You could connect a solar panel directly to a water pump. It is not a good idea, though. The erratic pulse of electricity produced by the solar panel will burn out the pump at some point. That process can take.
[pdf] Solar photovoltaic water pumping system, also known as photovoltaic water pump or solar water pump system, converts solar energy into electricity through solar cell modules and then drives the pump to r.
[pdf] Three solar inverters can drive a water pump and convert photovoltaic direct current into alternating current. It is an inverter designed for running water pumps using solar power. It directly transforms the direct power produced by solar panels into an alternating current to drive the pump.
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