Lemming's [RE-wrenches]

Thu Feb 6 09:28:00 PST 2003

Hi Graham,

You're O-so-right about being cautious in utilizing "cutting-edge"
technology. The problem is, and always has been, that without being willing
to stick your neck out, progress would never happen at all. I see this
situation as being a metaphor for the solar and wind energy as a whole, and
actually technology in general.
I have noticed that the majority of wrenches who have come from the ranks of
conventional electrical contracting tend to be the most conservative in
their willingness to be the guy on point.

There has been plenty of discussion on this list about the trend toward
standardization, accepted electrical methodology, safety issues and
less-than-prime-time equipment but, the fact remains; without risk and the
pioneering spirit technology grinds to a halt. In the late 70's and early
80's everything we installed was experimental in the extreme, except for
flooded batteries. Personally, I prefer that time because of the freedom and
latitude to innovate that was the "zeitgeist" of the period, over the
current normalization and standardization paradigm. Sure, things are way
more predictable and reliable now, but how do you think they got that way?

The big hope in this business has always been to be able to make a good
living at it while still having fun.
Are we having fun yet?

New and improved, fully attached flame shields up!

Cheers,

Matt T
----- Original Message -----
From: "Graham Owen" <graham at solarexpert.com>
To: <RE-wrenches at topica.com>
Sent: Thursday, February 06, 2003 8:49 AM
Subject: RE: Lemming's [RE-wrenches]

> Hi Matt,
>
> I now have full confidence selling and installing SB's as reliable
> devices.  I knew this product had a solid background in Germany and well
> as other European countries my concern was with how they would hold up
> under the extreme summertime heat in the San Fernando Valley.  I knew a
> lot of guy's that installed ST's and when summer arrived with
> temperatures over 103 degrees the problems began.  I still have concerns
> about fully loading SB's to the max and using the Sunny Breeze fan,
> which I think I recall being told, should last 2-3 years.  As a
> contractor taking advantage of emerging renewable incentive programs, I
> have to provide a full five-year warranty.  Undoubtedly there will be
> service calls in the future. A problem will occur if and when the
> subsidies have dropped below a level that provides enough incentive for
> new PV construction.  This will present a dilemma for solar contractors,
> how do we provide free service calls if there is no more income being
> generated by new PV system installations?  There are many reasons why I
> am trying to be as careful (slow and methodical) as possible so as not
> to fall into the sea as Bill suggested, rather I would rather be one of
> the slow lemmings, which stay around to reproduce in the future.
>
> Graham
>
>
>
> -----Original Message-----
> From: matthew tritt [mailto:solarone at charter.net]
> Sent: Wednesday, February 05, 2003 8:17 PM
> To: RE-wrenches at topica.com
> Subject: Re: C40's and SW's [RE-wrenches]
>
>
> Hi Graham,
>
> I can't see why you would consider your customers to be Guinea Pigs when
> installing SBs for them, considering the lengthy experience with the
> units in Germany and elsewhere. The actual award for The Biggest
> Experiment should go to either Advanced Energy or Xantrex. No? We all
> have installed plenty of those and replaced almost as many. I wonder
> what will happen when the repaired GC's start crapping out! Big fun for
> sure. I told one of my customers about the bankruptcy and I got the
> strangest look! :-)
>
> Matt T
> ----- Original Message -----
> From: "Graham Owen" <graham at solarexpert.com>
> To: <RE-wrenches at topica.com>
> Sent: Wednesday, February 05, 2003 2:02 PM
> Subject: RE: C40's and SW's [RE-wrenches]
>
>
> > Hi Bill,
> >
> > Thanks for the sound advice.  When I wrote my long-term business plan,
>
> > with a lot of lessons learned from the 1986 collapse of the solar
> > industry, I vowed to only install products with at least two years of
> > untroubled local performance.  This may sound crazy to some, but I
> > have only just recently started working with SB inverters.  I don't
> > like making my customers guinea pigs.
> >
> > Thanks again, from a slow lemming,
> >
> > Graham
> >
> >
> > -----Original Message-----
> > From: Bill Brooks [mailto:billb at endecon.com]
> > Sent: Wednesday, February 05, 2003 1:42 PM
> > To: RE-wrenches at topica.com
> > Subject: RE: C40's and SW's [RE-wrenches]
> >
> >
> > Jay,
> >
> > With all due respect to the Outback folks, for grid-tied systems I
> > would not be so quick to toss my C-40s for a Max Power controller,
> > whether MX-60 or SB50. The additional cost may or may not pay for
> > itself over time and the reliability is an unknown. I don't think
> > anyone has enough hard data to make that blanket assessment.
> >
> > Our industry has been so quick to run like lemmings to the sea every
> > time a new idea or product comes on the market. I always like to ask
> > the lemmings why they are running so fast, where they are going, and
> > for what reason. They seldom can provide me with good information to
> > join them.
> >
> > Bill.
> >
> >
> > -----Original Message-----
> > From: Jay Peltz, Peltz Power [mailto:jay at asis.com]
> > Sent: Tuesday, February 04, 2003 6:30 PM
> > To: RE-wrenches at topica.com
> > Subject: Re: C40's and SW's [RE-wrenches]
> >
> >
> > I think that any discussion of C-40's on large arrays, especially
> > intertie is a moot point.
> >
> > Most interties are pretty large and so the use of a MPPT controller is
>
> > very cost effective and is any easy swap out.  ( especially as the
> > MX-60 fits the same KO's)
> >
> >
> > In regards to the higher voltages equalling higher power, yes but I
> > have never seen any change in the output of the SW with the higher
> > input voltages.
> >
> > Peace,
> >
> > jay
> >
> > Peltz power
> >
> > ----- Original Message -----
> > From: "Jeffery Wolfe, Global Resource Options"
> > <jeff at globalresourceoptions.com>
> > To: <RE-wrenches at topica.com>
> > Sent: Tuesday, February 04, 2003 11:29 AM
> > Subject: RE: C40's and SW's [RE-wrenches]
> >
> >
> > > Bill,
> > >
> > > Although you're right that the C40 should never control, the point
> > > of the higher voltage settings is to make more power. We all know
> > > that the PV's will put out more power at higher voltages, so setting
>
> > > the inverter
> > higher,
> > > for float, is better. We also need to balance this with battery high
> > limits,
> > > and the fact that you need a pretty significant "dead band" in the
> > > control setpoints between the C40 and the Trace, due to inaccuracies
>
> > > in the
> > voltage
> > > meters in both units. (Trace told me 1.5 V, I'm typically using
> > > about 1.0 V).
> > >
> > > The 53.6VDC default on the inverters is also on the very low side of
>
> > > where we're floating batteries, even on-grid, today. We're moving
> > > hotter, more like 54.8 to 55.2. Batteries that float all year long
> > > tend to have
> > sulfation
> > > problems, and it seems that the hotter setpoints help reduce this.
> > > (Along with the little black boxes.) Couple this with the fact that
> > > on-grid
> > higher
> > > float voltages are going to produce more power, the case is made for
> > setting
> > > the floats about as high as the manufacturer's will let you. We do
> > > use
> > bulk
> > > mode, as it's good (IMHO) to bulk the batteries occasionally. So we
> > > set
> > the
> > > bulk up at about 58 VDC. This then pushes the bulks on the C40's up
> > > to
> >
> > > 59
> > to
> > > 59.5, in order to provide as much dead band as possible.
> > >
> > > We've got three years on our double C40 / SW system, as well as
> > > several others around the area. The low set points "work", but are
> > > not
> >
> > > the best
> > for
> > > power production (remember, we all complain about power production
> > > on PV systems), and are not necessarily the best for battery life.
> > >
> > > I do agree that the C40 float and bulk can be set the same, but it's
>
> > > more like setting the float to the same as a more typical bulk,
> > > rather
> >
> > > than the other way around.
> > >
> > > I also always use a Fluke to set up the C40 (and any other
> > > controller). I never trust the little dials or displays. They can be
>
> > > wrong (on any controller).
> > >
> > > Jeff
> > >
> > > -----Original Message-----
> > > From: Bill Brooks [mailto:billb at endecon.com]
> > > Sent: Tuesday, February 04, 2003 1:10 PM
> > > To: RE-wrenches at topica.com
> > > Subject: RE: C40's and SW's [RE-wrenches]
> > >
> > >
> > >
> > > Graham,
> > >
> > > I believe that bulk charging is meaningless in a grid-connected
> > application.
> > > Since the system is floated all the time, except during a power
> > > outage,
> > the
> > > focus is on the float settings. I would set the bulk timer on the
> > > inverter to 0:00 so it automatically goes to float. The default for
> > > the inverter is 53.6 Volts for float and I think that is fine for
> > > most
> >
> > > lead-acid
> > batteries.
> > > The key is making sure the C-40 is set at least one volt higher. It
> > > is
> > also
> > > critical that all controllers and inverters have temperature
> > > compensation probes installed and sensing basically the same
> > > temperature.
> > >
> > > Finally, check the C-40 while operating to make sure it is not
> > controlling.
> > > By testing the voltage drop across the C-40 positive battery and PV
> > > array inputs, you can tell whether it is controlling. The voltage
> > > should always
> > be
> > > below 0.75 Volts, otherwise it is controlling. It should only
> > > control in
> > an
> > > outage. Set the C-40 bulk at the same as the float, since the array
> > > should not be bulk charging the battery anyway. Bulk charging
> > > doesn't help a battery that stays at float all the time. It can
> > > actually hurt a VRLA battery by overcharging it if you allow it to
> > > bulk for more than a
> > half-hour
> > > or so. Hope that helps. Others may see it differently but I have
> > > over four years of grid-connected experience with my C-40s and SW.
> > >
> > > Bill.
> > >
> > >
> > > -----Original Message-----
> > > From: Graham Owen [mailto:graham at solarexpert.com]
> > > Sent: Monday, February 03, 2003 9:01 PM
> > > To: RE-wrenches at topica.com
> > > Subject: C40's and SW's [RE-wrenches]
> > >
> > >
> > > Dear Colleagues,
> > >
> > > I need some Wrench assistance with a PV service call, for the
> > > Xantrex Power Module system (or power panel for that matter), you
> > > have to set the C40 charge controllers and the SW inverter so that
> > > the inverter can sell PV power to the grid without the controllers
> > > restricting current into the inverter in the first place. I am
> > > trying to determine
> >
> > > which set of values works the best.
> > >
> > > Are these good figures?
> > >
> > > C40  bulk   56.0
> > >      float   55.0
> > >
> > > inverter bulk  54.0
> > >        float   53.2
> > >
> > > Thanks in advance!
> > >
> > > Graham
> > >
> > > P.S. Joel, I am working on finding your CPUC answers, I was working
> > > out of town today.
> > >
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