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--></style></head><body lang="EN-US" link="blue" vlink="purple"><div class="WordSection1"><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#1f497d">Glenn:</span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#1f497d">I am aware that SMA does not support closed loop. This is does not negate the point I am making. </span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#1f497d">There is a problem in that Fortress claims the E-vault is compatible with Sunny Island. We should not have relied on Fortress for compatibility claims. The client really wanted lithium and already had a big SI system. I want to find alternatives to lead-acid with its very limited lifespan. A lot of resources are wasted replacing and processing sulfated lead acid batteries. </span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#1f497d">We reviewed the Fortress compatibility documents and made a decision based on incomplete information. This is my fault for not researching further. However we find ourselves with SI and E-vaults. I am trying to make the system work and share what I am learning because I think there are valuable lessons here.</span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#1f497d">I started with open loop and I had greater problems with SOC inaccuracy so I chose closed loop as an attempted work-around to the problem. The system performs generally more accurately with closed loop but does have the problems I described. I am still learning and trying to get this system to behave.</span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#1f497d">I am not sure how that “taints” my position. If my findings are inaccurate I’d love to have you or anyone point out the errors so my understanding improves and I can better serve my clients. I do believe it is valid to assume any system that offers SOC can become out of calibration.</span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#1f497d">I strive to give back to the industry by sharing fully what I have learned. I don’t claim to be right all the time and I am certainly open to other conclusions. Am I incorrect with the information I presented or the conclusions I have drawn?</span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#1f497d">William</span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#1f497d"> </span></p><div><p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#1f497d">Miller Solar</span></p><p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#1f497d">17395 Oak Road, Atascadero, CA 93422</span></p><p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#1f497d">805-438-5600</span></p><p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#1f497d"><a href="http://www.millersolar.com/">www.millersolar.com</a></span></p><p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#1f497d">CA Lic. 773985</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p></div><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#1f497d"> </span></p><div><div style="border:none;border-top:solid #b5c4df 1.0pt;padding:3.0pt 0in 0in 0in"><p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Glenn Burt [mailto:<a href="mailto:Glenn.burt@glbcc.com">Glenn.burt@glbcc.com</a>] <br><b>Sent:</b> Friday, February 9, 2024 11:38 AM<br><b>To:</b> William Miller via RE-wrenches; <a href="mailto:offgridsolar@sti.net">offgridsolar@sti.net</a><br><b>Cc:</b> William Miller<br><b>Subject:</b> Re: [RE-wrenches] State of Charge Meter for Sol-Ark</span></p></div></div><p class="MsoNormal"> </p><div><div><p class="MsoNormal"><span style="font-size:10.0pt">William,</span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt"> </span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt">You are aware that SMA does not support closed loop battery connections with any manufacturer? </span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt">I have had many conversations with trailers and engineers there and have chisen not to support switching to lithium with SI for tbis reason.</span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt">I think this taints your position in this matter.</span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt"> </span></p></div><div><div><p class="MsoNormal"><span style="font-size:10.0pt">-Glenn</span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt">Sent from my 'smart'phone, so please excuse typos and spelling errors.</span></p></div></div></div><div><div id="LGEmailHeader"><div><p class="MsoNormal"><span style="font-size:10.0pt"> </span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt">------ Original message------</span></p></div><div><p class="MsoNormal"><b><span style="font-size:10.0pt">From: </span></b><span style="font-size:10.0pt">William Miller via RE-wrenches</span></p></div><div><p class="MsoNormal"><b><span style="font-size:10.0pt">Date: </span></b><span style="font-size:10.0pt">Fri, Feb 9, 2024 2:33 PM</span></p></div><div><p class="MsoNormal"><b><span style="font-size:10.0pt">To: </span></b><span style="font-size:10.0pt"><a href="mailto:offgridsolar@sti.net">offgridsolar@sti.net</a>;RE-wrenches;</span></p></div><div><p class="MsoNormal"><b><span style="font-size:10.0pt">Cc: </span></b><span style="font-size:10.0pt">William Miller;</span></p></div><div><p class="MsoNormal"><b><span style="font-size:10.0pt">Subject:</span></b><span style="font-size:10.0pt">Re: [RE-wrenches] State of Charge Meter for Sol-Ark</span></p></div><div><p class="MsoNormal"><span style="font-size:10.0pt"> </span></p></div></div><div><div><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366">Dave:</span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366">I have to disagree with you here. To my knowledge every SOC system relies on coulomb counting and applying an efficiency value. That efficiency value is dependent on changing variables such as temperature, age of the batteries, charge rate, discharge rate-- to name a few. Every SOC system I have studied requires periodic recalibration. Maybe Discover is different but here is my experience with Fortress. </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366">Below is a chart of SOC versus Battery Voltage for a 4 Sunny Island system in a closed loop installation with 5 Fortress E-vaults:</span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366"><img border="0" width="773" height="1004" id="Picture_x0020_1" src="cid:image001.jpg@01DA5B4F.8346CC10" alt="cid:image001.jpg@01DA5B4F.8346CC10"></span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366">Inside the ellipse note that at 6:00AM the SOC is 55% and the battery voltage is about 50.8. At 4:00PM pm the same day SOC is again at 55% but the battery voltage is about 50.0 VDC. This is a drift in calibration of 0.8 VDC in 10 hours. In the context of LiFePo4 systems 0.8 VDC is a lot. Because this is closed loop, the drift was created in the BMS units, not the Sunny Island.</span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366">Drake, to your question: The consequences depend on how much the system relies on SOC for operational mode decisions. I work almost exclusively with Outback and SMA SI and primarily in the off-grid segment. Since the SI is SOC-centric, the consequences experienced during the period charted above was that the system failed to start the generator and the system shut down.</span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366">I am new to the use of Lithium batteries and don’t work a lot with SI so it took me two trips to figure out what was happening. The diagnosis was complicated by a failed SD card and a catastrophic generator failure (shorted windings). It took a few days to get a replacement generator and the interim the Fortress BMSs failed to recalibrate and this caused the incorrect correlation between VDC and SOC.</span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366">In conversation with Fortress tech support I was advised to make sure the battery voltage gets to 54.4 at least once per week. This is the voltage at which the E-vaults recalibrate SOC. During the winter this is sometimes difficult to do. I can’t rely on the SI generator to auto-start and achieve 54.4 because it triggers on SOC values and if those values are wrong then the generator may shutoff prematurely, failing to reach 54.4. In this case the generator failed to start at all as a direct result of inaccurate SOC and the system crashed, causing an inconvenience to the client and to me. </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366">There are some settings on the SI that may force a full charge but I haven’t drilled down yet to see if this can be configured to ensure that 54.4 once per week. If anyone has experience with this and can chime in it may save me some time. I suspect all settings rely on SOC so there will be no built in solution.</span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366">If the inverter here was an Outback and I was not relying on an FNDC to control generator start (which I never do), this problem would not happen. The Outback would react to battery voltage only, as monitored over three different time periods. This is a superior method for sure.</span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366">Battery inverters are very smart these days, but sometimes not quite smart enough…</span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366">Drake, thanks for asking.</span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366">William</span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366">PS: Brainstorming a solutions here: </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366">A: I am sure I could program an Arduino or Raspberry Pi to take over generator auto-start duties. I don’t prefer homemade solutions because of the time required to develop and test and I am not good at building interfaces.</span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366">B: Maybe I could install a Mate3s and one FM60 charge controller. The charge controller would not connect to PV because this is an AC coupled system, but if were connected to the batteries it could monitor battery voltage and the internal aux relay could control the generator.</span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366">Ideas, anyone?</span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366">WM</span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p><div><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Arial","sans-serif";color:#993366">Miller Solar</span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Arial","sans-serif";color:#993366">17395 Oak Road, Atascadero, CA 93422</span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Arial","sans-serif";color:#993366"><a href="tel:805-438-5600">805-438-5600</a></span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Arial","sans-serif";color:blue"><a href="http://www.millersolar.com">www.millersolar.com</a></span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Arial","sans-serif";color:#993366">CA Lic. 773985</span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#993366"> </span></p></div><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p><div><div style="border:none;border-top:solid #b5c4df 1.0pt;padding:3.0pt 0in 0in 0in"><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> RE-wrenches [mailto:<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of </b>Dave Angelini Offgrid Solar via RE-wrenches<br><b>Sent:</b> Friday, February 9, 2024 9:29 AM<br><b>To:</b> RE-wrenches<br><b>Cc:</b> Dave Angelini Offgrid Solar<br><b>Subject:</b> Re: [RE-wrenches] State of Charge Meter for Sol-Ark</span></p></div></div><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> </p><div id="v1_rc_sig"><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif"">Hi Drake,</span></p></div><div><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif""> </span></p></div><div><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif"">I do not think there is a lack of accuracy in a good closed loop LFP battery system. The steep curve of Lithium is just not accurate for voltage and the Soc measurement from a quality BMS is super accurate.</span></p></div><div><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif""> </span></p></div><div><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif"">All I use is the Discover AES and unlike others here, I do not have any issues over 4 years and 45 mostly Offgrid homes.</span></p></div><div><pre><span style="font-size:12.0pt">The closed loop UL 9540 systems save alot of fuel in generator use, are simple, and have happy clients for me.</span></pre><pre><strong><span style="font-size:12.0pt;font-family:"Courier New"">Dave Angelini Offgrid Solar</span></strong></pre><pre><strong><span style="font-size:12.0pt;font-family:"Courier New"">"we go where powerlines don't"</span></strong></pre><pre><strong><span style="font-size:12.0pt;font-family:"Courier New""><a href="http://members.sti.net/offgridsolar/" target="_blank"> </a></span></strong><strong><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";background:white;font-weight:normal"><a href="https://offgridsolar1.com/">https://offgridsolar1.com/</a></span></strong><strong><span style="font-size:12.0pt;font-family:"Courier New""><a href="http://members.sti.net/offgridsolar/" target="_blank"> </a></span></strong></pre><pre><strong><span style="font-size:12.0pt;font-family:"Courier New"">e-mail <a href="mailto:offgridsolar@sti.net">offgridsolar@sti.net</a></span></strong></pre><pre><strong><span style="font-size:12.0pt;font-family:"Courier New"">text <a href="tel:209%20813%200060">209 813 0060</a></span></strong></pre></div><p><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""> </span><span style="font-size:10.0pt"></span></p><p id="v1reply-intro"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">On <a href="tel:2024-02-09%208">2024-02-09 8</a>:05 am, Drake Chamberlin via RE-wrenches wrote:</span><span style="font-size:10.0pt"></span></p><blockquote style="border:none;border-left:solid #1010ff 1.5pt;padding:0in 0in 0in 5.0pt;margin-left:0in;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt"><div id="v1replybody1"><div><p><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">How does the lack of accuracy in SOC detection affect the usefulness of closed loop systems?</span><span style="font-size:10.0pt"></span></p><div><p><em><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">Drake Chamberlin</span></em><span style="font-size:10.0pt"></span></p><p><em><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">Athens Electric LLC</span></em><span style="font-size:10.0pt"></span></p><p><em><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">Ohio Electrical Contractor’s License 44810</span></em><span style="font-size:10.0pt"></span></p><p><em><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">NABCEP Certified PV Installation Professional</span></em><span style="font-size:10.0pt"></span></p></div><p><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""> </span><span style="font-size:10.0pt"></span></p><p id="v1v1reply-intro"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">On <a href="tel:2024-02-05%2011">2024-02-05 11</a>:36, William Miller via RE-wrenches wrote:</span><span style="font-size:10.0pt"></span></p><blockquote style="border:none;border-left:solid #1010ff 1.5pt;padding:0in 0in 0in 5.0pt;margin-left:0in;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt"><div id="v1v1replybody1"><div><div><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1f497d">Jason:</span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1f497d"> </span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1f497d">I am careful about getting my clients too dependent on SOC readings. SOC is a calculated value based on changing variables and is notoriously inaccurate.</span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1f497d"> </span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1f497d">Below is a screenshot of the Optics reporting for a client. The graph line that begins as the lower of the two is the SOC, the other is voltage. The SOC is out of calibration until about noon when it jumps from about 20% to about 80%. This does not mean the SOC changed by that amount, it means that it was just very wrong. Who knows when it is correct?</span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1f497d"> </span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1f497d">In spite of repeated entreaties this client still reads the SOC and becomes concerned when it gets low-- even if the voltage level indicates the batteries are well charged. I have to deal with his misplaced anxiety.</span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1f497d"> </span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1f497d"> </span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><b><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">Error! Filename not specified.Error! Filename not specified.<span style="color:#1f497d">Error! Filename not specified.</span></span></b><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1f497d"> </span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1f497d">This problem appears to occur across all battery/inverter technology. For example, SMA touts their "coulomb counting" as more accurate than others but I have witnessed otherwise. You'd think that BMS units built by lithium manufacturers for their own products would be consistently accurate but even those BMS units need to recalibrate frequently, this according to the battery manufacturer's engineers.</span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1f497d"> </span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1f497d">It would be nice to offer clients a simple, accurate method of ascertaining battery charge levels. SOC is not that method. I train my clients to watch voltage levels and to understand these values are elastic. If you can see trends in the battery voltage, so much the better. This is why I like the Outback Optics interface. This is also why a good AGS system examines battery voltage over time.</span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1f497d"> </span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1f497d">I no longer install Outback FNDC units. Without them there is no SOC reading. I don't install Sunny Island systems—they are SOC centered and suffer for it.</span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1f497d"> </span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1f497d">William</span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1f497d"> </span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1f497d">Miller Solar</span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1f497d">17395 Oak Road, Atascadero, CA 93422</span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1f497d"><a href="tel:805-438-5600">805-438-5600</a></span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1f497d"><a href="http://www.millersolar.com/" target="_blank">www.millersolar.com</a></span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1f497d">CA Lic. 773985</span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1f497d"> </span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><strong><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></strong><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> RE-wrenches [mailto:<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a>] <strong><span style="font-family:"Tahoma","sans-serif"">On Behalf Of </span></strong>Jason Szumlanski via RE-wrenches<br><strong><span style="font-family:"Tahoma","sans-serif"">Sent:</span></strong> Sunday, February 4, 2024 7:30 AM<br><strong><span style="font-family:"Tahoma","sans-serif"">To:</span></strong> RE-wrenches<br><strong><span style="font-family:"Tahoma","sans-serif"">Cc:</span></strong> Jason Szumlanski<br><strong><span style="font-family:"Tahoma","sans-serif"">Subject:</span></strong> [RE-wrenches] State of Charge Meter for Sol-Ark</span><span style="font-size:10.0pt"></span></p><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""> </span><span style="font-size:10.0pt"></span></p><div><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">Are there any off the shelf solutions to view battery SOC via a wired meter mounted remotely on a property? I have a client with a simple voltage based meter for lead acid batteries that they are accustomed to using as a quick and approximate gauge of SOC. They want something similar for their new Sol-Ark with EG4 LL batteries. </span><span style="font-size:10.0pt"></span></p><div><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""> </span><span style="font-size:10.0pt"></span></p></div><div><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">They will have smartphone app visibility, but they want something they can see inside the house without picking up a phone or going out to the inverter. Ideally the SOC will come from the inverter or the battery itself, not an external source (to avoid discrepancies).</span><span style="font-size:10.0pt"></span></p><div><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""> </span><span style="font-size:10.0pt"></span></p></div><div><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">Jason Szumlanski</span><span style="font-size:10.0pt"></span></p></div><div><p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">Florida Solar Design Group </span><span style="font-size:10.0pt"></span></p></div></div></div></div></div></div><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""> </span></p><div><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:10.0pt;font-family:"Courier New"">_______________________________________________<br>List sponsored by Redwood Alliance<br><br>Pay optional member dues here: <a href="http://re-wrenches.org" target="_blank">http://re-wrenches.org</a><br><br>List Address: <a href="mailto:RE-wrenches@lists.re-wrenches.org">RE-wrenches@lists.re-wrenches.org</a><br><br>Change listserver email address & settings:<br><a href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org" target="_blank">http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org</a><br><br>There are two list archives for searching. When one doesn't work, try the other:<br><a href="https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/" target="_blank">https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/</a><br><a href="http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org" target="_blank">http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org</a><br><br>List rules & etiquette:<br><a href="http://www.re-wrenches.org/etiquette.htm" target="_blank">http://www.re-wrenches.org/etiquette.htm</a><br><br>Check out or update participant bios:<br><a href="http://www.members.re-wrenches.org" target="_blank">http://www.members.re-wrenches.org</a></span></p></div></blockquote></div></div><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Verdana","sans-serif""> </span></p><div><p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-family:"Verdana","sans-serif"">_______________________________________________<br>List sponsored by Redwood Alliance<br><br>Pay optional member dues here: <a href="http://re-wrenches.org" target="_blank">http://re-wrenches.org</a><br><br>List Address: <a href="mailto:RE-wrenches@lists.re-wrenches.org">RE-wrenches@lists.re-wrenches.org</a><br><br>Change listserver email address & settings:<br><a href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org" target="_blank">http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org</a><br><br>There are two list archives for searching. When one doesn't work, try the other:<br><a href="https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/" target="_blank">https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/</a><br><a href="http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org" target="_blank">http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org</a><br><br>List rules & etiquette:<br><a href="http://www.re-wrenches.org/etiquette.htm" target="_blank">http://www.re-wrenches.org/etiquette.htm</a><br><br>Check out or update participant bios:<br><a href="http://www.members.re-wrenches.org" target="_blank">http://www.members.re-wrenches.org</a></span></p></div></blockquote></div></div></div></div></body></html>