I'd vote to listen to the manufacturer. It's in their best interest to provide a reliable solution. Good call.
On May 31, 2011, at 8:23 PM, "Wayne Irwin" <wa...@pureenergysolar.com> wrote: > I think the verdict is 12 - Rolls 2-YS-31 2430 AH @ 20 HR (one string) and > one dry spare in storage is the best case scenario! > > 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. > > > > > > Date: Tue, 31 May 2011 18:16:56 -0600 > From: al...@positiveenergysolar.com > To: re-wrenches@lists.re-wrenches.org > Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison > > Tom, > 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?"). > > 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. > > 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: > 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! > > as I just put that exact size of IBE 2V cells in my own home. Here's hoping I > get another 18 years and 10 months out of them. > Allan > > Allan Sindelar > al...@positiveenergysolar.com > NABCEP Certified Photovoltaic Installer > NABCEP Certified Technical Sales Professional > New Mexico EE98J Journeyman Electrician > Positive Energy, Inc. > 3201 Calle Marie > Santa Fe, New Mexico 87507 > 505 424-1112 > www.positiveenergysolar.com > > On 5/31/2011 5:36 PM, Tom Elliot wrote: > 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 > > _______________________________________________ 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 > _______________________________________________ > 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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