Abstract: An improved wet plate battery for use in the electrical system of an internal combustion engine and adapted to produce hydrogen and oxygen gases for enrichment of the air/fuel mixture is disclosed. The battery includes a plurality of electrical generating cells having positive and negative plates immersed in an electrolyte. Air tubes extend through the battery case and provide communication between the space below the plates with the atmosphere. A gas discharge port is provided in the top of the case above the electrical generating cells and is connected through suitable tubing to a source of vacuum in the induction system of the engine.