Abstract: The indicator cap (22 or 80) is formed of a base connected to a transparent tube (46) forming a cylindrical cavity (48) receiving a colored or opaque float (70). The position of the float (70) within the tube (46) indicates the level of the electrolyte in the cell (20) of the battery (10). The float contains an upper collar (74) which cooperates with top vent (60) or side vent (92) to seal the cell. The collar (74) engages the annular disc (76) or apertured collar (86) to prevent the float (70) from falling into the cell (20) when the cap (22 or 80) is removed from the aperture (24).