<div dir="auto">Do you have the 42-48 or the newer 55-48, l have used both in off grid AC Coupled systems with no issues, inverters freq shift and self power down. I did eliminate the battery temp sensor and use a resistor in its place to stabilize the charge rate.<div dir="auto">Can you again call out the issue you are having with the inverters as this might help answer or at least even resemble issue we might also be seeing.</div><div dir="auto">Fun times</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Mar 27, 2024, 7:14 PM William Miller via RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div lang="EN-US" link="blue" vlink="purple"><div class="m_-7337510375478816105WordSection1"><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"">Some of you may remember the problems I am having integrating a set of Fortress batteries with an off-grid Sunny Island/Sunny Boy ac-coupled system. If not, <a href="https://millersolar.com/MillerSolar/case_studies/36_SIFortress/36_SunnyIslandFortressIntegration.html" target="_blank" rel="noreferrer">here</a> is the case study.</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"">The problem has been in abeyance for the last few months because due to short days and cloudy weather. There has not been enough sunshine to cause a recurrence. Now that spring has sprung the problem is back.</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 did come up with a work-around: I installed a contactor to disconnect the Sunny Boys whenever the SOC gets to 90%. This works but it does waste some solar capability.</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 have been working with Fortress on the issue. They have been in touch and have been very generous in offering support and spending time trying to find a solution. Most important they have admitted the problem exists.</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"">To me this is very refreshing. This makes me want to use more Fortress products and sing their praises. I think my fellow wrenches would want to know about this great support when contemplating which battery products to use, which is the reason for this post.</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 an excerpt from an email received today from Fortress.</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:10.0pt;font-family:"Arial","sans-serif"">Hi William,</span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Apologies for the lapse in communication on this subject, we are still actively working on this case to provide you with a solution.</span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">We have confirmed here in our Lab that the older firmware does not resolve the issue as you have stated and the engineering and product teams are in discussions to provide a solution to this battery/inverter compatibility issue. We will provide updates on a solution as we receive them. I unfortunately do not have a timeline to provide, but we will have one soon.</span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Thank you for your patience.</span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Warm regards,</span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Galen Gennaria</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 will update the case study when new developments occur.</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</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/" target="_blank" rel="noreferrer">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></div>
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