1. MPPT function, even it is cloudy, pump still can maintain low speed running. 2. AC input compensation function. such as solar power 80%, inverter will use 20% from AC input to supply 100% to water pump, solar power is 100%, inverter will not use AC input, save AC cost 3. no water sensor function, water tank full sensor function4. widely PV working voltage 150VDC to 800VDC.