olar Boost / C40 test [RE-wrenches]

[Bill Brooks]

Allan,

Why would you expect to see 35 volts under any sunlight conditions (except
below zero ambient temperatures)? You are quoting Standard Test Condition
numbers that should only be used as a starting condition to then convert to
real conditions.

Again, MPPT controllers are good for off-grid systems. The jury is still out
on whether they provide much benefit to on-grid systems. It will probably
depend very heavily on climate-specific issues. In California, with our
rainy winters and sunny summers, this makes MPPT controllers on
grid-connected systems produce the same or less power than a system without
an MPPT controller. Remember, the controller can take around 5% of the power
just to operate. Our industry needs these controllers, but we have to be
clear on when and how to use them. Hopefully RV will get their ETL listing
soon so we can use them in inspected systems.

Bill.

> -----Original Message-----
> From: Allan Sindelar, Positive Energy, Inc.
> [mailto:allan at positiveenergysolar.com]
> Sent: Friday, May 04, 2001 2:56 PM
> To: RE-wrenches at topica.com
> Subject: Re: olar Boost / C40 test [RE-wrenches]
>
>
> Blair,
>     A PV input voltage of 28.5 is low enough to suggest that one
> or more of
> these may apply:
> * An extremely hot day and module temperature
> * Excessive input voltage drop
> * MPPT adjustment on the SB50 not set optimally.
> I would expect to see an input voltage of around 35 volts before
> temperature
> deration. Any ideas?
> Allan at Pos Energy
>
> ----- Original Message -----
> From: "blair Tump may" <tump at midcoast.com>
> > Site; N44*   W 069*    temp amb; 92.2* panel top temp;117* back of panel
> > 124.2* array ang;44* facing;185* M Elv;170'
> >   System SW 4024 * 375 surrette batts.15 585 panels & 1 590 panel wired
> 24vt DC
> >
> > C40'    Battery voltage;25.46  panel voltage 26.32 DC amps in
> 39.5-40  AC
> > amps to grid 7.62  Brand WT Mtr  930 Avg
> >
> > Solar Boost 50; Batt.Vt.25.46 Panel Vt.28.5 DC Amps in
> 40.9-41.2  AC Amps
> > into grid 8.1 Brand WT Mtr; 970 Avg
>
>
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