You don't list your location, but using an online calculator shows your going to close to exceeding the inverters never exceed ratings
You have 12 panels in series rated at 45.34V at 25C ( 77F ) if in the morning you have 0C ( 32F ) the string will be at 580V.
So you need to reduce the number of panels in series it would seem
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Thank you for the response. I think yes it would probably be best to reduce the string size as a safety net. I didn't use the same calc, but I got similar values. the extreme min temp in SC I used called for -11 C in my area. Although like I mentioned, sub freezing temps are pretty rare. this temp would be 12 deg F, which I can only remember once or twice in my life. in any case, my calcs showed 593 at extreme min for Voc, obviously dangerously close to never exceed voltage, but in my mind I just can't see sizing with one less panel to account for extreme min temp, with full sunlight, and full voltage output from panels. Maybe I'm naive, but just my thinking, and if weather was ever marginal, the pv disconnect is always there.
in my case from morning of 12/1 that caused the issue, I know the voltage never exceeded the max both from data logging and physical measurement with a meter. I saw 515v pretty steady with the meter when troubleshooting after the "banging". Signature didn't offer me much as I mentioned bc I wasn't in front of the unit, but they suspect MPPT 2 may have shorted and that's the first thing I'll check when returning home.
This is the data from 11/30 when I was fat and happy and seeing my new install work flawlessly, the temps were almost identical (low of 29 F / -2 C )
and the data from the morning it went "bang", the spikes later in the day were me troubleshooting, and the final spike in pv2 voltage is with one panel removed from the string.
the morning of 11/30 was bright and sunny, the morning of the failure was a bit more haze, but still some sun, and pretty thick frost on panels.