Wrenches, Dana, Battery banks can be configured with parallel strings, each string consisting of the number of units to meet the 12V, 24V or 48V battery bank voltage required by the design. The recommended maximum number of strings in parallel is 4. The lesser number of string in parallel will reduce the chance of dealing with cells unbalances, which inevitably occur over time, for the reasons you mentioned. I tend to limit the number of strings in parallel to 1 to 3 max whenever possible and especially in large battery banks. When push comes to shore, for very large Ah capacity applications it is recommended to have separate battery banks, each with their own independent charger, then parallel the battery banks and use blocking diodes.
John John F. DeBoever Global Technical Director - Renewable Energy Trojan Battery Company 12380 Clark Street Santa Fe Springs, CA 90670 Tel: +1-562-236-3000 Ext. 3139 Cell: +1-845-514-7600 - NY office time zone: USA EST (GMT-5) Skype: john.f.deboever Fax: +1-562-236-3239 jdeboe...@trojanbattery.com<mailto:jdeboe...@trojanbattery.com> www.trojanbattery.com<http://www.trojanbattery.com/> From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Dana Sent: Thursday, February 16, 2012 11:30 AM To: 'RE-wrenches' Subject: [RE-wrenches] Quantity of L-16 in a string Question to the battery wizzs' here and this may have some impact on the current thread.- I was told long ago by a Trojan battery rep. in 1990? that we should not extend beyond [12] L-16s in a bank due to too many connections and to many cells to achieve a really go balance on the cell to cell charge. I have seen this to be a reality over the years though I have no concrete evidence other than observation. The more L-16s in a bank the more imbalance or probability of imbalance due to the greater of cells and interconnects, points of connection, number of strings. At [12] L-16s I have seen the longest life at 8-9 years and any # of batteries beyond it drops off to the 5-7 year range. This is all, off grid observations as I have not seen any L-16 wet lead acid in grid tie applications. Manufacturers could you chime in and wrenches what is your experience? Thanks Dana Orzel Great Solar Works, Inc E - d...@solarwork.com<mailto:d...@solarwork.com> V - 970.626.5253 F - 970.626.4140 C - 970.209.4076 web - www.solarwork.com<http://www.solarwork.com> "Responsible Technologies for Responsible People since 1988" From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of john Sent: Wednesday, February 15, 2012 9:18 PM To: re-wrenches@lists.re-wrenches.org Subject: Re: [RE-wrenches] wrenches] Interstate L-16 vs Trojan L-16REB William, Back to the original question you posed. I have had good luck with Interstate L-16 batteries (so far). My first ones were installed in 2005 so I am just at the 7 year mark. I just looked some today and they are now failing at 7 years... one string of 4 real strong and the other 3 strings showing a weak battery in each. This system has been heavily abused with deep cycling due to generator problems and undersized PV array (and large loads). This was the system installed in a shed to power construction of a "modest" house that turned into a 3 story 5000 sf house and 3000 sf barn with 1200 watts of PV. I added another 1600 watts and now will be adding more along with new batteries. I have had lots of problems with the Trojan L16 HC's. Virtually all that I sold (may 5 or 6 systems) had premature failures. (1 to 3 years). I have seen comparable results with the Interstate L16 and the standard Trojan L16, but the interstates were considerably less expensive. I also have an Interstate supplier one block from my shop so convenience is part of the plus. I have had a few with leaking cell tops but was able to get instant replacements at no charge. On the question of grid tie, I had a set of 24 Trojan L16's last 12 years with one cycle per month performed by the owner. Off grid, however, around 7 years seems to be the norm. John -----Original Message----- From: William Miller <will...@millersolar.com> To: RE-wrenches <re-wrenches@lists.re-wrenches.org> Sent: Tue, Feb 14, 2012 3:45 pm Subject: [RE-wrenches] Interstate L-16 vs Trojan L-16REB Colleagues: Do any of you have experience with Interstate L-16 batteries? Are they a good value? Thanks in advance, William Miller Miller Solar Voice :805-438-5600 email: will...@millersolar.com<mailto:will...@millersolar.com> http://millersolar.com<http://millersolar.com/> License No. C-10-773985 _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org<mailto: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<http://www.re-wrenches.org/etiquette.htm> Check out participant bios: www.members.re-wrenches.org<http://www.members.re-wrenches.org/> This e-mail message and any attachments that accompany it may contain information that is confidential, privileged, or protected from disclosure. It is intended solely for the use of the individual(s) to whom it was intended to be addressed. 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