I know many on this list disagree, but this sounds SO typical for sealed batteries. It is why I never use em... never! If they are 5 years old, you are probably at the limit of their life. Replace em with flooded lead calciums and your customers (and you) will be happy for 20+ years.
my .o2 Todd On Sunday, October 3, 2010 9:28pm, "North Texas Renewable Energy Inc" <nt...@1scom.net> said: I have a customer with a set of 24 Concord PVX-6480s that have twice failed during grid outages during the night. No large loads are on the critical load panel and, since it's at night when they drop to 50% dod, I'm not sure what's up with them. I plan on cleaning and retightning all the cable connections first to eliminate that possibility then checking VOC of each cell. Eventually we'll install a 25 kW genset but my first task is to find out the state of the batterys. The system turns five next spring so I don't think they are near an early death. The BOS is 2 Sunny Island 4248s with upgraded chipsets and the charger is set to spec though that may need to be bumped up. The only culprit I suspect is the high summer temperatures in this unconditioned equipment room. Finally it may be time to invest in a capacity tester. What brand is popular among those Wrenches with lots of experience in diagnosing a batterys health? The Concord DC5000 only comes in 12 & 24 V models and these are 2V cells. Thanks as always Jim Duncan North Texas Renewable Energy 486 W.N. Woody Road Azle Texas 76020 NABCEP Certified Solar PV Installer No.31310-57 TECL 27398 [mailto:nt...@1scom.net] nt...@1scom.net 817.917.0527 [http://www.ntrei.com/] www.ntrei.com Sent from Finest Planet WebMail.
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