[RE-wrenches] Warranty Claim Based On Enphase Monitoring Data

[Phil Undercuffler]

First, I'd suggest swapping the inverter under the suspect module with it's
neighboring module's inverter.  See if the reduced output follows the
module, or the inverter.  If it follows the module, then I'd have a frank
talk with the module manufacturer, backed with the data you've gathered, to
see how they'll respond before yanking it out and shipping it back.  As you
note, it may be within spec, due to the tolerance of measurement error.
 Worst case, you've got instant vision as when the performance degrades
further to the point of clear warrantable failure.


Phil
-----------
"When we learn how to store electricity, we will cease being apes ourselves;
until then we are tailless orangutans. You see, we should utilize natural
forces and thus get all of our power. Sunshine is a form of energy, and the
winds and the tides are manifestations of energy.  Do we use them? Oh, no!
We burn up wood and coal, as renters burn up the front fence for fuel. We
live like squatters, not as if we owned the property.

There must surely come a time when heat and power will be stored in
unlimited quantities in every community, all gathered by natural forces."
-- Thomas Edison --



On Thu, Jun 9, 2011 at 6:32 AM, Mark Frye <markf at berkeleysolar.com> wrote:

>  Folks,
>
> Has anyone used Enphase monitoring data to get warranty replacement on new
> modules with sub par yield?
>
> I have several interesting questions stemming from access to Enphase module
> level monitoring data.
>
> Looking at data from a larger site (80 modules) with no shading issues,
> instant power production indicates a high degree of uniformity in panel
> power (Sharp NU-U240F1 and D380) easily within 1%.
>
> So what can we now say about the precision and accuracy of this monitoring
> data? It seems the old school thinking for string inverters was all the
> monitors were 5% off and reporting 5% more power than actual.
>
> Based on the data that I am looking at, it seems the microinverter meters
> must be fairly precise and possibly fairly accurate as well. Uniformity of
> module performance must also be fairly high.
>
> In any case, this data clearly shows a single module that is not performing
> as well as it's cohorts. For power levels above 50% of STC, it averages 9%
> less power than all other modules in the system. So off to Sharp for a
> warranty replacement? Yes, but, what if I am 5% low on the report from my
> inverter meter and 5% lower on my power from this one module? What if the
> module gets back to Sharp and they say it is within spec, now the costs are
> all mine?
>
> Interestingly enough, access to this monitoring data is making more work
> for me as an installer. With a string inverter, I would monitor power
> production readings monthly and be happy so long as yields were higher than
> what I projected when I designed and bid the job. Pretty much fire and
> forget.
>
> Now I am spending time on evaluating this data and doing the work to change
> out the module under warranty and so forth. I am going to end up putting in
> quite a few hours into this for what: to recapture 10% of 1/80 of total
> system yield….0.0013%.
>
> I am not complaining, just musing over this interesting evolution.
>
> Mark Frye
> Berkeley Solar Electric Systems
> 303 Redbud Way
> Nevada City,  CA 95959
> (530) 401-8024
> *www.berkeleysolar.com* <http://www.berkeleysolar.com>
>
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