Mac:
We had a similar problem with a large bank of IBE 2 volt cells. The
batteries had to be removed the same day they were installed and then
reinstalled the next day. They sat outside for one night. The flags
acquired an invisible but insidious corrosion that caused problems getting
and keeping a charge. Now we insist on cleaning each flag and eyelet no
more than 10 minutes prior to contact.
William Miller
At 09:41 PM 10/14/2012, you wrote:
Hi wrenches,
About 2 months ago, we installed an off-grid Sunny Island System. Here
are the specs:
8.82 kW PV
SunnyBoy 8000
2 x Sunny Island 5048 Inverters
2490 Ahr SolarOne HUP batteries at 48V
30 kW Cummins Propane Generator
We are having an issue that I am having a hard time figuring out. We are
getting sagging battery voltage, and can't seem to keep the battery
voltage and specific gravity where we want it. In addition, I have
equalized these batteries 4 times this past month, and the specific
gravity gets to about 1.25-1.26 maximum. I have slowly eased up the
boost, absorb and equalize voltage setpoints, to try to get the battery a
better charge, but it doesn't seem to help. The Sunny Islands don't seem
to have any issue getting these batteries up to the equalization voltage,
or any of the other voltage set points. I have checked for loose
connections, all look good here.
The SOC monitor on the Sunny Island master, calculates that we are staying
between 70-95% SOC on a daily basis, and yet the battery voltage has
dropped below readable level a few times(I believe this is below 41V). I
equalized at 62 V for 4 hours and had the same result of nonimpressive
sepecific gravity and saggy voltage under small load. After we leave from
equalizing the batteries, things seem to be OK for a while and then we
start having issues again. We are tripping a 250A battery breaker, and
getting low voltage errors on the SI, yet SOC looks good.
Right now I have the set points programmed per SolarOnes advice as:
Boost Voltage= 2.46 V/cell
Full Charge Voltage = 2.46V/cell
Equalize Voltage = 2.54V/cell
Thanks in advance for any ideas that you may have.
--
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