<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Wrenches,<div class=""><br class=""></div><div class="">Thanks, all, for your responses. This recently retired ER Doc customer does have an inverter system (old SW\u2019s, one not so good on the scope). Grid and also two generators, Wanted a DC solution also. I like the Grundfos pumps so far, not their opinion to double the battery bank so it\u2019s 48 and use their charge controller. I see their expertise is AC only, or PV-direct DC. Yes, there\u2019s likely a DC-DC solution, somewhere out there, and it can be worked out given enough money and research. Seems Grundfos somewhat admits this. Good pump no matter, it seems. AC or PV-direct.<div class=""><div class=""><div class=""><br class="webkit-block-placeholder"></div><div class="">
<div style="color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Take care,</div><div style="color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""></div><div style="color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Gary</div><div style="color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""></div><div style="color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Gary Higbee<br class="">Windstream Solart<br class=""><a href="mailto:gary@windstreamsolar.com" class="">gary@windstreamsolar.com</a><br class="">541-954-3881<br class=""><br class=""></div>
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<div><br class=""><blockquote type="cite" class=""><div class="">On Aug 21, 2018, at 11:17 AM, Gary Higbee <<a href="mailto:gary@windstreamsolar.com" class="">gary@windstreamsolar.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html; charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Hi Wrenches,<div class=""><br class=""></div><div class="">I\u2019m assisting a customer and well person in replacing a failed Lorentz ETApump (after 15 years of intermittent use). We\u2019re looking for a quality DC-DC converter to power a not-yet- ordered Grundfos SQFlex 6 SQF-3 from a 24 V Surrette battery bank (wish it was 48!). The pump draws a max of 8.4A and the curves say we\u2019ll need about 600 watts so I figure we\u2019d want at least 70 volts out. Ideal would be a higher DC output, say 200V (save a couple hundred feet of larger copper, greater efficiency) and at least 3A (see questions).</div><div class=""><br class=""></div><div class="">The primary power source will be 240V AC but my customer wants a fallback for battery operation. We plan to use the Grundfos IO 101 SQFlex switch box, which will switch to DC if the AC fails. Also the CU 200 SQFlex control unit, so we can accommodate the existing float switch up the hill, etc.</div><div class=""><div class=""><br class="webkit-block-placeholder"></div><div class=""><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">The Grundfos tech person I spoke with today said the DC system should be able to supply 8.4A, regardless of the DC voltage.The pump curve says we need 600W for maximum performance at the lift we\u2019ve got. It seems to me that if we\u2019ve got 200V and need 600W we\u2019d be drawing 3A. Yet if the Grundfos factory line is there should be 8.4A available that\u2019s 1680W. The tech guy said he didn\u2019t have specific information why we\u2019d need 8.4A regardless of pump input voltage. </div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><br class=""></div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">The Grundfos Product Guide says:</div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><br class=""></div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><b class="">Max. ratings are as follows:</b></div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div class="" style="margin: 0px; font-stretch: normal; line-height: normal;"><b class="">\u2022 Maximum power input (P<span class="" style="font-stretch: normal; line-height: normal;">1</span>) of 1400 W</b></div><div class="" style="margin: 0px; font-stretch: normal; line-height: normal;"><b class="">\u2022 maximum current of 8.4 A</b></div><div class="" style="margin: 0px; font-stretch: normal; line-height: normal;"><b class="">\u2022 maximum speed of 3600 rpm </b>(think I read somewhere it\u2019s 3000 rpm for this helical rotor model)</div><div class="" style="margin: 0px; font-stretch: normal; line-height: normal;"><b class=""><br class=""></b></div><div class="" style="margin: 0px; font-stretch: normal; line-height: normal;"><b class="">The pump delivers its maximum performance when </b><b class="">one of the above parameters is reached.</b></div></div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><br class=""></div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">Two questions:</div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><br class=""></div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">1) Do any of you have experience running the SQFlex on DC, and what to make of the 8.4A at any input voltage factory recommendation? Maybe basic amps/volts/power calculations aren\u2019t applicable given the pump electronics?</div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><br class=""></div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">2) Are you aware of any DC-DC converters that will get us from a nominal 24V battery bank to 200V, or somewhere between 70 and 200V, with an appropriate current limiting amp rating to get us at least 600W (depending on thoughts regarding the above question)?</div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><br class=""></div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><br class=""></div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">Thank you,</div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><br class=""></div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">Gary</div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><br class=""></div><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">Gary Higbee<br class="">Windstream Solar<br class="">Oregon License 17LRT<br class="">Renewable Energy Consulting<br class=""><a href="mailto:gary@windstreamsolar.com" class="">gary@windstreamsolar.com</a><br class="">541-954-3881</div></div></div></div></div></blockquote></div><br class=""></div></div></div></body></html>