Valves The Battery Filling System valves are manufactured with the highest quality materials that keep all working parts above the battery cell. BFS manufactures valves to suit all industrial cell vent openings. The patented, reliable lever arm inside the valve allows the battery to be filled with water at static pressures ranging from 6 psi to 20 psi. Only BFS offers such unique performance and a variety of specialty valves to meet the needs of the battery industry. Years of research and development have shaped the technology of this system. Each and every valve is independently tested to ensure the components are working properly. The production of over 10,000,000 valves per year have made the company the global market leader in this field. *The valves must be filled using an approved water delivery item.