Pumping system inverter

[Ian]

Hello everyone!

I'm stuck with a problem in pumping systems.

The suggested pump and PV powers are 2.2 kW and 2.8kW each. I am using solar panels of 370 W and 34 V, so I have to put a string of 7 panels. The program recommends me to put 2 strings, so I'll have 4.7 kW max. Ok then I choose an inverter of 3 kW but I can't cover the water needs, so I decide then to add another string, having 7kW (max), but then less water is pumped. WHY???? If I use only one string, more water is pumped than if I use 2 or 3. Why is this happening????

Also if I use an inverter of 2.2 kW, the water needs are covered with 2 strings of 7 panels, but I don't understand why using a 3 kW inverter (only changing the inverter, not the panels) with the same operating conditions (mppt conditions and maximum voltage conditions) makes the system pump the half of the water. The threshold difference is only 8 Watts.

Thank you!!

[Lazare Fesnien]

Hi,

This happens if you pump more than the drill can.

The deep well is defined by a dynamic level and a drawdown, if your PV field and your pump are oversized, you will pump faster than the regeneration of the deep well