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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. It\u2019s 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>
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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> 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>
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<DIV>R. Walters</DIV>
<DIV><A href="mailto:ray@solarray.com">ray@solarray.com</A></DIV>
<DIV>Solar Engineer</DIV>
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<DIV> </DIV><BR class=Apple-interchange-newline></SPAN></DIV>
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<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>
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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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