Mysterious Surrette Behavior [RE-wrenches]

Thu May 25 15:20:32 PDT 2006

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Hi Phil & All;

So why would engineers at Surrette tell other wrenches we need a C5
rate? Is it just old school battery guys that don't understand the
special needs of solar? (I suppose the PC term for us would be "charge
rate challenged") When a company posts cycle life info, it should
include some info on the test procedures (ie. reccomended charge rates, 
charge voltages, etc.) I've made a pretty compelling argument for Rolls 
vs Golf cart batteries or L16s on my website. I based my conclusions on 
their cycle life data, cost, and actual experience. I don't want to turn 
out to be a liar. So the bottom line is this: does max. charge rate 
affect cycle life or not?

GCs vs Rolls:
I agree with Surrette that a single string would be more efficient. I
also know that lower charge rates are more efficient. (heavy gassing and
heating are clear symptoms that not all the PV power is being converted
to stored energy) But efficiency is not everything, and if lower charge
rates translate to lower cycle life, I need to factor that in to my
designs. Also, Why print a 100 hr discharge rate (about 4 days) which
seems to be the most appropriate for designing 5 to 6 days of storage,
if we should be using  the 20 hr rate? I always wondered how Rolls' 100
hr rate was so much better than other batteries. (Rolls' 100 hr rate is
around 40% more than their 20 hr rate, while other batteries increase
only by around 10%)

As for warranty and shipping, I deal with problem products all the time;
I've been in the solar business for a while. My beef is that most other
manufacturers I deal with, pay shipping to my shop. I've considered
doing a critique of various Manus' customer service: "The Good, The Bad,
and The Ugly". Many of the manufacturers will go beyond the letter of
their warranty to take care of a problem; especially when that problem
is right out of the box. As soon as they start reading me the fine
print, I quit wanting to promote their product:
end of story.

Ray Walters

Phil Undercuffler wrote:

>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 
>  
>

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