ST versus Sunny boy [RE-wrenches]

Tue Aug 14 11:02:25 PDT 2001

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
_____________________________________________________________
Compatibility:
Word processor: WP7
Spreadsheet: Quatro Pro 7
CAD: Microstation 95, DXF, Visio 4.1T
_____________________________________________________________
"I stand by all the misstatements that I've made." Dan Quayle
__________________________________________________________________

- - - -
To send a message: RE-wrenches at topica.com

Archive of previous messages: http://www.topica.com/lists/RE-wrenches/

List rules & etiquette: http://www.mrsharkey.com/wrenches/etiquete.htm

Check out participant bios: www.mrsharkey.com/wrenches/index.html

Hosted by Home Power magazine

Moderator: michael.welch at homepower.com

- - - -
To send a message: RE-wrenches at topica.com

Archive of previous messages: http://www.topica.com/lists/RE-wrenches/

List rules & etiquette: http://www.mrsharkey.com/wrenches/etiquete.htm

Check out participant bios: www.mrsharkey.com/wrenches/index.html

Hosted by Home Power magazine

Moderator: michael.welch at homepower.com

==^================================================================
EASY UNSUBSCRIBE click here: http://topica.com/u/?bz8Qcs.bz9JC9
Or send an email To: RE-wrenches-unsubscribe at topica.com
This email was sent to: michael.welch at homepower.com

T O P I C A -- Register now to manage your mail!
http://www.topica.com/partner/tag02/register
==^================================================================