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help choosing well pump setup

outboard1196

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Jan 15, 2024
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I'm looking to add a well pump for my off grid property , I currently have a solar setup 24v 200ah with 400w of panels with room to grow .
the well is 100' deep panels are 100' from well batteries are 50' from well. orignally i was looking at a 24v pump using this pump here but concerned about long run of cables and voltage drop . I started looking at brushless well pumps , I see some on ebay with controllers for around $300 but do I want to gamble with the quality ?
I have been looking at rpssolar for a while, the cost is high [er] but seems they stand behind the product ? I would be pumping to pressure tanks and mostly during the day but would also like to pump at night. when looking at brushless systems they prefer running direct off panels but battery is an option , but kind of vague as to how its done, hook battery direct to pv input ? I'd prefer to have brushless system hooked to my batter bank rather then panels , does this make sense? any input would be helpful , thanks.
 
grundfos are DC rated, most are 30-300v. so, unfortunately, with a 24v system, you're not going to be able to support DC direct on that. you'll need a DC-DC converter to step that up which, to get enough amperage to support a 3/4hp pump or larger, will cost more than an AC inverter. don't forget to account for the surge startup requirements for well pumps, which can be 100-150% of working load.

options are....
  • change to a 48v system
  • expensive dc-dc converter
  • go AC
  • roll the dice on a subpar quality pump
 
I met yesterday with my well driller about a new house we're building.Very experienced, well-regarded guy in our area. When I told him we were going solar, probably remaining off-grid, he said, "Grundfos SQ" without even a moment's hesitation. Told me that they were seeing a starting current of about 5 amps on the 240V pumps typical of our area (often 200-300 foot depth, I've noticed in talking with others) compared to about 17 amps from others they commonly install, for grid-tie only. That was enough for me! Grundfos SQ it is.

And no, we didn't discuss 120V, etc. 240V will be needed for several other things in the house, so makes sense to have a 240V well pump.
 
I met yesterday with my well driller about a new house we're building.Very experienced, well-regarded guy in our area. When I told him we were going solar, probably remaining off-grid, he said, "Grundfos SQ" without even a moment's hesitation. Told me that they were seeing a starting current of about 5 amps on the 240V pumps typical of our area (often 200-300 foot depth, I've noticed in talking with others) compared to about 17 amps from others they commonly install, for grid-tie only. That was enough for me! Grundfos SQ it is.

And no, we didn't discuss 120V, etc. 240V will be needed for several other things in the house, so makes sense to have a 240V well pump.
Yeah I've decided to go with an sq pump (115v) and inverter . gives me option to run from generator if I need it . same price as an rps pump .
 
I have a Franklin fhoton helical rotor setup and it's been flawless. Takes cd from panels to the controller box. I also bought the 120/240 box to allow ac power, and I've just been using that with an extension cord. I have the solar panels, just haven't mounted them yet. Soft start, water is about 100 deep, plus another 100' to storage tanks. Uses 1kW for 5gpm.
 
I have a Franklin fhoton helical rotor setup and it's been flawless. Takes cd from panels to the controller box. I also bought the 120/240 box to allow ac power, and I've just been using that with an extension cord. I have the solar panels, just haven't mounted them yet. Soft start, water is about 100 deep, plus another 100' to storage tanks. Uses 1kW for 5gpm.
Interesting , lots of information from franklin but I dont see anywhere to buy besides dealer. Requires a high DC input , would you share the cost of your system ?
 
I've got a Grundfos myself. Runs just fine and barely makes my 2x LV2424s grunt when the pump starts.
 
I keep looking at Grundfos but I'm not a pumpologist engineer and can't make sense of the sizing stuff. 😥 300ft deep, 4gpm min, 70psi min.
 
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