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<DIV>What? No royalties? Damn...(but thanks for the props)
Sorry I misunderstood what you meant.</DIV>
<DIV> </DIV>
<DIV>My installs of buss bars back in the day had cable pairs of the same length
but different pairs could be of different lengths with the consideration being
bank construction. Id use slightly oversized cables to minimize
resistance differences. Since the cables from each string only carried
current from that string it also made for easier installation. In these
days of grid-tie Im seeing less and less discussion of batteries, good to see
another one happening even if it was prompted by a failure, though I guess
thats how we learn.</DIV>
<DIV> </DIV>
<DIV>Tom</DIV>
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<DIV style="font-color: black"><B>From:</B> <A title=ray@solarray.com
href="mailto:ray@solarray.com">R Ray Walters</A> </DIV>
<DIV><B>Sent:</B> Wednesday, April 20, 2011 8:16 AM</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] Batteries in parrallel
Failure</DIV></DIV></DIV>
<DIV> </DIV></DIV>
<DIV
style="FONT-STYLE: normal; DISPLAY: inline; FONT-FAMILY: 'Calibri'; COLOR: #000000; FONT-SIZE: small; FONT-WEIGHT: normal; TEXT-DECORATION: none">Tom;
<DIV> </DIV>
<DIV>That's exactly what Daryl and I were suggesting: all strings paralleled to
a central combiner box with breakers on each series string.</DIV>
<DIV>The only thing I left out was that each cable set should be the same length
( which Daryl was already suggesting).</DIV>
<DIV>You need to reread what we were talking about. We got this idea from
you many years ago, so the record is not broken;</DIV>
<DIV>its been pirated, reposted for Free download on all sorts of unsavory
sites, and you aren't getting a royalty check....</DIV>
<DIV>Imitation is the sincerest form of flattery, and this list listens to and
appreciates you.</DIV>
<DIV> </DIV>
<DIV>Thanks,</DIV>
<DIV>
<DIV>
<DIV> </DIV>
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<DIV>R. Walters</DIV>
<DIV><A href="mailto:ray@solarray.com">ray@solarray.com</A></DIV>
<DIV>Solar Engineer</DIV>
<DIV> </DIV>
<DIV> </DIV><BR class=Apple-interchange-newline></SPAN></DIV>
<DIV> </DIV>
<DIV>
<DIV>On Apr 19, 2011, at 10:16 PM, Tom Elliot wrote:</DIV><BR
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<DIV>The broken record will now repeat himself yet again. Bussbars are
the way to go, not across battery terminals but individual strings connected
to a central positive and negative buss from which the inverter connection
then runs. This allows fusing of each individual connection and also
allows for smaller positive cables and no need to have identical length
parallel cables since each string is independently connected. Its what
telecom installations use. The Telecom guys who showed me how to do it
literally laughed when told about paralleling across battery terminals.
They then told me they considered it profoundly stupid and dangerous and since
I had just avoided a meltdown myself by catching a bad cell before complete
failure I got the message pretty quick.</DIV>
<DIV> </DIV>
<DIV>Really guys, this is amazingly simple and yes, it may mean a bit more
cabling and another component but from a safety standpoint those
considerations are pretty minor and cheap insurance against disaster.</DIV>
<DIV> </DIV>
<DIV>Tom</DIV>
<DIV> </DIV>
<DIV> </DIV>
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<DIV style="BACKGROUND: #f5f5f5">
<DIV style="font-color: black"><B>From:</B> <A title=ray@solarray.com
href="mailto:ray@solarray.com">R Ray Walters</A> </DIV>
<DIV><B>Sent:</B> Tuesday, April 19, 2011 6:01 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] Batteries in parrallel
Failure</DIV></DIV></DIV>
<DIV> </DIV></DIV>
<DIV
style="FONT-STYLE: normal; DISPLAY: inline; FONT-FAMILY: 'Calibri'; COLOR: #000000; FONT-SIZE: small; FONT-WEIGHT: normal; TEXT-DECORATION: none">I
like the fused parallel idea; could save the system, and would make battery
troubleshooting nice.
<DIV>I would suggest #6 jumpers with 50 to 60 amp breakers, so the
system could be operated on just a few strings if needed.</DIV>
<DIV>
<DIV> </DIV>
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<DIV>R. Walters</DIV>
<DIV><A href="mailto:ray@solarray.com">ray@solarray.com</A></DIV>
<DIV>Solar Engineer</DIV>
<DIV> </DIV>
<DIV> </DIV><BR class=Apple-interchange-newline></SPAN></DIV>
<DIV> </DIV>
<DIV>
<DIV>On Apr 19, 2011, at 8:29 PM, Darryl Thayer wrote:</DIV><BR
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<DIV
style="MARGIN: 0px; FONT-FAMILY: 'times new roman', 'new york', times, serif; FONT-SIZE: 12pt">Batteries
in parallel, How to protect from catastrophic failure.</DIV>
<DIV
style="MARGIN: 0px; FONT-FAMILY: 'times new roman', 'new york', times, serif; FONT-SIZE: 12pt">I
just got contacted to commission a solar system off grid not of my
design. Eight battery strings in parallel, AGM batteries, 24
volts @ 120 AH each string (two 12 volt in series) New system, new
batteries, Silent POwer Inverter. Two kW DC array. generator to
charge through Silent power. (present installer is not sure how to do
final set up and testing) </DIV>
<DIV
style="MARGIN: 0px; FONT-FAMILY: 'times new roman', 'new york', times, serif; FONT-SIZE: 12pt"> </DIV>
<DIV
style="MARGIN: 0px; FONT-FAMILY: 'times new roman', 'new york', times, serif; FONT-SIZE: 12pt">I
am most concerned about 8 batteries in parallel, (especially since last week
a set of AGM burned up having 5 in parallel Owner had no way to break the
paralleling of the batteries, she could only stop the chargeing)
What I am proposing for your review is requireing the installtion of
two combiner boxes Midnight solar with a breaker in each battery string,
using about 3' of #10 to connect each battery string to the combiner
box. This way if a battery failed and the paralled strings were to
"dump" into the failed battery it would trip the breaker. I was
thinking of using a 30 amp breaker in each string. The main breaker is set
at 240 amps. </DIV>
<DIV
style="MARGIN: 0px; FONT-FAMILY: 'times new roman', 'new york', times, serif; FONT-SIZE: 12pt"> </DIV>
<DIV
style="MARGIN: 0px; FONT-FAMILY: 'times new roman', 'new york', times, serif; FONT-SIZE: 12pt">Ideas
Please? <SPAN class=Apple-converted-space> </SPAN><BR></DIV></DIV>
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