When this occurs, you have to totally desulfate the battery to ensure that it again holds a fee. Desulfation is also called battery "reconditioning." Since batteries contain poisonous chemicals, such as lead acid, you should take safety preventative measures. Always put on goggles and handwear covers when doing this treatment. https://reconditioning-battery-ch71235.blogdon.net/h1-evaluation-ez-battery-reconditioning-does-it-function-or-otherwise-h1-51188662