<html><body bgcolor="#FFFFFF"><div>Just another thought- If redundancy is an issue with string sizing, having a 12v inverter handy is sometimes a viable backup option with a 24v bank with 2 or more parallel strings. </div><div><br>Jason Szumlanski</div><div>Fafco Solar</div><div><br>On May 31, 2011, at 7:55 PM, "Jason Szumlanski" <<a href="mailto:Jason@fafcosolar.com">Jason@fafcosolar.com</a>> wrote:<br><br></div><div></div><blockquote type="cite"><div><div>If the choice is one or three, I choose one. If the choice is one or two, I choose two for the same redundancy benefit echoed by others. However, it sometimes depends how remote the system is. </div><div><br></div><div>If you are a few miles down the road from a stocking battery distributor, one string is great. If you are a boat ride or a 10 hour 4x4 crawl at 2 mph away, redundancy may be critical. It all depends on the situation. I would even consider three strings if the location has serious access problems and the customer can only "survive" with 33% capacity loss for a period of time.</div><div><br></div><div>While I have my favorite brands, sometimes you have to go with a brand that fits the right capacity and string arrangement. Fortunately Rolls has lots of options, so you should find a suitable alternative. I start with my desired V, aH, and parallel strings, then let the manufacturer or distributor do the work and recommend options. Not that I don't do my research, but sometimes they come up with a better option than you initially think of. <br><br>Jason Szumlanski</div><div>Fafco Solar</div><div><br>On May 31, 2011, at 6:25 PM, "Brian Mehalic" <<a href="mailto:brian@solarenergy.org"><a href="mailto:brian@solarenergy.org">brian@solarenergy.org</a></a>> wrote:<br><br></div><div></div><blockquote type="cite"><div>Hi Wayne-<div>While I think a lot of folks will agree that a single string is better for the long term health of the batteries as it results in more even charging, I still like the idea of at least two strings. That way if a single battery fails, that string can be removed and the end-user can at least get by on half of the pack until a replacement can be installed.</div>
<div>Brian<br><br><div class="gmail_quote">On Tue, May 31, 2011 at 10:19 PM, James Surrette <span dir="ltr"><<a href="mailto:james@surrette.com"></a><a href="mailto:james@surrette.com"><a href="mailto:james@surrette.com">james@surrette.com</a></a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
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<font face="Arial" size="3">Hi Wayne,</font> </p>
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<font face="Arial" size="3">I look forward to the input from the wrenches.</font> </p>
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<font face="Arial" size="3">My recommendation, regardless of the brand, would be for one string.</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 <<a href="mailto:wayne@pureenergysolar.com" target="_blank"></a><a href="mailto:wayne@pureenergysolar.com"><a href="mailto:wayne@pureenergysolar.com">wayne@pureenergysolar.com</a></a>> 5/31/2011 6:49 PM >>><br>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" target="_blank"></a><a href="mailto:Wayne@PureEnergySolar.com"><a href="mailto:Wayne@PureEnergySolar.com">Wayne@PureEnergySolar.com</a></a><br><a href="http://pureenergysolar.net/" target="_blank"></a><a href="http://pureenergysolar.com"><a href="http://pureenergysolar.com">http://pureenergysolar.com</a></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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<br></blockquote></div><br><br clear="all"><br>-- <br>========================<br>Brian Mehalic <br>NABCEP Certified Solar PV Installer™ R031508-59<div>IREC ISPQ Certified Affiliated Instructor/PV US-0132<br><div>PV Curriculum Developer and Instructor<div>
Solar Energy International<br>Carbondale, CO 81623<br><a href="http://www.solarenergy.org" target="_blank"></a><a href="http://www.solarenergy.org"><a href="http://www.solarenergy.org">http://www.solarenergy.org</a></a></div></div></div><br>
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