Xantrex versus Sunny Boy [RE-wrenches]

Jeff Clearwater clrwater at earthlink.net
Thu Jul 31 17:21:56 PDT 2003


<x-flowed>
Matt,

Does LOL mean Lots of Lafferty? :)

It's okay we simply can't get enough.

Best

Jeff C.

>Jeff C wrote:
>
>>  you just put the SBs and disconnects under or at the end of your racks
>
>Jeff, do you mean like the SMA pictures of European installs?  (On their
>backs with a tilt)  Are you insinuating that you can't put a PV on its
>back and expect it to operate?  LOL
>
>Seriously, folks... A couple of "issues" are missing from this thread.
>
>1. Triple Orientation is a given factor, but at what slope(s)?  (Don't
>assume it's a relatively flat install!)  The steeper the slopes, the
>greater the difference in Power, Volts, Amps, Temperature, Etc. between
>them.  It all adds up!  Power tracking the "average" of the different
>slopes will yield a far greater (Estimated @ up to APPROXIMATELY 48%
>annual) kWH using the SB option vs the single PV.... Assuming
>Crystalline modules.  (This is not to be interpreted as the PV being 48%
>less efficient than the SB!!!!!!  Please don't go there! Even though
>John B & Kent S might want you to....).  That kind of production
>difference (If my VERY ROUGH 3-BEER calcs are even close) factors
>heavily into Customer satisfaction  (Read as: "Less headaches for me").
>I wouldn't use the comparison in ANY presentation to a Customer, by the
>way...Remember it is VERY ROUGH, based on the info I do have.  That # is
>a simple comparison of projected kWH of one scenario to the other on an
>annualized basis....The real objective is to develop the best overall
>system option(s) for the Customer.  Many factors play into "best"....
>Price, Performance, Reliability, Aesthetics, Warranty, "Feel Good",
>Patriotism, "Payback", "Marketability", Confidence, "What my
>Wife/Husband will think", Financing, Capitol Gains/Losses, Property
>Taxes, Etc.  There is also the "what they intuitively think" factor
>relating to future electricity rates and usage.
>
>2. Knowing (because I asked offlist) that the slope is 25 degrees, and
>that the Hilo, HI latitude is ~20 degrees N, leads me to a
>recommendation that the slopes not be combined on a single inverter.  At
>the very least, balancing the factors I know, I would separate the
>orientations to different inverters for this application.  Could be that
>is 3 - PV10's.... Could be that is 12 - SB's.  Further penciling is
>required to determine the "Best" option for the Customer.
>
>Crystal Ball: 12 SB's beats 3 PV10's......
>
>Two Palms and a Hammock to all!
>
>Matt Lafferty
>Universal Energies Institute
>mlafferty at universalenergies.com
>(916) 422-9772
>(916) 628-7694 Cell
>(916) 914-2247 Fax
>www.universalenergies.com
>
>
>-----Original Message-----
>From: Jeff Clearwater [mailto:clrwater at earthlink.net]
>Sent: Thursday, July 31, 2003 9:11 AM
>To: RE-wrenches at topica.com
>Subject: RE: SPAM: Xantrex versus Sunny Boy [RE-wrenches]
>
>
>Hey Bill,
>
>Gotta disagree on the space and efficiency issues you raise.  The 36
>KW system with 12 SBs we are installing fits in a 6 x 8 power shed
>only using up the walls and you still have the whole room.  A PV50208
>(and the transformer) for that system would have required a fork lift
>and lots more space - wouldn't even have fit in the door!  And with 1
>Square D HU361  per 2 inverters  - that's only 6 -  5" wide
>disconnects - hardly a space issue.
>
>And on commercial flat roof installs - especially retrofits - you
>just put the SBs and disconnects under or at the end of your racks
>and you don't need a whole dedicated power room.
>
>As for efficiency including the transformer, aren't you at 90% with
>the PV whereas SB is at 94% and with a better efficiency curve?
>
>respectfully,
>
>Jeff C.
>
>>I think there are several factors being overlooked in the responses.
>>COST is certainly one major one. I don't think SMA can come close to
>>competing with the PV series on cost. Efficiency I think is close to a
>  >wash between the two even with the higher nighttime losses of the
>>isolation transformer. Both machines use IGBTs and they are very
>>efficient at high power--they are not efficient at low power. SPACE is
>  >another problem. 30 kW of SunnyBoy inverters takes up tremendous space
>>with disconnects and all. I think the breakpoint between the SB and the
>
>>PV is between 10-20 kW.
>>
>>I really don't think the MPPT issues with the different orientations is
>
>>an issue. I do think the MPPT of the SB is slightly better than the PV
>>series in general, but I have not seen any good data to confirm that.
>>
>>Reliability--I think the PV series is every bit as reliable if not more
>
>>so than the SB.
>>
>>Both great inverters--the best inverters we have in our industry. The
>>PV series is better suited for this installation (just to be a
>>contrarian--in your heart you know I'm right--to quote Barry
>>Goldwater).
>>
>>Bill.
>>
>>-----Original Message-----
>>From: Marco [mailto:marco at pvthawaii.com]
>>Sent: Wednesday, July 30, 2003 2:59 PM
>>To: RE-wrenches at topica.com
>>Subject: SPAM: Xantrex versus Sunny Boy [RE-wrenches]
>>
>>
>>
>>I'm getting differing opinions on a design question that's leaving me
>>in a bit of a quandry.  I'm pursuing a 30 kW DC grid-tied system sale
>>to the local healthfood store here in Hilo, ~19 degrees north
>>lattitude.  There's 3-phase 120/208 service at the store, so I'd like
>>to use a single Xantrex PV30208 inverter (and isolation transformer). 
>>Since there's not enough roof space on the due south face for all 30
>>kW, the array would be split roughly equally among the southern,
>>eastern and western faces of the roof.  Each series  string of (12) 24V
>
>>modules would be on one plane, i.e., no series string would span two
>>roof faces.  Now, I know very well that splitting this system onto
>>three planes is not ideal when using a single inverter. However, I'd
>>much prefer to use one inverter rather than (12) 3-phase SB2500s.  Nor
>>do I want to use three 10-kW PV10208 inverters--one each per roof face.
>
>>So, my question to my esteemed PV wizards is, how poorly or
>>sub-optimally do you think such a system will perform?  Any of you out
>>there who have installed similar multi-plane, single-inverter systems?
>>
>>tanks,
>>aloha,
>>marco
>>
>>Marco Mangelsdorf
>>President
>>ProVision Technologies, Inc.
>>69 Railroad Avenue, Suite A-7
>>Hilo, Hawaii 96720 USA
>>(808) 969-3281, fax 934-7462
>>www.provisiontechnologies.com
>>
>>
>>
>>[Non-text portions of this message have been removed]
>>
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>
>
>--
>~~~~~~~~~~~~~
>Jeff Clearwater
>Village Power Design Associates
>Sustainable Energy & Water Solutions for Home & Village
>http://www.villagepower.com gosolar at villagepower.com
>
>877-SOLARVillage
>413-256-6777,  Fax 413-825-0372
>61 Baker Rd
>Shutesbury, MA 01072
>
>PO Box 115
>Boonville, CA 95415
>707-895-9015, Fax 707-897-0024
>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~`~
>
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-- 
~~~~~~~~~~~~~
Jeff Clearwater
Village Power Design Associates
Sustainable Energy & Water Solutions for Home & Village
http://www.villagepower.com
gosolar at villagepower.com

877-SOLARVillage
413-256-6777,  Fax 413-825-0372
61 Baker Rd
Shutesbury, MA 01072

PO Box 115
Boonville, CA 95415
707-895-9015, Fax 707-897-0024
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~`~

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