holes. This technique may serve you for about 3-4 days and the problem will return.
- Perform this process to determine which cell is dead. The gaseous nature of this process will result in bubbling at each vent except for, you would have guessed it, the dead cell.
- Discharge the battery using a fog light and start charging it afterwards at about 3 or 4 amps. Your aim is to revive that dead cell gradually. It will show signs of bubbling after, say, two hours in a cold clime; time will vary.
- Repeat this entire process of discharging and charging under the influence of Epsom salt solution. Do it thrice in total over the course of a few days.
- The dead cell will eventually come back to life and bubble as well as the other active cells. This entire process depends on the Epsom salts to get the job done over time. Otherwise, the voltmeter will show a mediocre voltage capacity and the battery will not function at its optimum.
- Once off the charger, the voltmeter’s value will gradually drop and the dead cell in question may cease to bubble while the other live cells continue to do so.
- You can use the red or positive cable coming out of the voltmeter device, dip the metal end in each briny cell cavity and check the voltage. The dead cell will show about half a volt, which is normal after one session of the above-detailed process. Other cells will have voltages that vary between 1 and 12 or 13 volts.
If you do not have Epsom salts or access to distilled water, the required amount will cost you around $2 each at a department store. If you have the patience for the job, you could completely restore a dead cell in an otherwise good battery.