Calculations

[Bill Perrino]

I have 12 M215 Enphase micro inverters. so

0.9 x 12 = 10.8A

10.8 x 125% = 13.5A

and 0.9 x 6 = 5.4A

5.4 x 125% = 6.75A

Therefore, there is an increase of only 6.75A on each phase, not 13.5A.
Does this make sense or am I missing something?

Thank You, Bill

 

[SolarPro]

Here's the relevant enphase white paper:

http://enphase.com/wp-uploads/enphase.com/2011/12/EnphaseAppNote_Circuit_Calculations_M215.pdf

Each 215 outputs 240 Vac. So your math is correct up until the point you divided the current per line in half.

There are 12 inverters connected line-to-line at 240 V at 0.9 A per inverter.

 

[ggunn]

I have 12 M215 Enphase micro inverters. so

0.9 x 12 = 10.8A

10.8 x 125% = 13.5A

and 0.9 x 6 = 5.4A

5.4 x 125% = 6.75A

Therefore, there is an increase of only 6.75A on each phase, not 13.5A.
Does this make sense or am I missing something?

Thank You, Bill

Yes, you are missing something. The current does not divide between phases, the power does.

Think of it as a loop with the same current in both phase conductors, just going in opposite directions.