How long has this system been operational? Jay Peltz power
> On Dec 16, 2014, at 6:27 PM, Corey Shalanski <cshalan...@joule-energy.com> > wrote: > > Wrenches, > > I visited a customer today whose grid-tied battery backup system suffered > some sort of catastrophic failure, and now I'm trying to play detective to > figure out what happened and whose equipment/design is to blame. > > Here is what I know so far: > - System is ac-coupled with a Sunny Boy 7000 (7.85kW array), Magnum MS4448PAE > (x2), 3 strings of 4 12v batts (705Ah total) > - Site visit was triggered by the Sunny Boy registering zero output via > online monitoring. > - SPST Solid state relay installed on Sunny Boy output, controlled via Magnum > router, serves as secondary overcharge protection to Magnum's frequency shift > feature. Technician who initially responded claims he measured 240v across > the relay's terminals - relay manufacturer claims this is "100% impossible". > We removed the relay from the circuit, and the Sunny Boy is again operational. > - On arrival I found the Magnum display showing a "Low Battery Charge" > message with the bank measuring ~4Vdc. The individual batteries were in > various states of charge, ranging from high of 6.3v to low of -2.6v. These > measurements were taken at rest, all battery cables disconnected, and yes > three of the batts were registering a negative voltage. > - Customer reports that he was not aware of any recent prolonged power > outages. > > The three potential suspects would seem to be: > - SS relay: The customer is convinced that this is the weak link in the > system and somehow triggered this failure. I am not so convinced but would be > interested to hear recommendations for properly testing its functionality. > - Magnum equipment: Since there is low-battery-cutout protection, why would > this feature not have activated and prevented the batteries from draining so > low? > - Batteries: I am not very familiar with modes of failure, but our > distributor suggested that an internal short could be a possibility - what > might have triggered this? > > Clearly I am fishing for potential leads here, so any suggestions are welcome. > > Thanks! > -- > Corey Shalanski > Joule Energy > New Orleans, LA > ᐧ > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org >
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