Storage battery with single fill valve

A multicell lead acid storage battery is fitted with a one piece cover. A rotatable disc valve is mounted on the cover, the valve being of such a size that it covers a portion of all cells. A filling well and a vent opening for each cell are located under the disc valve. In a first angular position of the valve, the filling wells are exposed and the vent openings are sealed, and in a second position, the wells are closed and the vents are opened. When the wells are exposed, the passages into the cells are clear, expose the top of the cell elements and permit the insertion of a hydrometer into the cell. In order that the top of each element is exposed, the location of the center cell filling wells and vent openings are nearer the axis of the valve than the openings in the two end cells. Rotation of the valve may expose a legend relating to the valve position.