RegGuheert
Well-known member
You're right, it does sacrifice about 9.5 years of warranty on each unit that becomes a cold spare. (The M190s only came with a 15-year warranty while the newer units come with 25.) But I will point out that each time an M190 fails, it gets replaced by a new, fourth-generation unit that has no more warranty, but that likely has a 25-year life.ltbighorn said:It seems like you're preferring to cycle out units that still have warranty left on them for new units (characterizing it as "extending the warranty by X years"), but I presume that essentially sacrifices the warranty on the existing ones.
Getting them off my roof is the primary motivation. The MTBF of the original M190s is nearly 20X worse than that of the fourth-generation Enphase microinverters. Repairs on my roof are significantly more difficult than those done in the field, which are trivial.ltbighorn said:What's your thinking behind that? Is it primarily a side-effect of trying to get more failure-prone M190s off your house roof, or is it also for its own sake?
The issue is that the PV modules in the field are 72-cell units while the ones on the roof are 60-cell modules. The original M190s will work with either type of module, but the fourth-generation microinverters (including the M190IG replacements that Enphase is now shipping out) will NOT work with the 72-cell modules in the field. So I had a choice: spend the next 10 years replacing M190s on the roof one-at-a-time as they failed and end up with a dead field array after about ten years or purchase new, high-reliability inverters for the roof and create a stockpile of 72-cell-compatible microinverters that I can swap in as they failed. Since ALL of the M190s are likely to fail before ANY of the fourth-generation units fail, my stockpile of M190s will slowly be converted to fourth-generation M190IGs as Enphase replaces failures.ltbighorn said:If not the former, then why keep so many spares right now, vs. buying them later?
Yes, but primarily for the 72-cell-compatible microinverters. 60-cell-compatible microinverters will be around for many years to come. The original M190s are both less reliable AND they have a shorter design lifetime. As a result, the quantity available is shrinking rather quickly. In addition, the quantity manufactured was significantly lower than the number of fourth-generation inverters. Sure, you can purchased used M190s on eBay, but why would anyone want to do that? Used Enphase inverters carry NO warranty, so you risk getting a unit that is dead or malfunctioning or will be soon. OTOH, I have been able to purchase NEW fourth-generation M215IGs with 24 years or more of warranty remaining on eBay. The last 16 NEW M215IGs I purchased were under $100 shipped!ltbighorn said:Are you concerned that secondary supplies will dry up?
As it stands, I currently have 37 original-style M190s (not counting the four that I sold show ever in the Mountain Array). 12 are in operation in the Field Array. Of those 12, 11 are currently malfunctioning but not badly enough to get Enphase to send replacement hardware. Enphase requires energy harvest over one week to be below 90% of their neighbors to warrant replacement. (I told my wife these have malfunctioning inverters been "put out to pasture". ) The 25 cold spares were all functioning properly when they were removed from service, so I know their condition when they go back into service.
The bottom line is that I am now very hopeful to get an additional 25-to-30 years out of all of the equipment that I currently have and With some good fortune, that will only entail a small number of future trips onto my roof.