A system for charging a battery within an at least partially electric vehicle. A sensor unit detects triggering of a flush water stream through the toilet bowl within the flushing water period t1-t2 at a time ts. The tread and value of the points may be quantized, and certain of the quantizations may be discarded before the quantizations are transmitted. When the first end and the second end of the sound absorbing member are attached to the periphery of the opening, at least one side opening is at least partially defined by the intermediate portion and the perimeter of the opening, and a sound transmission flow path through open space between the opening and the side opening comprises at least one change of direction greater than 45 degrees. In order to provide alignment across the entire face of the components, it is preferred to have at least one component with a plurality of projections and at least one component having a plurality of cavities.