NOVELTY - The cell plug incorporates hollow float chamber (30) in which hollow float container (37) filled with Styrofoam (40) is installed so as to move vertically. An elongated float needle (43) is attached to the float container so as to move vertically in hollow needle housing (52). A fill inlet cover (80) having a chamber (82) with a circular opening is connected to housing (52) for filling water into the battery. As the water level rises in the float chamber, the float container rises and the needle nose cone forms a fluid seal with the seat seal (66) and shuts off the water supply.    USE - Battery cell plug for replenishing water in batteries of e.g. golf carts.    ADVANTAGE - The battery cell plug does not require any outside power to circulate the refilling water, but relies solely on gravity feed of water into the cell. Diminishes risk of toxic and explosive gas hazards. The cells do not require a sight gage but only visual sighting of water overflowing when batteries are full. Installation of the system does not require any changes to be made, since all the parts are snap fitted into place.    DETAILED DESCRIPTION - A vent chamber disk (53) is molded in the needle housing and several vent guide ribs are formed in the surface of chamber disk. The rubber seat seal is inserted into the lower opening of needle housing for receiving the float needle. A vent chamber barrier (61) having an indented lower surface engages with the guide ribs, to form the vent chamber (62). A cell cap (71) having a hollow transition unit molded to the underside, is connected to the float chamber housing with a rubber gasket (79).    DESCRIPTION OF DRAWING(S) - The figure shows the cross sectional view of the basic cell plug.    Hollow float chamber (30)    Hollow float container (37)    Styrofoam(43) Elongate float needle (40)    Needle housing (52)    Vent chamber disk (53)    Vent chamber barrier (61)    Vent chamber (62)    Seat seal (66)    Cell cap (71)    Rubber gasket (79)    Fill inlet cover (80)    Chamber (82)