Abstract: A wet-type self energizing power pack is disclosed which uses an electrolyte essentially made of oil, sulfuric acid and a minor amount of acetic acid. The device includes positive and negative plates which are separated by means of separators. The positive plates mainly consist of an alveolated structure filled with a compound of carbon, lead oxide, glycerine are provided with a diagonal row of holes while the negative plates are made of lead-tin alloy and are provided with two rows of holes, one appearing at the top and the other one appearing at the bottom of the plate. A method of preparing the electrolyte is disclosed as well as the method of charging the battery.