<div dir="ltr">Jeff, <div><br></div><div>This has to do with testing... it takes a lot of time to do real cycle life testing even if you are doing accelerated testing. <br><br>Some of the Lithium manufacturers that claim 8000 -10,000+ cycles at 80-100% DOD I think are not being .... well you know... <br><br>I personally think they are oversizing the cells to ensure that a 100% DOD cycle is just 60-80% DOD... <br><br>Just to give you an idea, we incorporated some changes into our batteries last year that we had been working on since 2015. By adding carbon to the S4500 and S5000 batteries by June of 2019 we had simulated over 4000 cycles on the Series 5000's. By the time we released the product we had already done 4 years of testing to verify operation with multiple testing partners. We are still testing those batteries today to determine their true failure point and cycle lives... <br><br>The hard part is what is a cycle, and controlling the depth of discharge for every single cycle. With LFP you have an onboard computer that keeps track of all the power in and out, what discover is doing is a smart thing to do, they are keeping track of the total power in and out and using that for warranty. <br><br>Battery warranties are much like panel warranties, especially with Lithium... You will lose some capacity right out of the gate, but the warranty is usually 70-80% of capacity for "X" amount of cycles or thruput power. I kind of like the way Discover is doing their warranties, as to how do you prove that someone has over cycled their battery bank? </div><div><br></div><div><br></div><div><br clear="all"><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div style="float:left;padding:1px 10px 0 0"><a href="http://www.rollsbattery.com" target="_blank"></a><a href="http://www.rollsbattery.com" target="_blank"></a><a href="http://www.rollsbattery.com" target="_blank"></a><a href="http://www.rollsbattery.com" target="_blank"></a><a href="http://www.rollsbattery.com" target="_blank"></a><a href="http://www.rollsbattery.com" target="_blank"></a><a href="http://www.rollsbattery.com" target="_blank"></a><a href="http://www.rollsbattery.com" target="_blank"></a><a href="http://www.rollsbattery.com" target="_blank"></a><a href="http://www.rollsbattery.com" target="_blank"></a><a href="http://www.rollsbattery.com" target="_blank"></a><a href="http://www.rollsbattery.com" target="_blank"></a><a href="http://www.rollsbattery.com" target="_blank"></a><a href="http://www.rollsbattery.com" target="_blank"></a><a href="http://www.rollsbattery.com" target="_blank"></a><a href="http://www.rollsbattery.com" target="_blank"><img src="https://imgur.com/hENEoQQ.png" alt="" style="padding:3px 0px 0px 10px;float:left;margin-right:10px;width:98px;height:115px"></a><div style="font-style:normal;font-variant:normal;font-weight:bold;font-stretch:normal;font-size:14px;line-height:20px;font-family:Arial,Helvetica,sans-serif;margin:0px"><font color="#bb1a1d">Steve Higgins \u22c5
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<div bgcolor="#FFFFFF">Hey All,<br>
<br>
Great Thread - so does anyone have the missing cycle life information
for the Discover AES and Fortress Eflex below?<br>
<br>
<ul>
<li>Discover AES (42-48-6650) (Spec sheet does not list cycles) (but
does give 38MWh warranty</li>
</ul>
see analysis sheet here: <a href="https://aeesolar.com/wp-content/uploads/2019/02/DISCOVER-AES-The-AES-LiFePO-Battery-Solar-Off-grid-Advantage-20190124-AEE.pdf" target="_blank">https://aeesolar.com/wp-content/uploads/2019/02/DISCOVER-AES-The-AES-LiFePO-Battery-Solar-Off-grid-Advantage-20190124-AEE.pdf</a><br>
<br>
that sheet says "With a designed DOD of 50% lead-acid batteries are
expected to last ~1500 cycles or 4 Years of daily cycling.
With the Discover AES 10 Year 38 MWh Warranty, you\u2019ll be half way into
your 3rd Set of lead-acid batteries."<br>
<br>
That would imply 5250 cycles under warranty - but surely it has more in
it than that for an expensive LFP! Can't find a reference anywhere. 38
MWH/6.65 KWH = 5700 cycles - their own spreadsheet says "Cycle Life
(@DOD rating): NA" Impressive warranty but how much past the warranty
they don't seem to want to venture. It's the most expensive of the
options listed here (well comparable to BI) and comes with highest
quality recommendation and has great closed loop communications - but
would love to know the top end cycle figure.<br>
<br>
<ul>
<li>Fortress EVault (18KWH) (Spec sheet says 6000)</li>
<li>Fortress EFlex (5.4 KWH) ( Spec sheet does not list cycles)</li>
<li>Simpliphi 3.8 (spec sheet says 10,000+ @ 80%)</li>
<li>Blue Ion 2.0 spec sheet says 8000 @ 100% DOD</li>
</ul>
<p>Does anyone know why Simpliphi and BI an claim such high cycle life
whereas Fortress says 6000 and AES won't venture it? same chemistry?
so is Fortress underselling or the other folks over selling?<br>
</p>
Has anyone even seen a curve of cycle life vs. DOD for LFP? or is that
not so much a curve as a flat line?<br>
<br>
thanks!<br>
<br>
Jeff<br>
<br>
~~~~~~~~~~~<br>
<span>Jeff Clearwater<br></span><span><span>VillageLab<br>
</span>Village Power Design</span><span><span><span><br>
</span></span><a href="http://www.villagelab.net" target="_blank">www.villagelab.net</a></span><br>
<span><span><a href="http://www.villagepowerdesign.com" target="_blank">www.villagepowerdesign.com</a></span><br>
cell - <span style="display:inline;font-size:inherit;padding:0px;color:rgb(80,80,80)">413-559-9763<br>
~~~~~~~~~~~~~~~~~~~~~~~</span></span><br>
<br>
<br>
<br>
<br>
<span>Richard Scott wrote on 8/11/20 10:35 AM:</span><br>
<blockquote type="cite">
<div dir="ltr">Also keep in mind that the battery charge/discharge
efficiency is much higher for lithium batteries compared to lead acid.<div><br></div><div>Richard</div><div><br></div></div>
<br>
<div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Aug
11, 2020 at 8:17 AM Jay <<a href="mailto:jay.peltz@gmail.com" target="_blank">jay.peltz@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="auto"><div dir="ltr">Hi
William,</div><div dir="ltr"><br></div><div dir="ltr">I dont do the
math based on up front kwh cost, but on lifetime kWh based on the number
of cycles per average DOD that are going to be used. I use this same
formula to compare all batteries to each other. </div><div dir="ltr"><br></div><div dir="ltr">Jay</div><div dir="ltr"><br></div><div dir="ltr">Peltz
power. </div><div dir="ltr"><br></div><div dir="ltr">For example, a
Rolls L16 ex has 3500 cycles at 50% DOD, and it\u2019s a 371 amp hr at 6v or
2.226 kWh </div><div dir="ltr">Retail is $400 </div><div dir="ltr"><br></div><div dir="ltr">3500 cycles x 1.1 kWh At 50 DOD=3850 kWh </div><div dir="ltr">$400
/ 3850 kWh = $.10 kWh </div><div dir="ltr">10 years of 50% cycling
daily </div><div dir="ltr"><br></div><div dir="ltr">Compared to say a
mid grade US battery, 1400 cycles to 50%, 400 amp hr. 2.4 kWh </div><div dir="ltr">$325/1680 kWh = $.19 kWh. </div><div dir="ltr">3.8 yrs life</div><div dir="ltr"><br></div><div dir="ltr">Compare to say BI</div><div dir="ltr">$1000 kWh roughly. </div><div dir="ltr">If you get 10,000
cycles, that works out to same cost. $.10 per kWh. </div><div dir="ltr">27
yrs, but will the chemistry actually last that long?</div><div dir="ltr">However, you have a massive upfront money cost. </div><div dir="ltr">And for those of us off grid, you can\u2019t really cycle 100%. And
many lithium in the fine print don\u2019t want you to charge to 100% daily.
Let\u2019s assume you start the generator at 10% and charge to 95%, now your
usable amount is actually 85%, not 100%. </div><div dir="ltr">Cost per
kWh goes to $.12. </div><div dir="ltr"><br></div><div dir="ltr"><br></div><div dir="ltr"><br></div><div dir="ltr"><br></div><div dir="ltr"><blockquote type="cite">On Aug 11, 2020, at 6:04 AM, William Miller <<a href="mailto:william@millersolar.com" target="_blank">william@millersolar.com</a>> wrote:<br><br></blockquote></div><blockquote type="cite"><div dir="ltr">\ufeff<div><p class="MsoNormal"><span style="font-family:Verdana,sans-serif;color:rgb(31,73,125)">Friends:</span></p><p class="MsoNormal"><span style="font-family:Verdana,sans-serif;color:rgb(31,73,125)"> </span></p><p class="MsoNormal"><span style="font-family:Verdana,sans-serif;color:rgb(31,73,125)">I am hoping
y\u2019all can tell me I am doing something wrong with my arithmetic. I have
registered to purchase Blue Planet batteries and priced the product. I
come up with math that indicates that comparing usable amp/hours to
usable amp/hours, that the Blue Planet is 5 times the cost of a flooded
L-16 battery array on a cost per kilowatt/hour. Can this be true?</span></p><p class="MsoNormal"><span style="font-family:Verdana,sans-serif;color:rgb(31,73,125)"> </span></p><p class="MsoNormal"><span style="font-family:Verdana,sans-serif;color:rgb(31,73,125)">I am using
these parameters:</span></p><p class="MsoNormal"><span style="font-family:Verdana,sans-serif;color:rgb(31,73,125)"> </span></p><p style="margin-left:0.75in"><span style="font-family:Verdana,sans-serif;color:rgb(31,73,125)"><span>1.<span style="font:7pt "Times New Roman""> </span></span></span><span style="font-family:Verdana,sans-serif;color:rgb(31,73,125)">DOD for
flooded L16s: 50%</span></p><p style="margin-left:0.75in"><span style="font-family:Verdana,sans-serif;color:rgb(31,73,125)"><span>2.<span style="font:7pt "Times New Roman""> </span></span></span><span style="font-family:Verdana,sans-serif;color:rgb(31,73,125)">DOD for
Blue Planet: 100%</span></p><p class="MsoNormal"><span style="font-family:Verdana,sans-serif;color:rgb(31,73,125)"> </span></p><p class="MsoNormal"><span style="font-family:Verdana,sans-serif;color:rgb(31,73,125)">I hope I am
wrong.</span></p><p class="MsoNormal"><span style="font-family:Verdana,sans-serif;color:rgb(31,73,125)"> </span></p><p class="MsoNormal"><span style="font-family:Verdana,sans-serif;color:rgb(31,73,125)">Also, we
often install battery arrays that are upwards of 4,000 AH. For example,
we installed 5,668 of East Penn flooded batteries on a couple of
projects. To acquire the same capacity in Blue Planet would require 9
cabinets (again 50% DOD versus 100% DOD). Is this correct design? Is
it practical to install 9 cabinets? Does the system detect and
compensate for circulating currents in this many parallel strings?</span></p><p class="MsoNormal"><span style="font-family:Verdana,sans-serif;color:rgb(31,73,125)"> </span></p><p class="MsoNormal"><span style="font-family:Verdana,sans-serif;color:rgb(31,73,125)">Thanks in
advance.</span></p><p class="MsoNormal"><span style="font-family:Verdana,sans-serif;color:rgb(31,73,125)"> </span></p><p class="MsoNormal"><span style="font-family:Verdana,sans-serif;color:rgb(31,73,125)">William
Miller</span></p><p class="MsoNormal"><span style="font-family:Verdana,sans-serif;color:rgb(31,73,125)"> </span></p><p class="MsoNormal"><span style="font-family:Verdana,sans-serif;color:rgb(31,73,125)"> </span></p><p class="MsoNormal"><b><span style="font-size:10pt;font-family:Tahoma,sans-serif">From:</span></b><span style="font-size:10pt;font-family:Tahoma,sans-serif"> RE-wrenches
[mailto:<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">re-wrenches-bounces@lists.re-wrenches.org</a>]
<b>On Behalf Of </b>Jerry Shafer<br><b>Sent:</b> Sunday, August 9, 2020
12:02 PM<br><b>To:</b> RE-wrenches<br><b>Subject:</b> Re: [RE-wrenches]
Best Battery</span></p><p class="MsoNormal"> </p><div><p class="MsoNormal">Wrenchel have been very happy with all my Blue Planet
battery systems, best battery you will install.</p><div><p class="MsoNormal">Jerry</p></div></div><p class="MsoNormal"> </p><div><div><p class="MsoNormal">On Sun, Aug 9, 2020, 11:19 AM <<a href="mailto:drake.chamberlin@redwoodalliance.org" target="_blank">drake.chamberlin@redwoodalliance.org</a>>
wrote:</p></div><blockquote style="border-top:none;border-right:none;border-bottom:none;border-left:1pt solid rgb(204,204,204);padding:0in 0in 0in 6pt;margin-left:4.8pt;margin-right:0in"><p class="MsoNormal" style="margin-bottom:12pt">Hello Wrenches,<br><br>What is the best
Li-Ion battery to use with an off grid system?<br><br>Thanks,<br><br>Drake<br>Athens
Electric<br><br>-- <br>_______________________________________________<br>List
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<br>
<div>-- <br><span>~~~~~~~~~~~<br>
</span>
<div>
<span>Jeff Clearwater</span><span><span><br>
</span>Village Power Design<br>
</span><span><span><span><a href="https://www.linkedin.com/in/jeff-clearwater-0622a312/" target="_blank">linkedin</a>
</span></span></span><br>
<span><span><a href="http://www.villagepowerdesign.com" target="_blank">www.villagepowerdesign.com</a></span><br>
cell - <span style="display:inline;font-size:inherit;padding:0px;color:rgb(80,80,80)">413-559-9763<br>
~~~~~~~~~~~~~~~~~~~~~~~</span></span></div>
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