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

Thu May 24 16:23:29 PDT 2007

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Dang it Roy, I wish these things were a little cheaper and a little 
easier to come by. I missed out on a huge raft of NiFe's years ago - by 
a few hours. They had gone off to the scrap yard because the owner (who 
had them for 10 years) couldn't wait another 4 hours for me to get 
there. So is life (sometimes).

Matt

Roy Butler, Four Winds RE wrote:

>
> Matt,
>
> This post will probably wind up in electron limbo...but here goes...
>
> I have a bunch of Edison NiFe cells...made between 1932 and 1940 that 
> Bob Ellison and I took off of a steam train in Virginia.
> Some had been in continuous for a lot of years on the train and now 20 
> of these form a 24 volt bank I use here in the shop.
>
> Others from this same group had been discharged, shorted with jumpers 
> and stored for about 20 years.
> These are working quite well....accepting a charge and load testing to 
> 70-75% of their rated capacity.
> As with the NiCads, the Edison manual says to change the electrolyte 
> if the capacities drop over the years.
>
> 75 years and counting.....I'm thoroughly impressed!
>
> Roy Butler
> NABCEP Certified Solar PV Installer®
> NYSERDA eligible PV & wind installer Four Winds Renewable Energy, LLC
> 8902 Route 46
> Arkport, NY 14807
> 607-324-9747
> www.four-winds-energy.com
>
> Although no trees were killed in the sending of this message, a large 
> number of electrons were terribly inconvenienced.
>
>
>
>
> Matt Tritt 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
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>   
>>>
>>>
>>>
>>>
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