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.
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. 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. Jason Szumlanski Fafco Solar On May 31, 2011, at 6:25 PM, "Brian Mehalic" <br...@solarenergy.org> wrote: > Hi Wayne- > 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. > Brian > > On Tue, May 31, 2011 at 10:19 PM, James Surrette <ja...@surrette.com> wrote: > Hi Wayne, > > I look forward to the input from the wrenches. > > My recommendation, regardless of the brand, would be for one string. > > Regards, > > Jamie > > >>> Wayne Irwin <wa...@pureenergysolar.com> 5/31/2011 6:49 PM >>> > 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 > wa...@pureenergysolar.com > http://pureenergysolar.com > 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. > > > 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. %^^% > > _______________________________________________ > 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 > > > > > > -- > ======================== > Brian Mehalic > NABCEP Certified Solar PV Installer™ R031508-59 > IREC ISPQ Certified Affiliated Instructor/PV US-0132 > PV Curriculum Developer and Instructor > Solar Energy International > Carbondale, CO 81623 > http://www.solarenergy.org > > _______________________________________________ > 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 >
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