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Wrenches, A good client of ours is a rancher in the New Mexico/Arizona border area. He has a specific need for which I couldn't offer a simple system. He needs to raise water from a lake 400+/- vertical feet to a 100K gallon storage tank for agricultural use. The site is remote. The amount is substantial - about 10-12 gpm continuously, 24/7. He would like to use 4 Grundfos SQ Flex pumps at about 2.5-3 gpm, each running array-direct feeding a common pipe to the tank. He then wants to use about an 8kW (derated to 6kW for 7,500' elevation) diesel generator (with standard two-wire automatic start) to run all four pumps when the sun goes down, and shut off and transfer back to PV when the sun comes up the next morning. How might this be done? If we assume that each pump has four 210W modules, that would be an 80Vnom array with MPP around 120V and Voc around 150V. I would assume that both of these voltages are too high to use any stand-alone AGS, such as Atkinson or Magnum. We considered a separate tiny 12V or 24V battery with small PV module, used just to power an AGS voltage sense signal, with the voltage difference between float (13.6V) and rest (12.7V) triggering a voltage-actuated start signal, but rejected this as problematic as battery temperatures affected charge voltages. A self-contained time switch, such as some of the newer Intermatic units, might work, if the right model can be identified and isn't a substantial phantom load. We would also have to adapt a relay to switch between sources, with a 120 or 240 V AC relay coil current, energized by the generator. The Grundfos IO101 AC interface unit is manual only. Has anyone solved this problem? Any ideas for a reasonably simple and trouble-free approach would be welcome. Thank you, Allan --
Allan Sindelar al...@positiveenergysolar.com NABCEP Certified Photovoltaic Installer NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Positive Energy, Inc. 3201 Calle Marie Santa Fe, New Mexico 87507 505 424-1112 www.positiveenergysolar.com
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