MPPT: always the maximum power available.
Based on the varying conditions of solar irradiation and temperature, MPPT (Maximum Power Point Tracking) maximises the electrical power drawn from the panels and therefore the amount of water pumped.
The greater the solar irradiation the faster the pump’s rotation speed, and consequently water flow increases.
When solar irradiation decreases (due to clouds or the different times of day), the pump reduces frequency and therefore the flow, but it continues to provide water until the irradation falls below a minimum level necessary to ensure operation.