I downloaded SunnyDesign software from
I've only fooled around with it for a little bit, but I have a few questions, refer to screen shots below please.
The first photo shows the entire system design.
The second photo has some summary numbers and I'm wondering how I can improve the PERFORMANCE RATIO = 85.6%
Help file says:
I found this document too which I need to read:Performance ratio
The Performance Ratio (PR) is stated as ratio between the nominal yield and the target yield of the PV
plant. It thus shows the proportion of the energy that is actually available for export to the grid after
deduction of energy loss (e.g. due to thermal losses and conduction losses ) and of energy
consumption for operation. The closer the PR value determined for a PV plant approaches 100 %, the
more efficiently the respective PV plant is operating.
The last photo has a Cable diagram that I don't understand at all.
The help file gives the following explantion of terms:
How does the software know how long the wire run is?Graphic of cable distribution
The graphic should help to become orientated with cable dimensioning. The graphic
shows where the cables run in the planned PV plant and at the terminal to the power
distribution grid of the DC lines, the AC1 lines and the AC2 lines:
• "LDC" is the simple cable length from the inverter to the first PV module in the string.
• "LAC1" are the cables from the inverter to a possible sub-distribution.
• "LAC2" are the cables from a possible sub-distribution to the feed-in point.
How did it come up with 16 AWG?
My calculations show the following
Two strings = 16.24 Amps
16.24x1.25(safety factor for overload) x1.25(safety factor for excess production) = 25.4A which is 10AWG wire!!!
Thanks for any help. You're probably wondering why I am using a program if I can do the calcualtions myself? It's the first time I'm putting together a grid tie system and I just wanted to double check everything. Any help is appreciated.