Battery less Inverters [RE-wrenches]

[Steve Bell]

Hi Travis,

    I just got off the phone with John, our dealer (he is competent) ; here
is what he says.
He has two ST-based systems operating; one is a single ST2500 with 1,000
watts of Arco modules, the other is system has two ST-2500s and about 2,200
watts of UniSolar modules per ST.
Both systems seem to be acting the same way. Multiple times during the day
the ST will power up to about 650 to 700 watts and then cycle off. Many
times the LCD display goes dim or shuts off and the  Total Daily Watt-Hour
reading on the LCD re-zeros when it cycles down. The units do come back on
after a short while. This happens many times during the day.
Although he does not have exact monitored data, it seemed that the power
output of the ST is well below expected. On a sunny day with 2,200 watts of
UniSolar the ST was indicating less than 800 watt-hours of output.
The cooling fan comes on whenever the ST output climbs above about 200
watts.

John talked to Dean at Trace about the problems he is having. Dean says that
the ST may cycle off and on several times in the morning and then
occasionally (two-three times) during the day. John reports that the cycling
is much more frequent throughout the day.
Dean says that the ST may be too aggressive in its power tracking and they
(Trace) may need to adjust it's aggressiveness. The fan operating anytime
the ST output is over 200 watts is supposed to be some code or regulatory
requirement. (It seems like it should only operate when the ST is warm.)

Because the ST sometimes losses the daily watt-hour total on the LCD when it
cycles, it sounds like the unit is totally cycling down during it's many
daily cyclings. (The LCD also shuts off and clears the WHr total every
night.) It sounds like Trace may need to supply a replacement chip to fix
this cycling problem. It also sounds like some independent measurements of
ST output v.s. array input may be well advised.

In fairness to Trace, this is their Ver.1 of the ST. Hopefully they will fix
the problems quickly. Remember the Ver.1 SW-series had problems too.

I hope this explaination makes sense. Thanks for all the feed-back so far.
Any other experiences with the ST are welcome.

Steve Bell
SunWize Technologies
Stelle
sebpv at stelle.net

----- Original Message -----
From: "Travis Creswell, Ozark Solar" <ozsolar at ipa.net>
To: <RE-wrenches at topica.com>
Sent: Wednesday, February 07, 2001 01:22 AM
Subject: Re: Battery less Inverters [RE-wrenches]


> Steve,
>
> Could you elaborate a little more?  Did they trip out when the array
reached
> ~600 watts then stayed out until they were manually reset then promptly
> tripped again at anything above ~600 watts... or did things get "funny" at
> ~600 watts but were OK everywhere else above and below that?
>
> Thanks
> Travis


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