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<DIV>Not surprised at all about the phone company guy. It was a phone
company guy who read me the riot act that no one in their right minds would ever
parallel battery banks the way PV off-grid systems did and got me to set up my
system with separate strings connected independently to buss bars. The
battery engineer I talked to years ago at Dynasty not only said the same thing
but also said keeping strings separate meant individual string distance from the
bars became irrelevant (given correctly sized wire for each string’s parallel
connectors). I had a system with 12 100 amphour strings of paired 12v
Dynasty AGMs which was rock solid until the day I sold the house.
The last time I checked the system before the sale no single battery varied from
any other in the system by more than 1/10 volt and the majority were still
holding identical voltages.</DIV>
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<DIV style="font-color: black"><B>From:</B> <A title=dan@foxfire-energy.com
href="mailto:dan@foxfire-energy.com">dan@foxfire-energy.com</A> </DIV>
<DIV><B>Sent:</B> Wednesday, June 01, 2011 4:14 PM</DIV>
<DIV><B>To:</B> <A title=re-wrenches@lists.re-wrenches.org
href="mailto:re-wrenches@lists.re-wrenches.org">RE-wrenches</A> </DIV>
<DIV><B>Subject:</B> Re: [RE-wrenches] 24 volt Battery Bank
comparison</DIV></DIV></DIV>
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<DIV>Good thread. Thanks. </DIV>
<DIV>In my experience, it all boils down to the customer. I've seen one temp.
set up with like 12 strings (for a concert). but they were recharged and sold
individually within a few weeks.. I've also seen a single string (Teledyne
aircraft batteries) fail in less than a year.. they were in a brand new airplane
tug that was never charged -- ever. (the guy said "I dunno, it just stopped
working").</DIV>
<DIV> </DIV>
<DIV>I have one customer who (last I knew) was running 6 strings of mixed aged
L-16s going on 8 years. Thing is, he's a retired phone company dude (Who's
missing half of his right hand from using one of those pocket pal screwdriver
thingys on a key chain in a hot DC rack.. like he'd done hundreds of times
before.. but that's another tale). But I do like his set up.. he has each string
set up with it's own fused Disco and Trimetric.. Gives him random control over
each string. And yes, he keeps a very detailed log, and you can bet that when he
takes a battery out of service, it's done.<BR></DIV>
<DIV> </DIV>
<DIV>Me? for an average bullet proof off grid system, I shoot for a max of two
strings for 24V systems (for the redundancy), and manually reconfigure them
every few years. for 48V systems, I shoot for <SPAN>one string of two Volt
cells<SPAN id=GD__CURSOR></SPAN></SPAN>.. thinking that if I loose a cell I can
still operate a 46V system until I get a replacement.</DIV>
<DIV> </DIV>
<DIV>And Yes, as we all know, there are folks out there that really shouldn't be
allowed to operate a popsicle stick. </DIV>
<DIV> </DIV>
<DIV>db<BR></DIV>
<DIV> </DIV>
<DIV><BR>Dan Brown<BR>Foxfire Energy Corp.<BR>Renewable Energy
Systems<BR>(802)-483-2564<BR><A
href="http://www.Foxfire-Energy.com">www.Foxfire-Energy.com</A><BR>NABCEP
#092907-44</DIV>
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<DIV id=wmQuoteWrapper>-------- Original Message --------<BR>Subject: Re:
[RE-wrenches] 24 volt Battery Bank comparison<BR>From: Michael Welch <<A
href="mailto:michael.welch@re-wrenches.org">michael.welch@re-wrenches.org</A>><BR>Date:
Wed, June 01, 2011 1:43 pm<BR>To: RE-wrenches <<A
href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</A>><BR><BR>Every
now and then I see reference on this list to the need for thermal detection.
Here is an interesting, inexpensive piece of equipment that could be used for
finding hot (loose or corroded) connections, hot batteries, hot PV cells in
modules, and even poorly insulated spots, its original intended
purpose:<BR><BR><A
href="http://www.blackanddecker.com/power-tools/TLD100.aspx">http://www.blackanddecker.com/power-tools/TLD100.aspx</A><BR><BR>I
have one and used it for finding uninsulated spaces, but cannot attest to its
durability or suitability for the other uses mentioned above.<BR><BR><BR>boB
Gudgel wrote at 01:00 AM 6/1/2011:<BR><BR>>This might be a good reason for
an installer to have one of those FLIR (or similar) thermal imager cameras. Â
They're a bit on the expensive side, but could<BR>>really be helpful for so
many things.  Even just to know if you have left a nut loose (under load of
course)<BR>><BR>>boB<BR><BR><BR>_______________________________________________<BR>List
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