[RE-wrenches] weak voltage

Chris Mason cometenergysystems at gmail.com
Mon Oct 15 09:02:38 PDT 2012


Anything more than a few millivolts.

On 10/15/12, mac Lewis <maclewis1 at gmail.com> wrote:
> 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
> *
>


-- 
Chris Mason
President, Comet Systems Ltd
www.cometenergysystems.com
Cell: 264.235.5670
Skype: netconcepts



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