<!DOCTYPE html><html><head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<p>William,</p>
<p>I think that the SOC determined by lithium BMSs come with similar
accuracy issues that occur with the Trimetric, FNDC, Magnum
BMK,... - small measurement errors integrated over a long time
become big errors. That's why Fortress (and every SOC meter) is
saying that the battery needs to reach 54.4 volts once a week for
recalibration. At least with lithium batteries the SOC meter
doesn't need to account for the return current dropping down as is
required with lead-acid batteries. The internal BMSs probably do a
better job of estimating the SOC than these external devices, but
I do not expect them to be perfect. Same goes with everyone's
electric car, while we put a lot of faith in the displayed SOC it
probably isn't much better than ±5% and if it were off by 10% you
probably wouldn't know. <br>
</p>
<p>In regards to your graph showing a big voltage difference between
two 55% SOC occurrences over a 12 hour time frame. I question your
assumption that the voltage should be the same. The data show
different voltages for the same SOC, it seems unlikely that the
BMS measurement drifted by enough to make that happen, so I think
the data shown may both be correct within reason. The voltage of
lithium cells is highly load dependent (probably somewhat
temperature dependent too) so perhaps the Fortress battery is
actually close to right at both times.<br>
</p>
<p>Since using the SI SOC meter for starting the generator is
problematic, an external device for starting based on voltage is a
good idea. If you want a ready to go product to do that, I think
the Morningstar relay driver will work well. A little difficult to
program or reprogram but very reliable. One issue you will observe
is that the generator won't start at a consistent SOC as indicated
by the battery or the SI.<br>
</p>
Kent Osterberg<br>
Blue Mountain Solar
<p><br>
</p>
<div class="moz-cite-prefix">On 2/9/2024 11:27 AM, William Miller
via RE-wrenches wrote:<br>
</div>
<blockquote type="cite" cite="mid:b95f68212dd6ec06b1ae7210377bf28d@mail.gmail.com">
<meta name="Generator" content="Microsoft Word 14 (filtered medium)">
<style>@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}@font-face
{font-family:Consolas;
panose-1:2 11 6 9 2 2 4 3 2 4;}@font-face
{font-family:Verdana;
panose-1:2 11 6 4 3 5 4 4 2 4;}p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}p
{mso-style-priority:99;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:12.0pt;
font-family:"Times New Roman","serif";}pre
{mso-style-priority:99;
mso-style-link:"HTML Preformatted Char";
margin:0in;
margin-bottom:.0001pt;
font-size:10.0pt;
font-family:"Courier New";}p.MsoAcetate, li.MsoAcetate, div.MsoAcetate
{mso-style-priority:99;
mso-style-link:"Balloon Text Char";
margin:0in;
margin-bottom:.0001pt;
font-size:8.0pt;
font-family:"Tahoma","sans-serif";}span.HTMLPreformattedChar
{mso-style-name:"HTML Preformatted Char";
mso-style-priority:99;
mso-style-link:"HTML Preformatted";
font-family:Consolas;}p.v1v1v1msonormal, li.v1v1v1msonormal, div.v1v1v1msonormal
{mso-style-name:v1v1v1msonormal;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:12.0pt;
font-family:"Times New Roman","serif";}p.v1v1v1msoacetate, li.v1v1v1msoacetate, div.v1v1v1msoacetate
{mso-style-name:v1v1v1msoacetate;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:12.0pt;
font-family:"Times New Roman","serif";}p.v1v1v1msochpdefault, li.v1v1v1msochpdefault, div.v1v1v1msochpdefault
{mso-style-name:v1v1v1msochpdefault;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:12.0pt;
font-family:"Times New Roman","serif";}span.v1v1v1msohyperlink
{mso-style-name:v1v1v1msohyperlink;}span.v1v1v1msohyperlinkfollowed
{mso-style-name:v1v1v1msohyperlinkfollowed;}span.v1v1v1emailstyle17
{mso-style-name:v1v1v1emailstyle17;}span.v1v1v1balloontextchar
{mso-style-name:v1v1v1balloontextchar;}p.v1v1v1msonormal1, li.v1v1v1msonormal1, div.v1v1v1msonormal1
{mso-style-name:v1v1v1msonormal1;
margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}span.v1v1v1msohyperlink1
{mso-style-name:v1v1v1msohyperlink1;
mso-style-priority:99;
color:blue;
text-decoration:underline;}span.v1v1v1msohyperlinkfollowed1
{mso-style-name:v1v1v1msohyperlinkfollowed1;
mso-style-priority:99;
color:purple;
text-decoration:underline;}span.BalloonTextChar
{mso-style-name:"Balloon Text Char";
mso-style-priority:99;
mso-style-link:"Balloon Text";
font-family:"Tahoma","sans-serif";}p.v1v1v1msoacetate1, li.v1v1v1msoacetate1, div.v1v1v1msoacetate1
{mso-style-name:v1v1v1msoacetate1;
mso-style-priority:99;
margin:0in;
margin-bottom:.0001pt;
font-size:8.0pt;
font-family:"Tahoma","sans-serif";}span.EmailStyle34
{mso-style-type:personal;
font-family:"Verdana","sans-serif";
color:#1F497D;}span.BalloonTextChar1
{mso-style-name:"Balloon Text Char1";
mso-style-priority:99;
font-family:"Tahoma","sans-serif";}span.EmailStyle37
{mso-style-type:personal-reply;
font-family:"Verdana","sans-serif";
color:#993366;}.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}div.WordSection1
{page:WordSection1;}</style>
<div class="WordSection1">
<p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#993366">Dave:</span></p>
<p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><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"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><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"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#993366"><img id="Picture_x0020_1" src="cid:part1.1eJya5TI.Vp9TQr9z@coveoregon.com" class="" width="773" height="1004"></span><span style="font-family:"Verdana","sans-serif";color:#993366"></span></p>
<p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><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"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><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"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><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"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><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"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><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"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><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"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><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"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#993366">Drake,
thanks for asking.</span></p>
<p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#993366">William</span></p>
<p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#993366">PS:
Brainstorming a solutions here: </span></p>
<p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><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"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><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"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#993366">Ideas,
anyone?</span></p>
<p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#993366">WM</span></p>
<p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<div>
<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#993366">Miller
Solar</span></p>
<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#993366">17395
Oak Road, Atascadero, CA 93422</span></p>
<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#993366">805-438-5600</span></p>
<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#993366"><a href="http://www.millersolar.com/" moz-do-not-send="true"><span style="color:blue">www.millersolar.com</span></a></span></p>
<p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:#993366">CA
Lic. 773985</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#993366"> </span></p>
</div>
<p class="MsoNormal"><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"><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" moz-do-not-send="true" class="moz-txt-link-freetext">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"> </p>
<div id="v1_rc_sig">
<p class="MsoNormal"><span style="font-family:"Verdana","sans-serif"">Hi Drake,</span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-family:"Verdana","sans-serif""> </span></p>
</div>
<div>
<p class="MsoNormal"><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"><span style="font-family:"Verdana","sans-serif""> </span></p>
</div>
<div>
<p class="MsoNormal"><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" moz-do-not-send="true"> </a><a href="https://offgridsolar1.com/" target="_blank" moz-do-not-send="true"><span style="font-family:"Verdana","sans-serif";background:white;font-weight:normal">https://offgridsolar1.com/</span></a><a href="http://members.sti.net/offgridsolar/" target="_blank" moz-do-not-send="true"> </a></span></strong></pre>
<pre><strong><span style="font-size:12.0pt;font-family:"Courier New"">e-mail <a href="mailto:offgridsolar@sti.net" moz-do-not-send="true" class="moz-txt-link-freetext">offgridsolar@sti.net</a></span></strong></pre>
<pre><strong><span style="font-size:12.0pt;font-family:"Courier New"">text 209 813 0060</span></strong></pre>
</div>
<p><span style="font-family:"Verdana","sans-serif""> </span></p>
<p id="v1reply-intro"><span style="font-family:"Verdana","sans-serif"">On
2024-02-09 8:05 am, Drake Chamberlin via RE-wrenches wrote:</span></p>
<blockquote style="border:none;border-left:solid #1010ff 1.5pt;padding:0in 0in 0in 5.0pt;margin-left:0in;margin-right:0in">
<div id="v1replybody1">
<div>
<p><span style="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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></span></p>
</div>
<p><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""> </span></p>
<p id="v1v1reply-intro"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">On
2024-02-05 11:36, William Miller via RE-wrenches
wrote:</span></p>
<blockquote style="border:none;border-left:solid #1010ff 1.5pt;padding:0in 0in 0in 5.0pt;margin-left:0in;margin-right:0in">
<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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></span></p>
<p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""><b>Error!
Filename not specified.</b><b>Error!
Filename not specified.</b><span style="color:#1f497d"><b>Error! Filename not
specified.</b></span></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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></span></p>
<p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1f497d">805-438-5600</span><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""></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" moz-do-not-send="true">www.millersolar.com</a></span><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></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;font-family:"Verdana","sans-serif""></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" moz-do-not-send="true" class="moz-txt-link-freetext">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;font-family:"Verdana","sans-serif""></span></p>
<p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""> </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></p>
<div>
<p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""> </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></p>
<div>
<p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""> </span></p>
</div>
<div>
<p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">Jason
Szumlanski</span></p>
</div>
<div>
<p class="v1v1v1msonormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">Florida
Solar Design Group </span></p>
</div>
</div>
</div>
</div>
</div>
</div>
<span style="white-space: pre-wrap">
</span></blockquote>
</div>
</div>
</blockquote>
</div>
<pre class="moz-quote-pre" wrap="">
</pre>
</blockquote>
</body>
</html>