[RE-wrenches] Request for Enphase inverter comments

[R. Walters]

Hi Mark;

I appreciate your concern with replacing a faulty inverter:  
definitely sounds troublesome, about as much work as replacing a  
faulty module.
But consider this: An Enphase inverter failure will only diminish the  
total system performance by one panel, the rest of the modules will  
still be working.
With a large single inverter failure, you have more of an emergency  
call.
I actually find the redundancy of the Enphase appealing, but again I  
haven't tried one yet.

Ray Walters


>
> If we look ahead at the Enphase we see a very different situation.  
> Here we
> are still getting replacement of the inverter. Instead of a field  
> service
> fee for the installer, the customer gets a cost of energy refund?  
> But now,
> in order to service the inverter, we have to get on the roof,  
> disassemble
> the array, replace the inverter, re-assemble the array. And this  
> will may
> have to be done multiple many time over the life of the system.   
> The real
> cost to the installer/customer here is huge and not even nominally  
> close to
> the value of lost energy production.
>
> I agree with Bill, that in this case the nature of the warranty is  
> not the
> really significant issue here.  The issue is the cost to maintain and
> operate a system that falls to the owner after the manufacture and
> installers are long gone.
>
> I am disappointed by the warranty offering not so much for what it  
> is, but
> that it is offered as a substitute for reasonable representations  
> as to the
> projected life-cycle cost of ownership of systems based this product.
>
> I give my customers a 25 ROI projection for each of my systems.  I  
> include
> nominal array maintainence costs and inverter replacement costs  
> (parts and
> labor) at year 12.
> The question arises, what model for real maintenance costs over a  
> 25 year
> term should be included in estimates for an Enphase system.
>
> Our industry is mature enough that we should expect this kind of  
> information
> from all providers, old and new.
>
> Mark Frye
> Berkeley Solar Electric Systems
> 303 Redbud Way
> Nevada City,  CA 95959
> (530) 401-8024
> www.berkeleysolar.com
>
> -----Original Message-----
> From: re-wrenches-bounces at lists.re-wrenches.org
> [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of  
> Bill Brooks
> Sent: Friday, October 24, 2008 8:51 PM
> To: 'RE-wrenches'
> Subject: Re: [RE-wrenches] Request for Enphase inverter comments
>
> Mark,
>
> I'm surprised that you are disappointed and put so much stock in  
> warranties.
> Working with any new product and new company requires a go-slow  
> mentality at
> the start to establish a track record and field experience. A  
> warranty is
> only as valuable as the company behind the warranty. Enphase is a  
> promising
> new company, but installers do both Enphase and themselves a  
> disservice if
> they go whole hog after this technology and treat it like other  
> more-mature
> options. Installations should be close to the shop on roofs that  
> are easily
> accessible.
>
> Expecting a warranty beyond 10 years is excessive. Quite frankly,  
> warranties
> beyond 5 years don't make any sense to me (but the law is the law).  
> We will
> not fix long-term performance with warranties. Remember that a 25-year
> performance warranty on modules is really not what most people  
> think it is.
> It is a good failure warranty and a terrible performance warranty.  
> Long-term
> performance comes from quality equipment, quality design, quality
> installation, and good maintenance.
>
> Keep up the quality work.
>
> Bill.
>
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R. Walters
Solarray.com
NABCEP # 04170442	



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