ST versus Sunny boy [RE-wrenches]

[Solar Technologies]

Another difference, however, is that the ST integrates a lightning arrestor;
my understanding is that the SB does not.

Roger DeNault
Solar Technologies

----- Original Message -----
From: <jberdner at sma-america.com>
To: <RE-wrenches at topica.com>
Sent: Tuesday, August 14, 2001 11:02 AM
Subject: RE: ST versus Sunny boy [RE-wrenches]


> William:
>
> Thank you for the feedback on the Sunny Boy.
> I would like to add two minor points of clarification.
> The SB also includes a GFDI fuse in every unit which eliminates the need
> for the GFDI breaker.
> The SB can be ordered with an integral display for local metering.
> Optional remote metering is available as you noted but is not the only
> metering option.
>
> Thank you again for your feedback.
>
> If you have any questions or I can be of any further assistance please
> do not hesitate to contact me.
>
> Best regards,
>
> John Berdner
>
> SMA-America, Inc.
> 20830 Red Dog Road
> Grass Valley, CA  95945
> Tel: 530.273.4895
> Fax: 530.274.7271
>
> -----Original Message-----
> From: William Miller [mailto:wrmiller at slonet.org]
> Sent: Monday, August 13, 2001 9:59 PM
> To: RE-wrenches at topica.com
> Subject: ST versus Sunny boy [RE-wrenches]
>
>
> Pals:
>
> Earlier I had written about some ST inverters that I thought might be
> providing low output.  It was asked that I provide more information on
> array, location, etc.  I investigated more thoroughly, measuring
> insolation, input current and voltage versus output current and voltage.
> During this process I gained access to the Sunny Boy 2500 watt
> inverters.
> I had a chance to perform a "side-by-side" comparison today--at least as
> close as side to side as one can.  I had the Sunny Boy installed and was
> able to switch over to the ST in about 40 minutes.  Here are the
> results:
>
> Array: 24 Siemens SR100 panels on two fixed, top of pole racks.
> Azimuth: Approx. true south
> Tilt: Approx. 16 degrees
> Temperature: Approx. 70 degree F
> Output Amp measurements: Averaged over 5 minutes with a Fluke 87 on one
> pole of 2 pole output breaker.
> Input amp measurements: Averaged over 5 minutes with a Fluke 87 on input
> DC
> lead (after combiner for ST)
> Array and AC voltage measurements: Beckman DVM
>
> Results:
>
> SB2500:
> 8/13/01 1:10 pm
> 7.00 avg @ 242 v ac (1, 694 watts)
> Insolation: 45 w/m2
>
> ST2500:
> 8/13/01 1:53 pm
> 6.31 @ 245 v ac (1, 545 watts)
> Insolation: 45 w/m2
>
> As you can see, the SB is about 10% better.
>
> I would note these other differences:
>
> The SB is quieter (no fan)
> The SB is string wired (smaller wire size, more flexibility where to
> locate).
> The ST has input and output and GFI breakers built in.
> The ST has metering built in.
> The SB offers optional remote metering and free monitoring and control
> software.
> ST clients are complaining about the ST shutting down periodically
> throughout the day, even after installing the latest chip upgrade.  One
> client found that after the chip upgrade, his system stopped shutting
> down,
> but the output dropped by about 10%.
>
> Any suggestions on testing procedures and any questions are appreciated.
>
>
> William Miller
>
> PS: I also checked efficiency of both inverters, comparing input watts
> against output watts.  They both range about 90%.  I can only surmise
> that
> the higher output on the SB is because it has a better MPPT circuit
> (loads
> the panels better).
>
>
> WM
>
>
>
> __________________________________________________________________
> William Miller
> SLO Communications: Communications and Power Systems Consulting
> PO Box 50, Santa Margarita, CA 93453
> Voice :805-438-5600 Fax: 805-438-4607 VMail: 805-546-4875
> email: wrmiller at slonet.org
> License No. C-10-773985
> _____________________________________________________________
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> _____________________________________________________________
> "I stand by all the misstatements that I've made." Dan Quayle
> __________________________________________________________________
>
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