<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div dir="ltr"></div><div dir="ltr">I’m going to both agree and disagree </div><div dir="ltr"><br></div><div dir="ltr">Agree The older inverters ( Schneider, Outback, etc) your drawing is correct. </div><div dir="ltr"><br></div><div dir="ltr">Disagree For many new inverters ( sol ark, ev4, fortress) they bring ac coupling into the inverter directly. </div><div dir="ltr">Usually on the generator input and not in the backup loads panel. </div><div dir="ltr"><br></div><div dir="ltr">And I will also disagree about the statement that these inverters are not designed for ac coupling. </div><div dir="ltr">Agreed that the earlier non rule 21 compliant versions didn’t have any internal control and required external relay control to prevent overcharge. </div><div dir="ltr"><br></div><div dir="ltr">Newer versions of Schneider, OB, have  frequently shift which works with newer gt inverters to address the ac coupling overcharge concerns. While creating potential new issues for loads with up to 64 hz. </div><div dir="ltr"><br></div><div dir="ltr"><br></div><div dir="ltr">Jay</div><div dir="ltr"><br></div><div dir="ltr"><br></div><div dir="ltr"><br></div><div dir="ltr"><br></div><div dir="ltr"><br><blockquote type="cite">On Oct 28, 2023, at 2:15 PM, William Miller via RE-wrenches <re-wrenches@lists.re-wrenches.org> wrote:<br><br></blockquote></div><blockquote type="cite"><div dir="ltr"><meta http-equiv="Content-Type" content="text/html; charset=us-ascii"><meta name="Generator" content="Microsoft Word 14 (filtered medium)"><style>@font-face { font-family: Calibri; }
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div.WordSection1 { page: WordSection1; }</style><div class="WordSection1"><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">Friends:</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">I am starting to get the impression that there is a diversion on the understanding of the definition of AC coupling within the industry.  I think this definition needs to be clarified.</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">Below is a diagram of what I understand is a DC coupled system (I hope these diagrams come through):</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""><div><image003.png></div></span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">A battery inverter that receives AC power into an AC input port is <u>not</u> AC coupled.</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">Here is an AC-coupled system:</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""><div><image005.png></div></span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">What makes AC-Coupled systems unique are the problems presented by sending power <u>backwards</u> through a battery inverter.  This is not how battery inverters were originally designed to operate.  These systems require careful consideration to avoid battery overcharging.</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">Do we have consensus on this definition?</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">William Miller</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial","sans-serif"">Miller Solar</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial","sans-serif"">17395 Oak Road, Atascadero, CA 93422</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial","sans-serif"">805-438-5600</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial","sans-serif""><a href="http://www.millersolar.com/">www.millersolar.com</a></span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial","sans-serif"">CA Lic. 773985</span></p><p class="MsoNormal"> </p><p class="MsoNormal"> </p></div>
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