[RE-wrenches] Battery capacity testers
North Texas Renewable Energy Inc
ntrei at 1scom.net
Mon Oct 4 06:36:17 PDT 2010
Todd
I've heard the same arguement, as well as its inverse. The battery choice was the decision of the system owner. I know they are more sensitive to charge/discharge abuse but I see the full charge rate last week at 52.xx V, just like day 1and I trust the Trimetric and the Sunny Islands. We're taking down the entire system to upgrade & install a 400A transfer switch so the batteries will have time to stabilize for the VOC check & cleaning.
I guess a more accurate question would be is it good enough to properly check cell VOC and not bother with the discharge capacity check? A compromise could be cap check 12V blocks of cells instead of all 24 separately. Or is the capacity checker a waste of money.
Jim
----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org]On Behalf Of toddcory at finestplanet.com
Sent: Monday, October 04, 2010 2:23 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] Battery capacity testers
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" <ntrei at 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
ntrei at 1scom.net
817.917.0527
www.ntrei.com
Sent from Finest Planet WebMail.
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