Hi Wayne, Why not 12 cells (24VDC) and put the 13th in storage as DRY?
Regards, Jamie >>> Wayne Irwin <wa...@pureenergysolar.com> 5/31/2011 9:01 PM >>> 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. B) On the other hand, Tom presents the exact reason behind the idea of the 3 - string design. This is an off grid system. I know this may open up a can of (philosophically varied) worms. But, this is the reasoning behind the two designs. PS. Buss bars (if 3 strings) and 4/0 CU would be used. Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com ( mailto:pureenergyso...@hotmail.com ) http://pureenergysolar.com ( http://pureenergysolar.net/ ) 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell 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. From: t...@wagonmaker.com To: re-wrenches@lists.re-wrenches.org Date: Tue, 31 May 2011 13:36:16 -1000 Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison .ExternalClass .ecxhmmessage P {padding:0px;} .ExternalClass body.ecxhmmessage {font-size:10pt;font-family:Tahoma;} >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. Tom From: Wayne Irwin ( mailto:wa...@pureenergysolar.com ) Sent: Tuesday, May 31, 2011 11:49 AM To: Wrenches ( mailto:re-wrenches@lists.re-wrenches.org ) Subject: [RE-wrenches] 24 volt Battery Bank comparison Hello Esteemed Battery Gurus, Which of the following do you believe is the better 24 V battery bank? A) 13 - Rolls 2-YS-31 2430 AH @ 20 HR (one string) or B) 9 - Rolls 8-CS-25P 820 AH @ 20 HR (3 strings of 3) Thank you in advance for your input! Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 mailto:pureenergyso...@hotmail.com http://pureenergysolar.com ( http://pureenergysolar.net/ ) 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell 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. _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1375 / Virus Database: 1509/3671 - Release Date: 05/31/11 _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org This email and its attachments have been scanned by iConnection E-Mail Firewall for viruses, spam, and malicious content. The information transmitted in this email is intended only for the entity or person to which it is addressed and may contain confidential/privileged material. If you received this in error, please contact the sender and delete the material from any computer. Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is strictly prohibited. %^^%
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