This International Standard defines predicted short-term characteristics (instantaneous and for a typical daily period) of direct coupled photovoltaic (PV) water pumping systems. It also defines minimum actual performance values to be obtained on-site. It does not address PV pumping systems with batteries. The parameters defining the photovoltaic power generating system (PVPGS) and the standard days@ used to provide data in figure 1@ should be in accordance with IEC standards@ in preparation@ on the reference solar day.