[RE-wrenches] Batteries in parrallel Failure

[Darryl Thayer]

Batteries in parallel, How to protect from catastrophic failure.
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)  


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.  


Ideas Please?  




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