The S1-200 is a very efficient pump that operates using small amounts of power. We would suggest using a minimum of 200Wp of photovoltaic power with the pump system.
Depending on the application and location you may require more or less solar power to meet your water need.

When choosing a PV module to connect to the pump system the voltage (Vmp) should be
> 34 V for best performance, the open-circuit voltage (Voc) must not be above 55V DC.