How to size a PV array for the FLEXmax charge controller

[raysun]

This gets asked a lot. For the FM60/FM80:

https://atl.my.site.com/OutbackKnowledg ... controller

[jtzako]

Funny thing.. my recent solar array is 3120 total watts. However, recently I saw it producing a bit over 3700 watts. I'm guessing its a combination of higher altitude (9200ft) having a lot more solar energy, and some edge clouds reflecting more light into the panels. Definitely good I did not go closer to the 4kw my FM80 can handle when sizing the array.

[raysun]

Funny thing.. my recent solar array is 3120 total watts. However, recently I saw it producing a bit over 3700 watts. I'm guessing its a combination of higher altitude (9200ft) having a lot more solar energy, and some edge clouds reflecting more light into the panels. Definitely good I did not go closer to the 4kw my FM80 can handle when sizing the array.

Yes, I see that on occasion. 3.5kW array, typically producing 2.5kW when hot. During "weather events" with passing clouds, and even more, with light rain showers that suddenly cool the panels, 4kW+.

[SandyP]

Funny thing.. my recent solar array is 3120 total watts. However, recently I saw it producing a bit over 3700 watts. I'm guessing its a combination of higher altitude (9200ft) having a lot more solar energy, and some edge clouds reflecting more light into the panels. Definitely good I did not go closer to the 4kw my FM80 can handle when sizing the array.

As an added peace of mind for those that have "fully loaded" their FM60/80 charge controller will solar panels, you can change the max output to be just below the rated output. The FM will then regulate its output to be below that value whilst if you leave it at the default maximum it will not.