Mysterious Surrette Behavior [RE-wrenches]

Phil Undercuffler p.undercuffler at conergy.us
Wed May 24 10:30:43 PDT 2006


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I have some new information to pass on, based on long discussions with Jamie
Surrette.  There is something nice about calling a company and speaking to
people in charge who really know their products.

There are three things that are of concern, that I want to try to address. 

One:  a client got a bad cell.  

I now know there are a lot of ways a mistake can happen in building a
battery, and not all of them can be caught before the battery is shipped.
It sucks, you try to keep it from happening, but mistakes can happen.  It's
how you deal with it that matters, and we're working with Surrette and Ray
to get the issue resolved in the best way possible.

Two:  Required charge rates, and fears of compromising battery life

There is definitely a lot of confusion over this issue, and I've heard from
many battery manufacturers that we in the solar industry tend to be heavy on
the lead, light on the charge (first heard that from Jim Drizos of Trojan,
years ago at an SEI training).  Yes, I do believe we could benefit from
increasing charge rate and decreasing days of autonomy--backed up with a
bottled energy charging source.  But Jamie pointed out that we should use
the 20 hour capacity rate for this calculation.  Based on this, he has no
issue with the design of Ray's system based on battery capacity, days of
autonomy and charge rate.

Three:  Changing back to GC batteries will resolve the issue.

The acceptance rate for a 660AH bank made up of golf cart batteries vs a
single string of larger cells of the same capacity (no matter the
manufacturer) will be essentially identical.  Jamie would argue that the
larger batteries would be more efficient to charge than the bank consisting
of multiple paralleled strings.  I think that Ray was right to focus on
buying the best cycle life for the buck.

Let me know what you folks think.

Please note new phone extensions
 
---------------------------------------------------------
Phil Undercuffler
Technical Service Manager, ext. 0741
Conergy, Inc.
1730 Camino Carlos Rey Suite 103
Santa Fe NM  87507 USA
Tel 505-473-3800 ext 0741
Fax 505-473-2134
www.conergy.us
---------------------------------------------------------
 

-----Original Message-----
From: Ray Walters [mailto:walters at taosnet.com] 
Sent: Friday, May 19, 2006 9:54 PM
To: RE-wrenches at topica.com
Subject: Re: Mysterious Surrette Behavior [RE-wrenches]


Hi All;

Well I'm ready for a better battery thats for sure.
After reading everyones' post about Rolls needing a C10 to C5 rate of 
charge, I'm starting to feel sick to my stomach. I just talked a bunch 
of folks into buying  Rolls 5000s because they  had the best  "claimed"  
cycle life of  any battery around. My relatively low income customers 
laid  out very hard earned cash  to get  the best  possible battery, and 
now  they  may have made  a  big mistake. Sorry, but I don't think many 
of my customers have the ability to charge at a C10 rate. I dutifully 
sized their battery bank for 5 to 6 days of storage based on their load 
profiles. That means about a C20 rate, Man am I a loser....
Now , I'm seeing Roll's warranty in action. They shipped us a brand new 
cell that  was 0 volts.  Its hard to catch an under performing cell, but 
0 volts right out the door? Thats seriously bad QC, and I and my 
customer are paying for it: not Rolls and not Conergy. If this is their 
warranty right out of the box, what are these profiteers going to offer 
in 5 or 7 years? ("You didn't charge at a C5 rate every week?!  Hah!  No 
battery for You!")
I get to haul batteries back and forth for 3 extra trips, spend about a 
day total, trouble shooting, doing temporary battery first aid to get 
the system up, drive several hours round trip to get the new cell, 
siphon the acid out of  the dead cell into the new cell..... are we 
having fun yet? making any money? losing lots of  money? And lets add 
$200 shipping to expedite the replacement a  couple of weeks?
Well, I sold a battery with a 10 year warranty, and I stand by what I 
sell. (even if they don't)  I'll fix everyone of these. I guess that's 
why I'm a "little" company and they're a "gweat big company". ( I knew I 
should have signed up for that Cheney Business management class when I 
had a chance)
Prove me wrong, please, but the small installer gets screwed every time.
Well, my meager little operation sells several tons of Rolls a year and 
thats stopping right  now.
 I sell Trojan too, and they drop a new battery at my door, free, no 
questions asked. I've had 2 bad batteries in 5 years.
I guess its back to golf cart batteries, until somebody does something.

Ray Walters
ray at solarray.com
NABCEP, RPCV, BSME


Ezra Auerbach, DragonSun Consulting wrote:

>Hi,
>
>I'd like to add some general comments about big batteries and off grid
>systems. I've had occasions to discuss the matter of oversized batteries
(or
>undersized charging systems) with a few battery manufacturers. They have
>been consistent in telling me that the ability to apply significant amounts
>of minimum current to batteries is key to successfully charging them. As a
>general rule of thumb they specify a minimum of the C10 rate for initial
>(max bulk amps) charge rate and C5 if you can perhaps deliver it. In my
>various jobs over the last twenty years I've also had the opportunity to
see
>countless battery systems which were oversized for the available charging
>system, a very high percentage underperformed with respect to longevity
>expectations. I think the battery manufacturers are correct in demanding
>high capacity charging systems for their large batteries - especially those
>offering long warranties. 
>
>I've lived with large capacity batteries for years (the same set for the
>last fourteen) and I can attest that the only time I really get them fully
>charged from renewable is on those bright sunny days when the wind is
>howling as well - I can get pretty close to the C10 rate of my batteries in
>those conditions and they respond very nicely to the extra charge current.
>I've even been known to start the generator early in one of these perfect
>weather charge cycles to add an extra 80 amps or so to the initial rate.
>
>Bottom line for me is that battery charging is a lot like cooking. Bring
the
>electrolyte up to temperature with current and the magic transformation of
>water into acid occurs. Without sufficient current the electrolyte never
>gets sufficiently warm for a full charge process to occur and the batteries
>remain essentially "under cooked". I often compare battery charging to
>cooking a pot of pasta. You can put the pasta in a pot of cold water and
>leave it on the stove on low all day. At the end of the day you'll have
>tepid mush but it won't be cooked pasta. You need to apply sufficient heat
>to boil the water to cook the darn stuff, much like you have to apply
>sufficient current to charge the batteries.
>
>Best regards,
>
>Ezra
>
>  
>Ezra Auerbach
>DragonSun Consulting 
>Morewater Road 
>Lasqueti Island, B.C. V0R 2J0
>
>Tel 250.333.8650
>Email: ezra at lincsat.com
>

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