Letter Re: Solar Well Pump


I agree with GL, the Grundfos SQF line of off-grid well pumps are superior products. My well is using the 11-SQF-2 pump. The correct operating voltage range is 30-300 VDC or 90-240 VAC @ 50/60 Hz. Maximum current draw of this set of pump products is 8.4 amps, regardless of input voltage. The pump contains an MPPT power controller. Oh, these are NOT inexpensive pumps.

Note, if you are supplying less than 120 volts, the GPM of the pump must be down-rated. This is important when running from solar panels but even more so when running from batteries. See the technical literature for details. It is a very good, thorough document and details configurations for solar, wind, and generator environments. Take note that if your generator outlets are GFCI, Grundfos says that the pump will not operate. I have not confirmed this, as my generator is not GFCI.

Grundfos literature for the SQFlex pumps can be found at Grundfos SQFlex Literature – R.G.