DIY: Battery Reconditioning

Updated February 21, 2017

Car batteries are not cheap. They also do not last forever. It is much less expensive to recondition a battery than to purchase a new one every time something goes wrong with one. The battery needs to be reconditioned because it has become sulfated over time. This causes the battery to hold less of a charge and lengthens the amount of time it takes to recharge. Reconditioning reverses this process.

Heat a quart of distilled water to 65.6 degrees C.

Mix 10 spoonfuls of Epsom salt---magnesium sulphate---into the warmed water. Stir the mixture until the salt is completely dissolved.

Uncap your battery with a screwdriver to expose the cells. Take your flashlight and inspect the cells to determine if there is any water in them. If there is water in the cells, you will have to turn the battery over to drain the water out.

Insert the plastic funnel into one of the cells and slowly pour the solution into it. Ensure that you do not overfill the cell. You will see a fill line that is 1/2 inch below cell's top. Do not fill past this line. Repeat this process for each cell. Recap the cells after you are done filling them.

Shake the battery with the caps on to completely mix the solution within the cells.

Pull the caps off the battery and attach it to a trickle charger. Charge the battery for at least 24 hours before using.


Exercise extreme caution when removing the fluid from the battery. This fluid contains concentrated acid.

Things You'll Need

  • Epsom salt
  • Quart of distilled water
  • Car battery
  • Screwdriver
  • Trickle battery charger
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About the Author

Jay Angel has been a writer since 1998, specializing in scientific writing, as well as articles about fishing and hunting. He worked as a columnist for the Illinois newspapers, "Daily Chronicle" and "News Tribune." Angel has a Master of Science in fluvial geomorphology from Northern Illinois University.