wheisenburg
Independent Solar Consultant
So first to be clear here, my IQ8+ inverters work perfectly while grid tied. I have had issues with getting them to work when AC Coupled behind my Schneider WX Pro Inverters when they have lost the grid and are in grid forming mode. Enphase fixed the worst of these problems with a firmware upgrade, so now it is a matter of getting this fine tuned and working optimally.
After some amount of experimentation, I have my AC Coupled IQ8s up and limping. I have three strings of micros with a total of 35 * 350 Watt DC panels, feeding 35 IQ8+ rated at 295 watts. They are AC coupled into dual Schneider XW Pro 6848 inverters. So with one string running everything is working perfectly. With more than one string running the IQ8s were shutting down immediately with the IEEE 1547 2015 grid profile. I adjusted the max charge rate setting and also changed to the IEEE 1547 2018 grid profile. Apparently the IEEE 1547 2015 grid profile does not support incremental Frequency Watt curtailment.
So at this point when running more than one string when the batteries are getting near to full, I can see the frequency rising and the watts decreasing. At some point ALL the IQ8s will shut down. After 5 minutes the IQ8s will start up and produce power again. This is a vast improvement, because until recently I couldn't get power production at all when the inverters were not grid tied. I think there is still a problem with the profile, possibly with the "Slow over frequency" disconnect. I have seen some profiles where this is set to 61.5 Hz and 300 seconds. With the current grid profile the Frequency Watts doesn't start until 60.5 Hz and continues up to about 62 Hz, but before that point the IQ8s will shut down. So I need a profile that either has a steeper Frequency Watt Curve or where it allows the inverters to continue to operate to at least 62 Hz.
So does anyone out there have AC Coupling working Off Grid with IQ8s? If so what Grid Profile are you using? For that matter, if you have a grid profile that works with IQ7s, I would like to hear about that too.
After some amount of experimentation, I have my AC Coupled IQ8s up and limping. I have three strings of micros with a total of 35 * 350 Watt DC panels, feeding 35 IQ8+ rated at 295 watts. They are AC coupled into dual Schneider XW Pro 6848 inverters. So with one string running everything is working perfectly. With more than one string running the IQ8s were shutting down immediately with the IEEE 1547 2015 grid profile. I adjusted the max charge rate setting and also changed to the IEEE 1547 2018 grid profile. Apparently the IEEE 1547 2015 grid profile does not support incremental Frequency Watt curtailment.
So at this point when running more than one string when the batteries are getting near to full, I can see the frequency rising and the watts decreasing. At some point ALL the IQ8s will shut down. After 5 minutes the IQ8s will start up and produce power again. This is a vast improvement, because until recently I couldn't get power production at all when the inverters were not grid tied. I think there is still a problem with the profile, possibly with the "Slow over frequency" disconnect. I have seen some profiles where this is set to 61.5 Hz and 300 seconds. With the current grid profile the Frequency Watts doesn't start until 60.5 Hz and continues up to about 62 Hz, but before that point the IQ8s will shut down. So I need a profile that either has a steeper Frequency Watt Curve or where it allows the inverters to continue to operate to at least 62 Hz.
So does anyone out there have AC Coupling working Off Grid with IQ8s? If so what Grid Profile are you using? For that matter, if you have a grid profile that works with IQ7s, I would like to hear about that too.
