[Fwd: silent sell mode] [RE-wrenches]

Wed Jul 12 16:46:14 PDT 2000

FYI,

I am forwarding e-mail from Tony Boatwright at Trace regarding the fabled
"silent sell" mode:

Tony Boatwright wrote:

> Hello Todd,
>
> I will try to respond to your inquires in Ray's stead.
>
> You are correct Trace has looked at a scenario called "silent sell" which is
> similar in operation to the description you gave below. We think this will
> benefit most line-inter tie users, but as you have  been rightly told, the
> capacity of the EPROM's in the SW are full and decisions must be made to
> determine if some current features are to be deleted or to create or
> "revamp" a new SW.
>
> The 82% you see at 1kW is possible based on what inverter model and the
> overall system installation, but I have seen higher levels obtained at the
> 1kW power level from the SW.
>
> Personally, I have worked through different scenarios and we continue to
> "bounce off" different configurations as to what we will do to the next
> generation SW's, but the "silent sell" view is at the top of the list and I
> think it (or something very similar) will be provided on the next
> generations of SW's.
>
> As for when this may hit the streets,  I don't think anyone here at Trace
> would be accurate if they gave you a time. I would only say that it is a
> project we have put down on paper and have discussed many times.
>
> Tony Boatwright
> Technical Support Manager
> Xantrex Trace Engineering
> >
> >
> > -----Original Message-----
> > From: Todd Cory [SMTP:toddcory at jps.net]
> > Sent: Tuesday, July 11, 2000 3:43 PM
> > To:   rbarbee at traceengineering.com
> > Subject:      silent sell mode
> >
> > Hello Ray,
> >
> > I was given your name by someone on the "RE wrench list" as someone at
> > Trace to contact. I am frustrated with the very inefficient operational
> > options on the SW series of inverters in "sell" mode. About 5 years ago
> > I contacted someone there named "Gordon" regarding this situation. He
> > mentioned Trace Engineering would soon be out with what he called a
> > "silent sell" mode.
> >
> > Here's what I am after:
> >
> > The inverter would be in it's normal "sell" operational mode unless:
> > 1) there were no renewable energy sources to feed back into the grid and
> >
> > 2) the batteries did not need charging
> > IF the grid was still active it would continue to pass the power through
> > it's transfer switch and put itself into the silent mode...
> >
> > In this mode of operation, it would only turn itself back on if:
> > 1) the battery voltage went above a set point indicating power to "sell"
> > back into the grid or
> > 2) if the battery voltage dropped below a set point to activate the
> > battery charger or
> > 3) if the grid failed when it would pick up the loads that were going
> > through the transfer switch.
> >
> > This would eliminate the wasteful overhead of having the unit running
> > all night when there is no need for it to be doing so. Sometimes in the
> > winter when our daily solar gain is minimal, I would speculate that the
> > inverter is actually producing a net loss which is NOT good.
> >
> > As you know, PV power is quite expensive and I find it frustrating that
> > the "best" equipment on the market for grid intertie, results in an such
> > a high  operational overhead. In addition to this, the seemingly low
> > efficiency I see of approximately 82% while back feeding around 1 kW
> > really seems  unacceptable. Please don't misunderstand me, the Trace SW
> > series has revolutionized the inverter market, setting the standard for
> > most to follow. However I am trying to point out that there remains room
> > for improvement in the grid intertie mode.
> >
> > I have been told that you are not offering this mode of operation
> > because at present the grid interactive market is too small to bother
> > with. Also that the EPROM onboard the SW units is already full and that
> > adding more code would necessitate a whole revamp of the control
> > hardware.
> >
> > I am curious if you have ever considered adding the operational option I
> > suggest and if there is any possibility of it becoming a reality in the
> > not too distant future? I also wonder if it is true that currently there
> > is insufficient memory onboard to accommodate this. It seems it would
> > not be too difficult to expand the memory capabilities to accommodate
> > the efficiency gains this option would afford. As more grid tied systems
> > are requested it would be wonderful to not have to try to explain the
> > high energy overhead of the intertie equipment.
> >
> > Thank you in advance for the information and entertaining my expanded
> > grid intertie suggestions.
> >
> > Todd Cory
> > --
> > Todd Cory
> > KE6SXS
> > toddcory at jps.net
> > Bald Mountain Solar
> > P.O. Box 689
> > Mt. Shasta, Ca. 96067
> > (530) 926-1079

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