GetOffYourGas wrote:Now that the snow is melting, I have begun watching my panels again (it's really boring to see 0Wh produced every day).
We've been in the "Nor'easter Hole" this year and only one of the four dumped on us. Our array had snow on it only for about two days in March and we beat our previous March production record by 61 kWh.
GetOffYourGas wrote:I noticed that another M215 inverter has bitten the dust. Looking through its history, it stopped reporting on December 19, 2017 at 10:20am, and has not produced anything since.
I recorded that as a failure of one of your original inverters on the date you gave.
GetOffYourGas wrote:I contacted my installer, and he says that they are in high demand because of the large number of failures (which of course doesn't match Reg's history). He expects my replacement to arrive in about 60 days. That means I'll miss out on some of the best production months of the year.
I think the real issue is that the M215s are no longer a standard product so they probably only produce a batch now and then.
GetOffYourGas wrote:I also noticed another inverter which operates normally until it is in direct sunlight. On cloudy days, it will produce the same 50-60 W as the rest of the panels. On sunny days, it will be producing 2-5 W while all other panels are producing 180-200 W. I have never seen this failure mode. It clearly isn't meeting the spec, so I've reported it to my installer as well. I assume enphase will replace it.
I'm sure they will replace it. The key is that it needs to produce less than 90% of its neighbors over a 7-day period. You didn't mention which type of inverter this was so I recorded it as a failure of one of the original M215s, just like the other one.
I will add two new M215IGs once those are installed.
Assuming these were both failures of the original M215s you had installed, you now have had 7 out of 16 fail after about 6.3 years of service. The spreadsheet is not overly friendly for calculating the MTBF of your system since each replacement is with a different type, but I did the calcs and I come up with 92.33 total device years and an MTBF of only 13.2 years
after seven failures for the original M215s. You only have about 8.2 device-years on your M215IGs and no failures, so MTBF is really not established there.
By way of comparison, I have seen the following MTBFs in my system to date:
- M190s: 249 device-years - 6 failures - MTBF = 35.5 years
(These are out of service now, but I intend to run 12 this summer.)
- M190IGs: 2.7 device-years - 0 failures - MTBF = ??
- M215IGs: 75 device-years - 1 failure - MTBF = 75 years
- M250s: 32 device-years - 0 failures - MTBF = ??