Tinkeringcaveman wrote:I have more work to do, but still preliminarily believe heat is the cuplrit.
If this was the case, we should be seeing a lot more failures in Arizona. Here's a site of a fellow in Tuscon I've chatted with:https://enlighten.enphaseenergy.com/pub ... ms/tL4K292
4 separate arrays which have been expanded twice over the years. He has the 7 of the original M175 inverters - the rest are M190s. Only one failure so far after a number of years in the Tuscon heat - and that was one of the original M175 inverters.
Tinkeringcaveman wrote:I have a brown roof, which probably does not help the situation.
Probably not. In my discussion with others a big issue is heat being radiated back through the attic onto the back of the panels. Your attic is probably in the 150F range - similar to the inverter temps. So anything you can do to help cool the attic will also help reduce inverter temps. Properly installed radiant barrier will help keep the heat out of the attic and installed under the panels will help keep the heat from going the other direction and heating up the inverters/panels.
Tinkeringcaveman wrote:I suspect a ground array or post-mounted array would not experience these temperature problems, and would have no qualms about using microinverters there. I am increasingly hesitant to recommend to anyone that they use them on rooftops.
Ground mounted systems will definitely have lower temperatures. But mounting the panels higher off the roof with some spacing between rows will also be effective. 6" off the roof instead of as close as possible as many try to get the panels will reduce temperatures boosting production as well as improving lifetime of the inverters.
QueenBee wrote:The next generation is coming out very shortly.
I managed to grab a copy of the spec sheet (it's called the M250 and will be announced on the 9th) when Enphase accidentally put it on their website. Specs aren't all that different than the M215. Some notable differences:
1. Power output: 240W nominal, 250W max
2. Efficiency improved 0.5%
3. Isolated DC circuit - GEC grounding no longer required for inverter.