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<DIV>Bob,</DIV>
<DIV> </DIV>
<DIV>I totally understand the concern about multiple strings *if the strings are
connected across the battery bank* as had always been the tradition in off-grid
installations. My own experience with such a bank in my system
showed why when I had a single cell get to near meltdown. I was lucky to
find it. Maintenance is another reason, such banks are far more difficult
to maintain. But I think those concerns are ameliorated a great deal with
a buss bar installation and once I did that I never had another problem and
found the battery bank much easier to maintain because the strings no longer had
to be right next to each other. Heck, it would be possible to put each
series string in its own box for that matter. And with the inclusion of
string fuses that reduces problems even further. </DIV>
<DIV> </DIV>
<DIV>When living with an off-grid system my biggest concern was system
reliability and redundancy and the idea of a single string failure was a big
worry which is why I never would consider it.</DIV>
<DIV> </DIV>
<DIV>Tom</DIV>
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<DIV style="font-color: black"><B>From:</B> <A title=boB@midnitesolar.com
href="mailto:boB@midnitesolar.com">boB Gudgel</A> </DIV>
<DIV><B>Sent:</B> Tuesday, May 31, 2011 8:16 PM</DIV>
<DIV><B>To:</B> <A title=re-wrenches@lists.re-wrenches.org
href="mailto:re-wrenches@lists.re-wrenches.org">RE-wrenches</A> </DIV>
<DIV><B>Subject:</B> Re: [RE-wrenches] 24 volt Battery Bank
comparison</DIV></DIV></DIV>
<DIV> </DIV></DIV>
<DIV
style="FONT-STYLE: normal; DISPLAY: inline; FONT-FAMILY: 'Calibri'; COLOR: #000000; FONT-SIZE: small; FONT-WEIGHT: normal; TEXT-DECORATION: none"><BR><BR>OK,
I've been hearing for years now that one battery string is best and maybe two
but no more should be used.<BR><BR>What is the reason for this fear
??? What is the experience with multiple strings in parallel
??<BR><BR>If it is because of current sharing of the strings, that shouldn't be
an insurmountable problem if the wiring is done right.<BR><BR>If it has to do
with the possibility of fire, which Darryl mentioned, seems that series string
fuses could mitigate the possibility of that issue, if because of shorted cells,
just like PV combiners.<BR><BR>Or maybe it has to do with the trouble of getting
into the middle of a pile of batteries ? Use battery boxes ?<BR><BR>The
strings are in parallel and so they all get the same voltage, theoretically
anyway if the connections are good.<BR><BR>I would think that the more strings,
the LESS stress on individual batteries, not more. The current in each
battery should be less than it would be I would think.<BR><BR>So what is the
real experience ?? <BR><BR>Is a battery balancer the answer
??<BR><BR>Thanks,<BR>boB<BR><BR><BR><BR><BR><BR>
<BLOCKQUOTE cite=mid:C956D9BB-02FF-4821-9909-AF40789AFBF1@fafcosolar.com
type="cite">
<DIV><BR>On May 31, 2011, at 8:23 PM, "Wayne Irwin" <<A
href="mailto:wayne@pureenergysolar.com"
moz-do-not-send="true">wayne@pureenergysolar.com</A>> wrote:<BR><BR></DIV>
<BLOCKQUOTE type="cite">
<DIV>I think the verdict is<B> 12</B> - Rolls 2-YS-31 2430 AH @ 20 HR (one
string) and one dry spare in storage is the best case scenario!<BR><BR><FONT
color=#76923c>Wayne Irwin</FONT><FONT color=#76923c>, EE<BR>Director of
Engineering<BR></FONT><FONT color=#76923c>Pure Energy Solar International
Inc. </FONT><FONT color=#76923c><BR></FONT><FONT color=#76923c>State
Licensed Solar Contractor</FONT><FONT color=#76923c><BR></FONT><FONT
color=#76923c>License # CVC56695 </FONT><BR><A
href="mailto:Wayne@PureEnergySolar.com"
moz-do-not-send="true">Wayne@PureEnergySolar.com</A> <BR><A
href="http://pureenergysolar.com"
moz-do-not-send="true">http://pureenergysolar.com</A> <BR><FONT
color=#76923c>352 377-6527 Office</FONT><FONT color=#76923c><BR></FONT><FONT
color=#76923c>352 336-3299 Fax</FONT><FONT color=#76923c><BR></FONT><FONT
color=#76923c>352 316-1637 Cell</FONT></DIV></BLOCKQUOTE></BLOCKQUOTE><BR>
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