Grundfos SQF pump help, please. Thank you.

[chetwynd]

Cross-posting this so I don't have to potentially wait a month for input.

I have a Grundfos 11 SQF 2 pump, hooked up to the Grundfos CU-200 control box.

My input is 4 solar panels with the following specs:

Pmax: 250W
Isc: 8.9 A
VOC: 37.4V

I have them wired in series, feeling into the control box.

Right now in mid-day sun the control box is showing ~550W. 127V give or take.

What I'm trying to figure out is whether I'm better off, given the specs of the pump, having them wired in series like they are, or series/parallel, or what.

My pump is something like 225 feet below the surface, and the water level is around 80' below the surface.

Can anyone please help? I'm trying to maximize the amount of water that gets pumped.


This is the pump: https://product-selection.grundfos.c...specifications

[azdave]

My knowledge of the subject is limited (solar well pumps) but I will always opt for the higher voltage of series-connected solar panels where you need max efficiency. As long as your series-connected panels will not exceed 300VDC on the coldest, full-sun day of the year, you should be good. The pump and controller seem to be optimized for taking advantage of these higher voltages. The documentation for the pump clearly states that the efficiency is "significantly higher" at voltages over 100VDC input so I would definitely not wire your panels in parallel.