Thinking of Doubling the Number of Panels on my System

I understand this is a DIY install but I wonder what your POCO agrees to considering the amount of kw you have installed

A decade ago I did exactly that, coupling twice as many panels
to the original permitted inverters. Perhaps simpler here since I
use string inverters. Since systems are rated by AC capacity
connected to the grid, this does not effect my net metering contract.

To avoid overloading the inverters, the panel orientation was split
between mostly east and mostly west. Instead of overloading the
inverters at solar noon, output is leveled over a longer time. So
peak power is unchanged, but energy collection per day is increased.

Under clouds, the light is dispersed, panel alignment is not critical.
It appears my cloudy day output is roughly doubled. With some
tuning, the inverters are kept just at clipping up to 8 hours on sunny
days, for most months of the year. Bruce Roe

NScurve.jpg

On the other forum, you seem pretty convinced the Enphase inverter will limit maximum current. Bruce intentionally keeps array current under inverter max current by using east west orientation.

I assume you are collecting enphase data from two paralleled panels into one inverter for the data listed above. This is November and you aren't getting anything close to Impp. Try the same experiment in June.

Dealing with min max and other specs most of my professional career, in my experience these are limits you want to stay away from, not limits that the devices will enforce. I.e. if you want a current limiting device, you buy a current limiting device not a current meter.

Side bar question to those considerably more in the know than me: Inverter sizing. Is an inverter PHYSICALLY sized to handle x-number of panels/kW or LOGICALLY sized through the configuration of the OS? ...or both?

Just asking for my own edification. I had been contemplating if I would need / could get one more array of 4 panels on an open, Western facing roof line.

SteinVT , I see on the other forum you built your ground mount system yourself. Nice job. I wish I had the room to do such a system.

I did a little more research into Enphase 7 microinverters and found that Enphase expects the installer to ensure microinverter voltage and current maximum values are not exceeded through panel selection/design. I believe two panels on the same plane connected to one microinverter would violate the Enphase Installation and Operation Manual guidelines (15 amps max DC input).

The member that suggested I post here was right on. Thanks everyone for their comments.

I will try and respond to everyone:

SunEagle - I don't think that would have violated any agreement as I wouldn't every exceed the permitted levels. If I remember correctly it was based on inverters.

Bruce - You did exactly what I was thinking. If I were to put the second array, I was going to split it east-west for the same reasons. Your string inverters are the difference.

Oregon_Phil - Just to clarify, the data I presented was an excel simulation. I haven't changed any of my hardware. Thank you so much for pointing out the maximum DC current rating in the manual, I missed that. That's enough for me to drop this project.

Rade - I hope folks more knowledgeable then me will answer, but my guess it is both. The control loops will limit the power going through the system, but the design of the board must be sized to handle the current.

Bottom line, I am going to drop this project. I think it probably would work fine on the low light days, but could be a problem when the sun comes out. And then I think it could go bad fast and would definitely void any warranty on the inverters.

Thanks again to all that answered - Mark