Weatherman said:
It seems like Enphase is very inconsistent in their policy regarding m190 replacements.
I've gotten a reasonably good response, but only after it's obvious the micro is dead. Just degraded, even 20-30% reduction in power production doesn't cut it. For my array the m190 has to be dead before Enphase takes action. But, once they do, it has always been a very consistent response: one week to get the shipping notification and another week for delivery. Installation is paid for. The latest replacement is in transit without any delay in the normal routine, so I don't think they are running out of them.
there was a noticeable deteriorating trend that corresponded to one particular M215. Over a period of several months, I did periodic and detailed parametric monitoring of DC and AC currents,
Some people seem to do better, even getting them to replace the defective-but-not-yet-dead units. I've never been successful in doing that. That's why I'm still sitting on a half dozen or so defective units with no idea when they will be replaced.
This is somewhat contrary to my experience. I had a degrading M215 that was obvious to me by continuously monitoring my array with Enlighten Manager. Of course, I waited till I was positive by monitoring AC currents, voltages, power inputs and outputs associated with this one microinverter. By doing this, eventually, it was intuitively obvious the inverter was slowly degrading, whether by comparing calculated power conversion efficiencies to the Enphase M215 specs (in particular, >96% CEC efficiency) or by simply studying graphical representations of all the other modules in the array and compared them to this one particular "odd ball" module's location.
When I contacted Enphase, they insisted on an seemingly unnecessary troubleshooting procedure. This required me to call in the Installer to swap out inverters; the one in question to the location of one of its neighbors, thereby connecting it to a neighboring PV panel to eliminate the possibility of a defective panel in its original location.
I did not feel this was necessary, because to measure the internal efficiency of a microinverter, all that is needed is compare the input power to its the output power and a common units of measure (watts). It does not matter what the input is as that is just a reference point for the conversion. If the ratio of input to output power can be observed to slowly increase (or conversely, in terms of efficiency, for the output power to input power to slowly decrease), then the inverter must be going bad. As such, even as a day to day efficiency calculation, (as an aside, this calculation must be done manually, as EM does not do it for you and probably for obvious reasons), it can be easily determined mathematically what is any given inverter's input to output conversion efficiency.
Some of my 17 inverters were determined to be on the high side (>95% efficient), some on the low side, but only slightly <95%, and this one particular inverter, not even a year old, <85% and slowly dropping over time. On average it was a full 10% lower than the rest. RED FLAG!!!
Nevertheless, Enphase Customer Support insisted on the swap, so I called my system Installer and they did that just as Enphase instructed, no questions asked. The finding? The same suspect inverter was now misbehaving while connected to its neighboring (known good) panel just as before the panel swap. BINGO! Now I have "proof" that the inverter is obviously unhealthy and not meeting Enphase specs. However, Enphase was all too quick to falsely ASSUME it was some sort of shading issue with my array. This too, could have been easily disproved by simply using Enlighten to confirm that to be a non-issue. Such absurd conjecture should be been an embarrassment to Enphase to have even been suggested at this point. Again, a microinverter's INTERNAL conversion efficiency has nothing to do with its input conditions.
To my amazement, Enphase was still unconvinced, but they reluctantly agreed to keep tabs on the suspect inverter (now using Enlighten to remote monitor it, as I had been doing, over a couple of additional weeks. This was to observe for themselves it was slowly degrading, which of course, it did by continuing to drop in efficiency by a few additional (and measureable) percentage points. Then, and only then, did Enphase FINALLY become convinced it was defective and thereby conceded to a warranty replacement. Unceremoniously, that took place over the next few weeks via a typical RMA process. PRESTO!! The problem immediately disappeared the day the unit was finally replaced with a new M215.
The moral of the story, if not for the full capabilities of Enlighten Manager, I would not have noticed the problem with a single M215 falling behind the performance curve compared to the others in the same array. Enlighten is a very powerful diagnostic tool provided the user has a basic understanding of Ohm's Law and good pair of eyes to notice trends in the graphically shaded module to module displays. I only wish the company that developed it, was more inclined to use it for troubleshooting themselves. Unfortunately, EM would be a much more effective tool if it embedded each micro's internal efficiency calculation in its graphical and/or tabularized performance measurements. Of course, this will never happen because then warranty claims may suddenly jump up to an much more unmanageable level. :mrgreen:
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