Why Nominal power ratio BEST at 87% on SMA sunny boy inverters? Charlotte NC GT pergola 5 deg SW.

rollandelliottrollandelliott Solar Expert Posts: 834 ✭✭
I'm rusty at doing GT inverter sizing. Why does SMA design software show the Nominal power ratio is Greenest around 87%?
 I assume that is a good compromise between not over stressing the inverter and getting good solar production? I know it is best to keep inverters inside conditioned space, but they have to be mounted to side of house for this location. Maybe I will pour a little concrete pad and make an insulated 2x4 structure around them which vents to the inside of the conditioned air space latter on. 

This is for a GT installation 30 sunpower 360w panels and 16k and one 5k older model sunny boy inverters, charlotte, NC under pergola 220, south west orientation 5 degree slope. 


  • billybob9billybob9 Registered Users Posts: 141 ✭✭
    If you look at your SMA 5.0 Amperage it is 30A. Which mean you will use a 30A breaker on your backfeed  panel breaker. Doing the math for 16x300W panels seems to be 40A so this maybe the "good compromise" that's going on. I'm going to try to shade my Inverter too. This goes for the controller also which is subject to moisture.
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