Battery Experience/Suggestions for Grid Tie? [RE-wrenches]

[Bob Ellison]

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Yes, nicad's are a hell of a battery bank BUT they are among the most
toxic things on the earth, and vert expensive, 10-20 X the cost of a
GOOD lead acid battery bank!
Probably will not get to topica but worth the try.
Bob

On 5/24/07, Matt Tritt <solarone at charter.net> wrote:
>
>
> It's hard to bead NiCads for longevity and robustness. I know someone
> who has lived off-grid on a farm back East with a pair of small wind
> turbines (Dunlite and a Swiss machine) for many years with a NiCad bank
> from the 50's. This has to be some kind of record! They told me that
> "all you have to do is replace the electrolyte every 10 or 20 years, and
> you're good to go. Jeeze Louize!
>
> Matt T
>
> Todd Cory, Mt. Shasta Energy Services wrote:
>
> >That is another advantage of lead calcium wet cells. They use next to no
> >water. In the 20 years the bank I inherited were at our hydro plant,
> >they had water added only twice. Equalizing is not recommended more than
> >ever few years (if ever) either. They are robust and not easily damaged.
> >They last a very long time and are specifically designed for float
> >conditions. The only downside is the cost.
> >
> >The price to replace those lead calcium wet cells down at the dam was
> >around $10K for 12 kW (20 X 6 volts X 100 a/h). By comparison 20 kW of
> >L-16's were at the time about $1.3K. And that is for about twice the
> >a/h's. The life span is about 1/3 but still, even considering that the
> >price differential is about 10X!!
> >
> >If you have a customer that tends to not pay close attention to the
> >batteries in their backup system, AND price was not an issue... these
> >are the cells I would choose.
> >
> >Todd
> >
> >
> >
> >Doug Pratt wrote:
> >
> >
> >>Hey Travis. Grid tie and wet-cell batteries are not usually a happy
> >>combo.
> >>Two primary problems. 1. Customers forget to service (water) them. I've
> >>never visited a grid-tied wet-cell battery pack without finding exposed
> >>plates. It's just too easy to forget them. 2. All the common deep-cycle
> >>wet-cell batteries on the market (T-105's, L-16's, Rolls-Surrette, and
> >>Hawker) expect to be used and cycled regularly. Their chemistry isn't
> >>built
> >>for long, long periods of float charging. Think of them like the muscles
> >>of
> >>your body. They need modest amounts of regular exercise to stay healthy.
> >>Don't go to wet cells with grid-tie unless they're specially constructed
> >>for
> >>emergency backup service, and you do some kind of automatic (or very
> >>easy
> >>semi-automatic) watering system.
> >>
> >>Sealed batteries are usually expected to go into emergency backup
> >>service,
> >>their chemistry is tweaked a bit so they're happier doing long stretches
> >>of
> >>float service without becoming hopeless weaklings. AGM sealed types are
> >>easier to build (and therefore usually cheaper...Concorde's excepted,
> >>especially the past couple years!), but they're fluid starved so have
> >>little
> >>tolerance for even the least overcharging. Gel sealed types are trickier
> >>to
> >>build, but start out with greater fluid reserves, so they're a bit more
> >>tolerant of the occasional overcharge. Gels will usually last 10% to 15%
> >>longer than AGMs.
> >>
> >>I've been selling the MK Gels (made by Deka I believe) for over a
> >>decade.
> >>Service life is roughly 5 to 10 years. It depends a lot on the
> >>customer's
> >>use and charging patterns. Set your charging voltages no higher than
> >>2.35
> >>volts per cell with sealed batteries. NO equalizing!
> >>
> >>Oh God! I've ventured into BATTERIES! A world with no black or white but
> >>plenty of gray areas. Let the flames begin... (got my nomex shorts on).
> >>
> >>Cheers,
> >>Doug Pratt
> >>DC Power Systems
> >>
> >>
> >>-----Original Message-----
> >>From: Travis Creswell [mailto:tcreswell at ozarkenergyservices.com]
> >>Sent: Wednesday, May 23, 2007 7:23 AM
> >>
> >>Hello All,
> >>
> >>We've got several grid tie customers with aging or dead Concorde AGM
> >>battery
> >>banks.  They feel that they got pretty poor calendar (4-6 years) life
> >>from
> >>these batteries and the customers are not that excited about going back
> >>with
> >>another ~5 year battery bank.  We did about 20 systems in 1999 with
> >>Concordes and only one of them is still alive.  All in all we weren't
> >>that
> >>impressed with Concordes.  How have MK AGMS been doing for folks?  We've
> >>got
> >>a few really small sets out there
> >>
> >>Both of these customers have budgets and I think would tolerate paying
> >>more
> >>for batteries in exchange for getting a longed life battery bank.  Both
> >>banks are in the basement but with some construction we could construct
> >>a
> >>venting system so flooded batteries are not out of the question.  But
> >>I'm
> >>not sure either of these customers would properly maintain flooded
> >>batteries.
> >>
> >>So what batteries should I be looking at?  I'm pretty sure we need to
> >>just
> >>skip right past T-105 and L-16.  What about the HUP or similar in float
> >>service?  One customer has several multi day power outages annually.
> >>The
> >>other rarely looses power for more then a few hours a year.
> >>
> >>I'll look forward to suggestions.
> >>
> >>Regards,
> >>
> >>Travis Creswell
> >>
> >>Ozark Energy Services
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >
> >
> >- - -
> >--^----------------------------------------------------------------
> >
> >
> >
> >
>
> [Non-text portions of this message have been removed]
>
>
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