inverter shoot-out at high noon [RE-wrenches]

Sun Mar 28 11:22:50 PST 2004

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Really good information Henry. The only comment I would like to make has
to do with the Suntie. From the contact I have had with the new (and the
old) models, they just plain make too much audible noise to mount on a
small dwelling. One very nice installation on a house in San Luis Obispo
has the inverter mounted at the meter location - outside the living
room, but the entire house "hums", even all the way across the house in
the bedrooms. Even the neighbors have complained about the noise!

Another person I met had actually replaced his Suntie with a SunnyBoy
for the same reason.

No matter how cool the performance may be, a product is only as good as
it's most negative feature. Is there a new and improved version, or have
I only seen obsolete models?

Matt T

-----Original Message-----
From: Michael Welch [mailto:michael.welch at homepower.com] 
Sent: Sunday, March 28, 2004 10:54 AM
To: RE-wrenches at topica.com
Subject: RE: RE: inverter shoot-out at high noon [RE-wrenches]

===========================================================
**** Bounces like rubber! Shatters like ceramic! ****
Discover Crazy Aaron's Thinking Putty in grown up 
handfuls. It's the creativity unleashing, mood enhancing 
desk toy!
http://click.topica.com/caab5n2bz8QcsbadqCja/ Crazy Aaron Enterprises
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Henry asked me to post the below on his behalf.

Bill Brooks wrote at 06:27 PM 03/26/2004:

>Chris and Joel,
>
>I can't remember what modules Mr. Cutler had on his house, but a 5% 
>increase is a little hard to believe even with the worst mismatch in 
>modules. I'm sure some manufacturers are worse than others, but I would

>be careful about throwing around those kinds of numbers without a 
>little better substantiation.

Gentleman, 

It was nice to see my new work being mentioned By Chris F about my panel
matching in my newest system. 

In my latest system , I purchased (36) , new photowatt 155 Si modules
for 2.47 watt. These were "seconds" but who cares , a watt is a watt.
The -155s ranged for a low of 146 watt to a high of 179 watts. I current
matched the strings , in most cases within 1 watt , since I'm using a
nominal 48 volt array. The 5% number is if the exact same panels were to
be used with a long series HV string ,like for a sunnyboy , I'd lose the
gain panel matching has.

The Photowatts came with individual curve trace from the solar-simulator
at the factory. Btw my  almost 2X the cost Kyocera didn't. The panels
have tolerances of -3/+5% for the TIGHT tolerance ones , what you put on
your customers arrays , who knows , how does one tell ?

The entire issue of focusing on Peak or Rebate efficiency numbers as the
metric for good performing solar systems is very misleading. I realize I
am NOT the first person to come across current matching of panels , and
in dollars , the solar panels are the ones getting the free ride so to
speak. The Bottom line IMHO is what a system cost to how much power it
generates.

So if I'm not the first , can someone please point me to where and
installer finds this out ? does the new solar installer certification
even talk about panel matching ?. What about the DIY crowd ? . I feel
the need to get the word out , in a similar way to the drive I had for
the HP91 article , that high voltage strings have a  cost , and that is
your totally at the mercy of the panel manufactures in how your shinny
red box will perform (John B , by the way where is my royalty check for
the sunny breeze name :).. At least with 48 volt strings
(Suntie/Outback/M5) you have options to over come the panel variances.

FYI , the Suntie GP/UPG on my Kyocera arrays were with 1-2% when I
finished my work over a year ago even though the inverters have a 3-4%
efficiency difference. On this photowatt array , the Suntie would be
ahead by 3%, and if John wants to send another box , I'll run the test
to prove it

I think using solar panels to verify inverters is the wrong approach ,
there are to many variables.  I agree that a solar simulator (pc
controlled power supply) is the most likely short term solution , but
who is going to pay for this 50K piece of specialized hardware and who
will verify the tester ?

I think the use of low voltage strings will make a come back , why ?
because bottom line is the owner/installer can control the factors to
maximize the system's performance. Once you own the panel , they are
what they are ... With 48 volts , you can use bigger wire and match the
panels to offset any raw efficiency differences (were talking 4% from
worse to best on all the CA listed inverters) 

There should be more focus on system performance , and before you blow
this off and think , well My panels are premium , they will be closely
matched , think about this , Every wonder why there are 15 different CPU
speeds for sale ..... all the same chip ?? , its all about Si
Manufacturing process  , if Intel can't make it 100% the same , what
chances do the panels guy have

As Chris mentioned , Under Contract , I redesign the Suntie and yes I
believe it is an outstanding product now ... I have invested a year of
my life in making it perform flawlessly , reliably and in temperature
extremes. Xantrex , Due to the HP article as seen the sales basically
die of and it really is a shame since the product I reviewed has little
in common with the GP/UPG

<http://www.solar-guppy.com/forum>www.solar-guppy.com/forum if you want
to continue this discussion as I don't have posting ability to this
list.

Henry Cutler 

Michael Welch

------------------------
"All power rests on hierarchy: an army is nothing but a well-organized
lynch mob."
			Edward Abbey

Michael Welch, michael.welch at homepower.com
     Home Power magazine
     www.homepower.com
     To reach me: 707-822-7884
     To reach Home Power: 800-707-6585

===========================================================
**** Bounces like rubber! Shatters like ceramic! ****
Discover Crazy Aaron's Thinking Putty in grown up 
handfuls. It's the creativity unleashing, mood enhancing 
desk toy!
http://click.topica.com/caab4CEbz8QcsbadqCjf/ Crazy Aaron Enterprises
===========================================================

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===========================================================
**** Bounces like rubber! Shatters like ceramic! ****
Discover Crazy Aaron's Thinking Putty in grown up 
handfuls. It's the creativity unleashing, mood enhancing 
desk toy!
http://click.topica.com/caab4CEbz8Qcsbz9JC9f/ Crazy Aaron Enterprises
===========================================================

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