ltbighorn said:
Glad to hear it was easy this time, though too bad on the gen 4 numbers.
I'm hoping that number doesn't stick!
ltbighorn said:
That said, with your new spare, do you ever consider testing/burning them in for a few months to make sure they won't suffer from early failure?
Not really. Enphase does that when they manufacture them. That said, this failure DOES indicate that one slipped through undetected.
ltbighorn said:
Somewhat presumes the concern that they might not be around to service the warranty forever.
That is my presumption. But that brings up the real question: Is there something about the new metal cases that caused this failure? If there is, then I should be running the four M215IGs with cans that I bought AND the two 60V M190IGs that I received as spares in 2016. IF I have another failure of a fourth-generation inverter with a metal can, those things will definitely go right up onto the roof!
ltbighorn said:
Also I'm assuming as a replacement, your warranty continues from the date of the originally purchased inverter, not the replacement.
That's right. And for the unit just being replaced, it was manufactured toward the end of 2015. The replacement will be a little bit newer, but not that much, so it doesn't make much difference. However, with the M190 replacements, the story is very different. The M190s that I purchased new only have 9 years left on their warranties, but the replacements are built the same way as new inverters with 25-year warranties, so I'm basically hoping that the old M190s last as long as possible and that I can get more than two 15-year lifetimes out of the M190 plus its spare.
One final point is that the old M190s have electrolytic capacitors in them that fail FASTER if not energized than if they were used every day. OTOH, when they are used, they run hotter, which also tends to reduce their life. While I think they are good for a couple of decades of storage, if any of those old inverters stay in the boxes for more than about 5 years, I will likely swap them out into the field to get their capacitors annealed. In any case, it is probably better to be storing the inverters with no electrolytic capacitors since those should not have similar storage failure modes. My decision to put the M190s into storage had more to do with the fact that the replacements I was getting were not rated for the voltage of the PV modules in the field array. But that reasoning all changed with the shipment of 60V replacements which Enphase started in 2016. Still, if they go out of business, I'm back to where I was wanting spares for my field array.
It will be several more years before we know if this failure was an isolated incident or not. The M190s are the only inverters where I think we have a ballpark number on failure rates (and it seems to be different for different systems).
