Thanks very much - appreciate all the great info and advice!
Sounds like the M215/M250s are about as reasonable a choice as one can make for any newer technology, with the central inverter being a bit more predictable due to being older known tech. SolarEdge seems interesting, though seems combine the risks of a central inverter with many more points of failure. Their new system with no electrolytic capacitors -- is that expected in weeks or months? I figure getting grandfathered under NEM 1.0 and starting saving on my PG&E bills is probably a bigger factor for proceeding vs waiting.
RegGuheert said:
Enphase insists on an installer doing warranty work unless it was self-installed. I suspect SunnyBoy might do the same, given there is additional complexity in a central-inverter-based system (DC wiring in addition to the AC).
How is this handled if the installer goes out of business? A bit less of an immediate concern now with the extension of the ITC, but still could be an issue in 10 years (or maybe just if the owner decides to retire). Is it also the case that I won't be able to see as much output information from my system if I'm not the registered installer? Should I insist that my installer list allow me to register as the installer, to protect myself down the road? Given that Enphase apparently won't even talk to owners anymore?
Would I be able to get an eBay replacement online, producing, and monitored without Enphase's cooperation?
With Enphase it seems the exposure is both Enphase or the installer going out of business. If my solar installer goes out of business, can I hire another "solar professional" to take their place?
I have some doubts about any software service provider being around in 20+ years, technology and business moves too fast, but from what I understand both the SMA and Enphase allow rudimentary production monitoring locally (even if their service is down). Does SolarEdge?
I know Enphase's stock price has been in the tank, but is there actually large concerns of them becoming insolvent? It seems like at least with a central inverter, I can swap out with any brand down the road, without discarding still working hardware or being able to obtain no-longer in production micros. Though I suppose with 12-15 micros it's less of a disaster if I have to replace all the micros for compatibility reasons, vs a 30 or 70 micro install.
Summarized, the tradeoffs seem to be (and please correct me if I'm off):
Enphase M250:
+ longer warranty (25 years on the M250s, though only 2/5 years on the Envoy?)
+ potentially cheaper out-of-pocket replacements if only a couple micros fail over time, assuming supply is available
+ flexibility for adding an additional panel later (minor - I believe PG&E limits be to 10% increase under NEM 1.0, which would be ~1 panel)
+ individual panel performance monitoring
+ better shading performance should any issues crop up (likely not a factor for me)
+ lower voltage (potentially safer)
- unknown outlook on Enphase - may not be around to honor warranty or produce more hardware
- if unable to get replacements on eBay (everyone buys them up), may have to replace entire Enphase string/system
- won't deal with me as an owner, big risk if I need support and my installer is out of business?
SMA:
+ company outlook seems better, likely to be around for the length of the warranty
+ less components
+ when it needs replacement, can pick any central vendor/product as a replacement, no compatibility issues with existing hardware
- shorter warranty, likely replacement out of warranty in 12-15 years.
RegGuheert said:
Personally, I find microinverters to be safer. SolarEdge claims their approach is just as safe. Maybe so. But the inability to draw a high-power arc from a single PV module is comforting to me.
This primarily being a factor of 600V vs 240V? Or is there something else inherent?
One more related question -- I'm redoing my roof (flat roof w/modified bitumen), and have the option of having the solar installer coordinate with the roofer to install the mounts during that process. The roofer wants $50 per additional penetration flashed, which certainly raises my effective $/watt. Is this a worthwhile premium to avoid penetrating a brand new roof and have it all covered under the roofer's guarantee, or are Quick Mount PV installs from a competent installer pretty bulletproof? The solar installer offers their own more limited roof guarantee, but I can imagine the finger pointing should there be an issue.