I have a cabin in the mountains watered by a system similar to yours. It has a 1.5hp AC Grunfos pump that I power by solar. My running watts is about 2400W, and I have 4500 watts of panels to support that. Like you, I pump into a 5000 gallon storage tank positioned up the hill. However, I chose to go the AC route, and I'm very satified with the performance of my system. Basicly, I pump water only on bright clear days into the tank, then have on-demand running water because there's a one-way valve to keeps water from draining back into the well. I pump water 6-8 hours per day every two weeks or so in the summer when irrigation water is in high demand.
Rather than pulling the pump (which I can tell you is not something to look forward to) I'd recommend simply adding enough panels to support your pumping rate, which I'd say should be around 2400 watts or so. What kind of inverter do you have, and what's your system voltage.
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1. The grundfos pump is a good pump very few will argue with that. I would consider going to the sqf-6 or 11 to get you the most gallons a day.
2.those panels would work fine. The pump can use up to I belive 1200 watts (not the 340 you have listed. That might be a number for how many watts it takes to get 3 gpm from 160') but anyway even if you go over the max watts it will not hurt it and is okay.
3. Yes you can use that box with a separate switch to turn it off when the tank is full.
4.the cu101 box you can use to put power to it (in your case use a switch that when the tank is almost empty would turn it on for a few inches then shut it off and go back to solar) , or use some kind of a transfer box if you don't need it to be automatic. (you can plug the pump directly in with a 120 volt plug in but it isn't rated for dc to connect the panels with)Leave a comment:
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DC pumping from deep well to cistern...
Ok, this is my first post, except for my introduction. I live in the mountains of Puerto Rico and have a newly installed PV system that I don't think is working properly but that is the subject of another post. I have a 160' deep well with a 220v 3/4hp Grundfos pump that takes from 1000-1200w when it is on, which really drains my batteries (this is the pump that I have always used with grid energy). What I would like to do is replace it with a DC powered pump with dedicated solar panels and use the low flow when the sun is shining to fill a 3000 gallon cistern, which can then provide gravity fed water to the house. The following is what I think will work for me, but would appreciate any comments or advice!!!
1. Submersible Grundfos SQflex 3-SQF-2 (30-300VDC, 100-340w, 360' head, 3gpm) - The well is 160' deep, so this gives me plenty of vertical distance to move water to the cistern. I like that the pump will work with different voltages, just pumping less with a smaller voltage. Although it is pricier than some other pumps, the 15-20 year without service is a big advantage, as it is a hassle and costs me $225 every time I have to pull the pump. I also like that in an emergency I can use AC from the power company, the inverter or a gasoline generator.
file:///C:/Users/User/Desktop/SQF_Brochure_L-SQ-SL-010.pdf
https://thesolarstore.com/grundfos-s...ump-p-522.html (I'm not sure if I can post a commercial website, but it is just for the equipment details)
2. Three panels REC 240w, 8a, 29.9v in series for a total of 717.6w, 8a, 89.7v (is the excess in watts a problem?). These panels are available locally.
3. CU200 Interface box with water level switch, to turn off the pump when the cistern is full.
There is another possible component, but I'm not sure if this is necessary to switch over to AC, or if I can just use some simple manual control, like a transfer switch?
4. IO101 Interface box - Supposedly changes automatically to AC when it is available, but I would want to switch manually, because I want to preferentially use DC.
Thanks for any help you can give me and Happy New Year!!!
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