Abstract: An electrolyte solution which increases the service life and charge acceptance of lead-acid batteries. The electrolyte solution includes an aqueous solution of sulfuric acid and boric acid. The boric acid has a concentration from about 2.5 grams per liter to less than 5.0 grams per liter of the aqueous solution of sulfuric acid. This electrolyte solution is used as a method of improving the service life and charge acceptance of lead-acid batteries.