<html><head><base href="x-msg://48/"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Oops! Guess I should have read all the posts before I reply;-><div><br><div>
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div>Larry Crutcher</div></span><br class="Apple-interchange-newline">
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<br><div><div>On May 31, 2011, at 5:23 PM, Wayne Irwin wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div class="hmmessage" style="font-size: 10pt; font-family: Tahoma; ">I think the verdict is<b><span class="Apple-converted-space"> </span>12</b><span class="Apple-converted-space"> </span>- 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.<span class="Apple-converted-space"> </span></font><font color="#76923c"><br></font><font color="#76923c"></font><font color="#76923c">State Licensed Solar Contractor</font><font color="#76923c"><br></font><font color="#76923c">License # CVC56695<span class="Apple-converted-space"> </span></font><br><a href="mailto:PureEnergySolar@hotmail.com">Wayne@PureEnergySolar.com</a><span class="Apple-converted-space"> </span><br><a href="http://pureenergysolar.net/" target="_blank">http://pureenergysolar.com</a><span class="Apple-converted-space"> </span><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><br><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; "><font color="#76923c"><span style="font-size: 10pt; font-family: Arial, sans-serif; ">The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you.</span></font></div><br><br><br><br><hr id="stopSpelling">Date: Tue, 31 May 2011 18:16:56 -0600<br>From:<span class="Apple-converted-space"> </span><a href="mailto:allan@positiveenergysolar.com">allan@positiveenergysolar.com</a><br>To:<span class="Apple-converted-space"> </span><a href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</a><br>Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison<br><br>Tom,<br>Yes, but if you use individual 2V cells, you can pull one failed cell out of the string and get by just fine by adjusting setpoints down by 8% (11/12ths). You'll lose 8% of capacity until a cell is replaced; or, if the failed cell is the first to go at end-of-life, just live with the remaining 22V bank while collecting funds for the replacement set ("You have been setting aside some money each year for that set, haven't you?").<span class="Apple-converted-space"> </span><br><br>Using two strings is fine, but if the smaller strings are made up of 4V or 6V cases, you no longer can remove just one cell. Rather, you must disconnect one string and live on 50% capacity (or 67% with two out of three strings) until a replacement is secured.<span class="Apple-converted-space"> </span><br><br>Based on the above, I'd usually go with a single string of the best batteries I can find. Personally, I like what Chris Worcester wrote:<br><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; "><span style="font-size: 11pt; font-family: Calibri, sans-serif; color: rgb(31, 73, 125); ">My one string of 1476 AH IBE 2 V cells went 19 years before retiring them to a neighbor’s off grid system, where they are now working. One string has my vote!</span></div><span style="font-size: 10pt; font-family: Calibri, sans-serif; color: navy; "></span>as I just put that exact size of IBE<span style="font-size: 10pt; font-family: Calibri, sans-serif; color: navy; "></span><span class="Apple-converted-space"> </span>2V cells in my own home. Here's hoping I get another 18 years and 10 months out of them.<span class="Apple-converted-space"> </span><br>Allan<br><br><span style="font-size: 10pt; font-family: Calibri, sans-serif; color: navy; "></span><div class="ecxmoz-signature"><font face="Times New Roman, Times, serif"><b>Allan Sindelar</b></font><br><small><a href="mailto:Allan@positiveenergysolar.com"><font color="#000099" face="Times New Roman, Times, serif"><u>Allan@positiveenergysolar.com</u></font></a></small><font face="Times New Roman, Times, serif"><br><span style="font-size: 10pt; ">NABCEP Certified Photovoltaic Installer<br>NABCEP Certified Technical Sales Professional<br>New Mexico EE98J Journeyman Electrician<br><b>Positive Energy, Inc.</b><br>3201 Calle Marie<br>Santa Fe, New Mexico 87507<br><b>505 424-1112</b><br><a href="http://www.positiveenergysolar.com/" target="_blank"><u>www.positiveenergysolar.com</u></a></span></font><span style="font-size: 10pt; "></span></div><br>On 5/31/2011 5:36 PM, Tom Elliot wrote:<blockquote cite="mid:04EB96A325B74AB59657E5E13696937C@Haikulaptop"><div dir="ltr"><div style="font-family: Arial; color: rgb(0, 0, 0); font-size: 10pt; "><div>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.</div><div> </div><div>Tom</div></div></div></blockquote><br>_______________________________________________ List sponsored by Home Power magazine List Address:<span class="Apple-converted-space"> </span><a href="mailto:RE-wrenches@lists.re-wrenches.org">RE-wrenches@lists.re-wrenches.org</a>Options & settings:<span class="Apple-converted-space"> </span><a href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org">http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org</a><span class="Apple-converted-space"> </span>List-Archive:<span class="Apple-converted-space"> </span><a href="http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org">http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org</a><span class="Apple-converted-space"> </span>List rules & etiquette:<span class="Apple-converted-space"> </span><a href="http://www.re-wrenches.org/etiquette.htm">www.re-wrenches.org/etiquette.htm</a><span class="Apple-converted-space"> </span>Check out participant bios:<span class="Apple-converted-space"> </span><a href="http://www.members.re-wrenches.org">www.members.re-wrenches.org</a>_______________________________________________<br>List sponsored by Home Power magazine<br><br>List Address:<span class="Apple-converted-space"> </span><a href="mailto:RE-wrenches@lists.re-wrenches.org">RE-wrenches@lists.re-wrenches.org</a><br><br>Options & settings:<br><a href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org">http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org</a><br><br>List-Archive:<span class="Apple-converted-space"> </span><a href="http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org">http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org</a><br><br>List rules & etiquette:<br><a href="http://www.re-wrenches.org/etiquette.htm">www.re-wrenches.org/etiquette.htm</a><br><br>Check out participant bios:<br><a href="http://www.members.re-wrenches.org">www.members.re-wrenches.org</a><br><br></div></span></blockquote></div><br></div></body></html>