[RE-wrenches] weak voltage

[mac Lewis]

How much voltage drop indicates a problem?

On Mon, Oct 15, 2012 at 8:13 AM, Chris Mason
<cometenergysystems at gmail.com>wrote:

> You should see a voltage drop across the connections if they are faulty.
>
>
> On Mon, Oct 15, 2012 at 8:54 AM, mac Lewis <maclewis1 at gmail.com> wrote:
>
>> 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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>
>
> --
> Chris Mason
> President, Comet Systems Ltd
> www.cometenergysystems.com
> Cell: 264.235.5670
> Skype: netconcepts
>
>
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-- 



Mac Lewis

*

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