How to Rejuvenate an Old SLA Battery With EDTA

A lead acid battery is, most commonly, a 12 volt battery with a series of six cells. Each cell contains a positive lead oxide plate and a negative lead plate and is filled with a solution of sulphuric acid. As the battery is used, the positive plate reacts with the sulphuric acid and produces lead ions in the water. The lead ions combine with the sulphate ions in the sulphuric acid to form lead sulphate. As the lead sulphate coats the plates, the battery is less effective and will eventually fail. Treating the battery with an acid called EDTA will remove the sulphating and prevent future sulphating.

Things You will Need:

  • Ethylenediaminetetraacetic acid (EDTA)
  • Teaspoon


  1. For an average sized battery, dissolve 30g (6 teaspoons) EDTA in deionised water. (5g for each cell)
  2. Add this solution equally to each cell.
  3. Agitate the battery frequently for the next couple of days and use the vehicle regularly. Do not charge the battery completely during this time.
  4. Charge the battery thoroughly after a couple of days. You should see increased performance from this point on, as the EDTA frees the plates of lead sulphate that has been coating the plates.


  • Do not try to dissolve the EDTA directly in the battery acid
  • Remove a small amount of acid before you add the solution
  • This is not a permanent fix, but it will extend the life of your battery

Where to Buy EDTA online UK


Created by Mistral Pure Chemicals. View website