[RE-wrenches] Enphase v. string inverter

Nick Soleil nicksoleilsolar at yahoo.com
Sun Oct 10 21:50:52 PDT 2010


    The main advantage of Enphase is the module level monitoring.  However, the 
increased output due to partial shading can be significant.  I was at a 6 year 
old PV site this week, and a tree had grown up near the base of the roof.  
Branches were casting a few minor shadows on the array, but was wiping out 75% 
of the production.  I can assure you, those 9 modules would have been producing 
'50+% greater output'
Nick Soleil
Project Manager
Advanced Alternative Energy Solutions, LLC
PO Box 657
Petaluma, CA 94953
Cell:   707-321-2937
Office: 707-789-9537
Fax:    707-769-9037




________________________________
From: Jamie Johnson <jjohnson at spefl.com>
To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
Sent: Sun, October 10, 2010 5:38:55 AM
Subject: Re: [RE-wrenches] Enphase v. string inverter


Marco,

The last I heard the NREL was testing enphase vs. a string inverter, they were 
also suppose to test enphase vs. A competitors module level mpp tracking.  Not 
sure if that performance test is complete yet.  

I have seen 1 independent unshaded test ( potentially biased ) which IIRC showed 
enphase ~1% less than a string inverter, this seems to match the inverters CEC 
rating.

What we see around here is an over estimate of kWh production by the selling 
contractor using enphase, sometimes by 50+% greater than unshaded kWh estimates.

Performance guarantees with monetary compensation back to the customer if 
estimates are not met can be a good thing and improve the industry IMHO.


Jamie Johnson
General Manager
SOLAR POWER ELECTRIC TM
NABCEP Certified Solar PV Installer #031310-118
(941) 380 - 0098
www.SPEFL.com
Commercial & Residential
FL State Certified # EC13001765

Sent from my iPhone


On Oct 9, 2010, at 7:07 PM, "Marco Mangelsdorf" <marco at pvthawaii.com> wrote:


Does anyone know of any reports out there from a neutral, 3rd party which 
compares an Enphase array with an array using a string inverter with both arrays 
on the same unshaded surface?
> 
>Some Enphase peddlers here are saying that the energy harvest from an Enphase 
>system is going to be better since they supposedly come on sooner and stay on 
>later in the day.
> 
>One guy is actually saying that the Enphase inverters come on before the sun 
>comes over the horizon.   Maybe from the same family that claimed that a-Si 
>modules produced power from the moonlight.
> 
>Thanks,
>marco
> 
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