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<p class=MsoNormal><b><font size=2 color=navy face="Comic Sans MS"><span
style='font-size:11.0pt;font-family:"Comic Sans MS";color:navy;font-weight:
bold'>HI Mick,<o:p></o:p></span></font></b></p>
<p class=MsoNormal><b><font size=2 color=navy face="Comic Sans MS"><span
style='font-size:11.0pt;font-family:"Comic Sans MS";color:navy;font-weight:
bold'><o:p> </o:p></span></font></b></p>
<p class=MsoNormal><b><font size=2 color=navy face="Comic Sans MS"><span
style='font-size:11.0pt;font-family:"Comic Sans MS";color:navy;font-weight:
bold'>The Concorde <st1:place w:st="on">Battery</st1:place> web site has a
great technical manual worth checking out; <a
href="http://www.sunxtender.com/pdfs/Sun_Xtender_Battery_Technical_Manual.pdf">www.sunxtender.com/pdfs/Sun_Xtender_Battery_Technical_Manual.pdf</a><o:p></o:p></span></font></b></p>
<p class=MsoNormal><b><font size=2 color=navy face="Comic Sans MS"><span
style='font-size:11.0pt;font-family:"Comic Sans MS";color:navy;font-weight:
bold'><o:p> </o:p></span></font></b></p>
<p class=MsoNormal><b><font size=2 color=navy face="Comic Sans MS"><span
style='font-size:11.0pt;font-family:"Comic Sans MS";color:navy;font-weight:
bold'>It would sound like the this battery bank mostly operating at an average
daily DOD (Depth of Discharge) of about 10% and that daily load will be
increasing to about 20% DOD. <o:p></o:p></span></font></b></p>
<p class=MsoNormal><b><font size=2 color=navy face="Comic Sans MS"><span
style='font-size:11.0pt;font-family:"Comic Sans MS";color:navy;font-weight:
bold'><o:p> </o:p></span></font></b></p>
<p class=MsoNormal><b><font size=2 color=navy face="Comic Sans MS"><span
style='font-size:11.0pt;font-family:"Comic Sans MS";color:navy;font-weight:
bold'> According to the Concorde manual (pg 37) the expected battery life
cycle at 10% DOD is about 5000 cycles. The expect life cycle at 20% DOD is
about 2800 cycles (about 7.6 years). BTW, these values are based on an “End
of Life” when the battery has permanently lost 20% of its original rated
amp-hours. In real life, most batteries stay in service beyond that value.<o:p></o:p></span></font></b></p>
<p class=MsoNormal><b><font size=2 color=navy face="Comic Sans MS"><span
style='font-size:11.0pt;font-family:"Comic Sans MS";color:navy;font-weight:
bold'><o:p> </o:p></span></font></b></p>
<p class=MsoNormal><b><font size=2 color=navy face="Comic Sans MS"><span
style='font-size:11.0pt;font-family:"Comic Sans MS";color:navy;font-weight:
bold'>Obviously, the occasional deeper DOD during cabin visits will somewhat
effect these numbers.<o:p></o:p></span></font></b></p>
<p class=MsoNormal><b><font size=2 color=navy face="Comic Sans MS"><span
style='font-size:11.0pt;font-family:"Comic Sans MS";color:navy;font-weight:
bold'><o:p> </o:p></span></font></b></p>
<p class=MsoNormal><b><font size=2 color=navy face="Comic Sans MS"><span
style='font-size:11.0pt;font-family:"Comic Sans MS";color:navy;font-weight:
bold'>I also agree with Ray’s comments that batteries need to be cycled
somewhat (15% to 20%) to harvest their full life cycle. We all learned that when
we continuously floated battery banks with the old SW inverters. Banks that are
always floated only seem to deliver about 70% of the expected life. Moderate
cycling is good for a battery.<o:p></o:p></span></font></b></p>
<p class=MsoNormal><b><font size=2 color=navy face="Comic Sans MS"><span
style='font-size:11.0pt;font-family:"Comic Sans MS";color:navy;font-weight:
bold'><o:p> </o:p></span></font></b></p>
<p class=MsoNormal><b><font size=2 color=navy face="Comic Sans MS"><span
style='font-size:11.0pt;font-family:"Comic Sans MS";color:navy;font-weight:
bold'>I think increasing the daily DOD from 10% to 20% should not significantly
reduce battery life. This is assuming the batteries get fully recharged on a
regular basis.<o:p></o:p></span></font></b></p>
<p class=MsoNormal><b><font size=2 color=navy face="Comic Sans MS"><span
style='font-size:11.0pt;font-family:"Comic Sans MS";color:navy;font-weight:
bold'><o:p> </o:p></span></font></b></p>
<p class=MsoNormal><b><font size=2 color=navy face="Comic Sans MS"><span
style='font-size:11.0pt;font-family:"Comic Sans MS";color:navy;font-weight:
bold'>Steve<o:p></o:p></span></font></b></p>
<p class=MsoNormal><b><font size=2 color=navy face="Comic Sans MS"><span
style='font-size:11.0pt;font-family:"Comic Sans MS";color:navy;font-weight:
bold'><o:p> </o:p></span></font></b></p>
<div>
<p class=MsoNormal><strong><b><font size=2 color=navy face="Trebuchet MS"><span
style='font-size:10.0pt;font-family:"Trebuchet MS";color:navy'>Steve Bell</span></font></b></strong><font
size=2 color=navy face="Trebuchet MS"><span style='font-size:10.0pt;font-family:
"Trebuchet MS";color:navy'><o:p></o:p></span></font></p>
<p class=MsoNormal><em><i><font size=2 color=navy face="Trebuchet MS"><span
style='font-size:10.0pt;font-family:"Trebuchet MS";color:navy'>Technical
Support Specialist </span></font></i></em><font size=2 color=navy
face="Trebuchet MS"><span style='font-size:10.0pt;font-family:"Trebuchet MS";
color:navy'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face="Trebuchet MS"><span
style='font-size:10.0pt;font-family:"Trebuchet MS";color:navy'> <o:p></o:p></span></font></p>
<p class=MsoNormal><st1:PersonName w:st="on"><strong><b><font size=2
color=navy face="Trebuchet MS"><span style='font-size:10.0pt;font-family:"Trebuchet MS";
color:navy'>SunWize Technologies</span></font></b></strong></st1:PersonName><strong><b><font
size=2 color=navy face="Trebuchet MS"><span style='font-size:10.0pt;font-family:
"Trebuchet MS";color:navy'>, Inc.</span></font></b></strong><font color=navy
face="Trebuchet MS"><span style='font-family:"Trebuchet MS";color:navy'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face="Trebuchet MS"><span
style='font-size:10.0pt;font-family:"Trebuchet MS";color:navy'>#1 Sun Street</span></font><font
color=navy face="Trebuchet MS"><span style='font-family:"Trebuchet MS";
color:navy'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face="Trebuchet MS"><span style='font-size:
10.0pt;font-family:"Trebuchet MS"'><ns0:place w:insAuthor="Steve Bell"
w:insDate="2010-06-10T14:12:00Z" w:endInsAuthor="Steve Bell"
w:endInsDate="2010-06-10T14:12:00Z"><ns0:City w:insAuthor="Steve Bell"
w:insDate="2010-06-10T14:12:00Z" w:endInsAuthor="Steve Bell"
w:endInsDate="2010-06-10T14:12:00Z"><st1:place w:st="on"><st1:City w:st="on"><font
color=navy><span style='color:navy'>Stelle</span></font></st1:City></ns0:City></st1:place><font
color=navy><span style='color:navy'>, </span></font><ns0:State
w:insAuthor="Steve Bell" w:insDate="2010-06-10T14:12:00Z"
w:endInsAuthor="Steve Bell" w:endInsDate="2010-06-10T14:12:00Z"><st1:State
w:st="on"><font color=navy><span style='color:navy'>IL</span></font></st1:State></ns0:State><font
color=navy><span style='color:navy'> </span></font><ns0:PostalCode
w:insAuthor="Steve Bell" w:insDate="2010-06-10T14:12:00Z"
w:endInsAuthor="Steve Bell" w:endInsDate="2010-06-10T14:12:00Z"><st1:PostalCode
w:st="on"><font color=navy><span style='color:navy'>60919</span></font></st1:PostalCode></ns0:PostalCode><font
color=navy><span style='color:navy'> </span></font><ns0:country-region
w:insAuthor="Steve Bell" w:insDate="2010-06-10T14:12:00Z"
w:endInsAuthor="Steve Bell" w:endInsDate="2010-06-10T14:12:00Z"><st1:country-region
w:st="on"><font color=navy><span style='color:navy'>USA</span></font></st1:country-region></ns0:country-region></ns0:place></span></font><font
color=navy face="Trebuchet MS"><span style='font-family:"Trebuchet MS";
color:navy'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face="Trebuchet MS"><span
style='font-size:10.0pt;font-family:"Trebuchet MS";color:navy'>(815) 256-2222
ext. 23</span></font><font color=navy face="Trebuchet MS"><span
style='font-family:"Trebuchet MS";color:navy'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face="Trebuchet MS"><span
style='font-size:10.0pt;font-family:"Trebuchet MS";color:navy'><a
href="mailto:sbell@sunwize.com">sbell@sunwize.com</a></span></font><font
color=navy face="Trebuchet MS"><span style='font-family:"Trebuchet MS";
color:navy'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face="Trebuchet MS"><span
style='font-size:10.0pt;font-family:"Trebuchet MS";color:navy'><a
href="http://www.sunwize.com">www.sunwize.com</a></span></font><o:p></o:p></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
re-wrenches-bounces@lists.re-wrenches.org [mailto:re-wrenches-bounces@lists.re-wrenches.org]
<b><span style='font-weight:bold'>On Behalf Of </span></b>Mick Abraham<br>
<b><span style='font-weight:bold'>Sent:</span></b> Thursday, June 10, 2010
11:02 AM<br>
<b><span style='font-weight:bold'>To:</span></b> RE-wrenches<br>
<b><span style='font-weight:bold'>Subject:</span></b> [RE-wrenches] Help me do
the math: amortized cost per amp-hour</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Greetings, fellow Energy Techs~<br>
<br>
A client has a nice new set of 2v Concorde AGM sealed batteries: 915 amp hours
in one 24 volt string. His cabin is often unoccupied with only the refrigerator
running. During those "idle" days the battery is called upon to
deliver an average of 90 amp hours every night...about 10% discharge.<br>
<br>
The client wishes to rev up some more loads to run during these idle times.
Coincidentally, those loads would also require an additional 10% discharge from
the battery each night. The added loads surely have a cost in terms of
decreased battery lifetime. I wish to do the math to amortize the battery cost
and arrive at a "dollar value per month" for the additional loads.<br>
<br>
The pack plus installation cost about $4,700. I don't know the number of
"lifetime amp-hours" which could be expected from these batts, but <b><i><span
style='font-weight:bold;font-style:italic'>I hope one of you can help me get
that number.</span></i></b> Could we then divide $4,700 by the lifetime
amp-hours to get the cost per amp hour? If so...I could do the rest of the math
from there.<br>
<br>
*************************************************************<br>
<br>
Side note: I realize that various factors such as shallow cycling, repeated
overdischarge, repeated overcharge, etc. can affect the number of amp hours
which any battery can deliver. In this case, let's assume the following:<br>
<br>
* No repeat overcharge because I'm strictly following Concorde recommendations
and I've even calibrated the Outback charge devices<br>
<br>
* No repeat overdischarge because I >finally< have the generator
automation dialed in and reliable (fingers crossed)<br>
<br>
* Prompt recharge after discharge...because there's an OK sized solar array,
many sunny days plus the genset backup<br>
<br>
* Electronic sulfate dissolver is installed on the battery string<br>
<br>
* Average cycle depth of 50% discharge. I'm using this value to factor in the
times when the cabin is occupied and therefore cycling harder on the battery<br>
<br>
* Limited heat stress on the battery. The cells are in a crawl space in alpine
terrain so they will range from cold to cool, never warm<br>
<br>
<br>
**************************************************************<br>
<br>
Thanks in advance for your assistance. The <u>Wrench List</u> is the bomb!<br>
<br clear=all>
Mick Abraham, Proprietor<br>
<a href="http://www.abrahamsolar.com">www.abrahamsolar.com</a><br>
<br>
Voice: 970-731-4675<o:p></o:p></span></font></p>
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