How many solar panels question for Grundfos 11 SQF-2?

john.sundog

This kind of question has probably been answered previously but I couldn't find it in an hour of searching - my apologies if so.

I'm helping my friend/neighbor with his pump installation, a Grundfos 11 SQF-2 with CU-200 controller and IO-101 switch box (my experience is with Lorentz). The SWL in his well is 25 feet but he thinks the top 100-125 feet of water may recover slowly and thus experience drawdown, so the actual water level could be anywhere from 25 to 150 feet depending on how long the pump has been running on any given day. The pump is set at 200 feet.

He has seven REC-245 panels which I gather are 245 watts at a nominal 30 VDC. Here's the problem. The supplier told him he should be very careful not to use too many panels and recommended two, based on the 25' SWL. However, the Grundfos literature recommends at least 120 VDC (4 panels in series) and allows up to 300 VDC. Is there any reason not to simply run the seven panels in series? Would this be too much power/current when he's only lifting 25 feet, as the supplier states?

Thanks very much!

Cariboocoot

Re: How many solar panels question for Grundfos 11 SQF-2?

Welcome to the forum.

In this case seven 245 Watt panels (1715 Watts) would exceed the recommended maximum for the 11 SQF-2 (1400 Watts). I think you should limit it to five of those panels.

john.sundog

Re: How many solar panels question for Grundfos 11 SQF-2?

Cariboocoot wrote: »

Welcome to the forum.

In this case seven 245 Watt panels (1715 Watts) would exceed the recommended maximum for the 11 SQF-2 (1400 Watts). I think you should limit it to five of those panels.

Thanks, Cariboocoot. I missed that spec. Oops!

Texas Wellman

Re: How many solar panels question for Grundfos 11 SQF-2?

You don't need to worry about over pumping the well. The ones I have used had built in dry run protection. Set the panels up for max ~120v configuration.