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<font face="Arial" size="3">Hi Wayne,</font> </p>
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<font face="Arial" size="3">Why not 12 cells (24VDC) and put the 13th in storage as DRY?</font> </p>
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<font face="Arial" size="3">Regards,</font> </p>
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<font face="Arial" size="3">Jamie</font><br><br>>>> Wayne Irwin <wayne@pureenergysolar.com> 5/31/2011 9:01 PM >>><br> A) With a 13th battery and only one string, if there were a failure in one of the cells, the system would most likely demonstrate the failure rather quickly and allow for the faulty battery to be removed while still maintaining adequate voltage to operate the 24V system.<br><br> B) On the other hand, Tom presents the exact reason behind the idea of the 3 - string design.<br><br>This is an off grid system.<br><br>I know this may open up a can of (philosophically varied) worms. But, this is the reasoning behind the two designs.<br><br>PS. Buss bars (if 3 strings) and 4/0 CU would be used.<br><br><br><br><font color="#76923c">Wayne Irwin, EE<br style="color: #76923c">Director of Engineering<br style="color: #76923c">Pure Energy Solar International Inc. <br style="color: #76923c">State Licensed Solar Contractor<br style="color: #76923c">License # CVC56695 </font><br><a href="mailto:PureEnergySolar@hotmail.com">Wayne@PureEnergySolar.com</a><br><a href="http://pureenergysolar.net/" target="_blank">http://pureenergysolar.com</a><br><font color="#76923c">352 377-6527 Office<br style="color: #76923c">352 336-3299 Fax<br style="color: #76923c">352 316-1637 Cell</font><br> </p>
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From: tom@wagonmaker.com<br>To: re-wrenches@lists.re-wrenches.org<br>Date: Tue, 31 May 2011 13:36:16 -1000<br>Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison<br><br>.ExternalClass .ecxhmmessage P {padding:0px;} .ExternalClass body.ecxhmmessage {font-size:10pt;font-family:Tahoma;} </p>
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From a reliability standpoint I would never want to bet the farm on one string. All it takes is the failure of one cell and the system is useless until it is replaced. Three strings means a cell failure only reduces capacity by 33% not 100%. I’ve always thought in off-grid systems it is a good idea to build in as much redundancy as possible whenever possible. Oh, and always use a buss bar system with multiple strings, it makes for a far more stable system with less stress on the batteries. </p>
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Tom </p>
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<b>From:</b> <a title="wayne@pureenergysolar.com" href="mailto:wayne@pureenergysolar.com">Wayne Irwin</a> </p>
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<b>Sent:</b> Tuesday, May 31, 2011 11:49 AM </p>
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<b>To:</b> <a title="re-wrenches@lists.re-wrenches.org" href="mailto:re-wrenches@lists.re-wrenches.org">Wrenches</a> </p>
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<b>Subject:</b> [RE-wrenches] 24 volt Battery Bank comparison </p>
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Hello Esteemed Battery Gurus,<br><br>Which of the following do you believe is the better 24 V battery bank?<br><br>A) 13 - Rolls 2-YS-31 2430 AH @ 20 HR (one string)<br><br>or<br><br>B) 9 - Rolls 8-CS-25P 820 AH @ 20 HR (3 strings of 3)<br><br>Thank you in advance for your input!<br><br><br><font color="#76923c">Wayne Irwin, EE<br style="color: #76923c">Director of Engineering<br style="color: #76923c">Pure Energy Solar International Inc. <br style="color: #76923c">State Licensed Solar Contractor<br style="color: #76923c">License # CVC56695 </font><br><a href="mailto:PureEnergySolar@hotmail.com">mailto:PureEnergySolar@hotmail.com</a><br><a href="http://pureenergysolar.net/" target="_blank">http://pureenergysolar.com</a><br><font color="#76923c">352 377-6527 Office<br style="color: #76923c">352 336-3299 Fax<br style="color: #76923c">352 316-1637 Cell</font><br> </p>
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