[RE-wrenches] Enphase v. string inverter

Keith Cronin electrichi01 at yahoo.com
Sun Oct 10 11:04:54 PDT 2010


Perhaps some day in the not too distant future, we will switch from tax credits 
(like in Hawaii) to performance based incentives and this topic will be resolved 
from empirical evidence vs unsubstantiated claims.
Then the educated public can see a side by side comparison.
This would have to have some independent verification and a side by side 
comparison of string vs individual inverters, or we are just guessing.

Next week in LA at SPI, there is bound to be more enphase types of products 
hitting the market. Eventually, I see it all going that way- having them built 
in. Sure there are lots of debates, like this past months article in solar pro 
magazine, but if they came off the assembly line AC ready, it will truly be 
another appliance that needs to be plugged in.

String inverters for all of us have kept the riddle alive by not always 
providing the granular information for us to know the effectiveness of the solar 
panels and the varying site conditions they are required to work in.

Aloha

Keith



________________________________
From: Darryl Thayer <daryl_solar at yahoo.com>
To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
Sent: Sun, October 10, 2010 2:52:02 AM
Subject: Re: [RE-wrenches] Enphase v. string inverter


I have seen the top performing contractor in my area sell behind a chiminy and 
under a tree, claiming 10% more using Enphase than unshaded.    

Darryl

--- On Sun, 10/10/10, Jamie Johnson <jjohnson at spefl.com> wrote:


>From: Jamie Johnson <jjohnson at spefl.com>
>Subject: Re: [RE-wrenches] Enphase v. string inverter
>To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
>Date: Sunday, October 10, 2010, 7:38 AM
>
>
>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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