[RE-wrenches] weak voltage

[mac Lewis]

Hmmm,

This had factory installed bussing.  I will pull it off and clean it up.
 Thanks.  I suppose that something like this be invisible to an Amp hr
meter.

On Sun, Oct 14, 2012 at 11:01 PM, William Miller <william at millersolar.com>wrote:

> 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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-- 



Mac Lewis

*

"Yo solo sé que no sé nada." -Sócrates
*
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