[RE-wrenches] Bad Cell

[Phil Undercuffler]

You definitely have a problem cell, but I'm not so sure about it being a
defect which should be covered under warranty -- not at 6 years.
 Manufacturing defects show up in the first year or so, not way down the
road.  Without knowing more about the charge and discharge history, it's
hard to know for sure, but I'd recommend chronic sulfation should be ruled
out before yanking cells. What are the charge setpoints for the bank, the
average net charge current, and average daily discharge in amphours?  How
often is the bank charged to full (I mean really full, not just "it was
sunny and the meter got into the 90s" full).  That the other cells only got
to 1.260 tells me the bank isn't really charged to full yet, even though you
think that you're doing an equalization.  Remember, charging at greater than
60 volts when the specific gravity is less than 1.265 is really just
unregulated charging, not equalizing.

Good luck with it,

Phil Undercuffler



On Sun, Jun 20, 2010 at 11:38 AM, Allan Sindelar <
allan at positiveenergysolar.com> wrote:

>  Yep, sure sounds like you have a bad cell. It may be covered under
> warranty. You can jumper around it, to temporarily take it out of the system
> while you secure a replacement. Reset the charge settings to 23/24 of what
> they'd be otherwise.
>
>  *Allan** Sindelar*
> Allan at positiveenergysolar.com
> NABCEP Certified Photovoltaic Installer
> EE98J Journeyman Electrician
> *Positive Energy, Inc.*
> 3201 Calle Marie
> Santa Fe, New Mexico 87507
> *505 424-1112*
> www.positiveenergysolar.com
>
> On 6/20/2010 11:24 AM, dan at foxfire-energy.com wrote:
>
> Sure sounds like you lost a cell... what's the resting voltage of that
> battery compared to the other three? (-1/6?) db
>
>
> Dan Brown
> Foxfire Energy Corp.
> Renewable Energy Systems
> (802)-483-2564
> www.Foxfire-Energy.com
> NABCEP #092907-44
>
>  -------- Original Message --------
> Subject: [RE-wrenches] Bad Cell
> From: "Mark Frye" <markf at berkeleysolar.com <//markf at berkeleysolar.com>>
> Date: Sun, June 20, 2010 1:12 pm
> To: <re-wrenches at lists.re-wrenches.org<//re-wrenches at lists.re-wrenches.org>
> >
>
> On a battery back with 4 - 12v HUP 1690 Ah wired for 48VDC, I went out the
> other day and "charged" up the bank and give it a fair amount more at an
> equalizing voltage.
> I checked the specific gravity pretty much right away with the batteries
> still warm and bubbling. All cells read about 1.260, except a single cell
> that appears to have an graivity of 1.000.
> Is this normal for a single cell in a bank to crap out completely while all
> the others remain in fairly good condition?
> The bank is 6 years old and has been equiped with a Watermaster system from
> day one.
> I can't believe that I have somehow washed out 3 gallons of electrolyte by
> overfilling or something.
>
> Mark Frye
> Berkeley Solar Electric Systems
> 303 Redbud Way
> Nevada City,  CA 95959
> (530) 401-8024
> *www.berkeleysolar.com* <http://www.berkeleysolar.com>
> ------------------------------
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