[RE-wrenches] Quantity of L-16 in a string

Thu Feb 16 12:16:57 PST 2012

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
jdeboever at trojanbattery.com<mailto:jdeboever at trojanbattery.com>
www.trojanbattery.com<http://www.trojanbattery.com/>

From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at 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 - dana at solarwork.com<mailto:dana at 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-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of john
Sent: Wednesday, February 15, 2012 9:18 PM
To: re-wrenches at 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 <william at millersolar.com>
To: RE-wrenches <re-wrenches at 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: william at millersolar.com<mailto:william at millersolar.com>

http://millersolar.com<http://millersolar.com/>

License No. C-10-773985

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