[RE-wrenches] intermittent battery problem; The Last Word

[Larry Crutcher, Starlight Solar Power Systems]

Ron, 
 
From what Daryl said below and the fact that your customer has about 15 amps of PV charge, you should deduct that the batteries have MOSTLY been deficit charged their entire life.  Here's what I told you on Oct 22 in my lengthy explanation about what the problem is and why it happened: "Undersized RE charging systems, or perhaps oversized batteries, is the culprit that contributes to this all too frequent phenomenon of chronic undercharging." 

You said that the customer has been compensating for an undersized system by running a generator. They can not know this because there is no monitor. The batteries now have a sulfation problem, perhaps unrecoverable, that could have been prevented if the owner had a battery capacity monitor. This is not pleasant news, I know. I have to explain this bad news to people MANY times each week. This is a huge issue globally. And such waste of money, time and resources just bugs me!

Larry Crutcher
Barer of Bad News
Starlight Solar Power Systems

On Nov 17, 2011, at 5:17 AM, penobscotsolar at midmaine.com wrote:

> Ron,
>   I'm going to reiterate what Jeff says here. It is similar to what I had
> said in my email. The charge rate must REGULARLY be C10 on the KS 
> (5000 series) batteries. This means, on KS 25's, a routine bulk
> charging rate of 135 amps. I find that on these types of hybrid
> systems, while the batteries might occasionally (sunny day, generator
> running, etc.) that kind of charging, they do not regularly see C10. I
> think if you gave Jamie Surrette a call he would give you the same
> possible assessment.
>   I do think the problem is oversulfation, but none of this solves your
> problem, I know. We have been installing KS series batteries since they
> came out and this necessity of regular C10 charging has been an
> integral  part of design for me for many years.
> 
> Best,
> Daryl
> 
> 
> 
> 
>> Ron,
>> 
>> 
>> 
>> This reply a little late since I have been off line a few days.  I
>> mentioned
>> in a similar thread last year that I had an off grid home client I
>> designed
>> and installed in Idaho back in 1998 that had a Kohler 8.5 kw generator, a
>> Trace 4024 inverter, two separate solar arrays and Outback charge
>> controllers, and 16 Trojan "L-16" batteries.  This system worked
>> flawlessly
>> for 7 years and only required the generator a few hours per month, then it
>> was time to change the batteries.  I replaced the Trojans with the same
>> size
>> battery made by Surrette and everything went to crap.  They had to run the
>> generator hours and hours to get them past an 80% charge and we had lots
>> of
>> problems with overloading the generator even though we did not make any
>> program changes and used the same generator.  The generator was replaced 2
>> years later but this system  never worked like it did before the battery
>> replacement.
>> 
>> 
>> 
>> When researching all this at that time I had talked with Surrette, Trojan,
>> and anyone else that might help and this is what I found out.  Of course
>> there are just my opinions based on these conversations, but it is my
>> understanding that Surrette is a much longer life battery with much less
>> water loss when comparing apples and apples, and I was told this was due
>> to
>> a different lead composition that Surrette uses than any other battery
>> manufacturer.  However, this difference requires a much longer
>> absorption/taper off charge process or you will never get it past 80%
>> charged.  This of course is almost impossible to achieve with a generator
>> or
>> undersized solar array, and you really need a grid connection to fully
>> charge these things.  No doubt these would be great in some standby grid
>> connected system but I no longer use them in off grid.  This was also at a
>> time when battery manufacturers were just discovering solar so maybe
>> battery
>> designs have changed.  Again, I think Surrette is a good company and makes
>> a
>> great battery, but just not sure you can fully recharge them with a
>> mid-sized generator.
>> 
>> 
>> 
>> I also do not like using parallel battery layouts as its hard to keep one
>> string from pulling down the other strings when there is a low performance
>> cell so you might do a cell by cell check.
>> 
>> 
>> 
>> Good Luck,
>> 
>> 
>> 
>> Jeff Yago
>> 
>> DTI Solar Inc.