ddxv
New Member
I am trying to calculate the max amps for breakers and for wire guage estimates, but I realized the way I was calculating it for bifacial lead to some questions.
First, is it correct to calculate max amps leaving panels as watts/voltage? While this makes sense for the rated 440W, for the bifacial total of 550W it no longer aligns with the other way of Strings * Max Power Amps.
Amps = number of strings * (rated 440W / VMPP)
Amps = number of strings * (bifacial max watts at 550W / VMPP)
Amps = number of strings * Max Short Circuit Amps
So if I am selecting a breaker, would it be the red or green for each string?
12.68 * 1.25 = 15.85
vs
15.85 * 1.25 = 19.81
And would this also hold true for estimating the total amount leaving the combiner box for 2 strings:
25.36 vs 31.69
Panel specs if I'm missing anything:
First, is it correct to calculate max amps leaving panels as watts/voltage? While this makes sense for the rated 440W, for the bifacial total of 550W it no longer aligns with the other way of Strings * Max Power Amps.
Amps = number of strings * (rated 440W / VMPP)
Strings | Series | Count | VMPP | VOC | Volts From Panels | Max VOC | Watts | Max Watts | Total Amps |
2 | 8 | 16 | 34.71 | 41.51 | 277.68 | 402 | 440 | 7040 | 25.35 |
Amps = number of strings * (bifacial max watts at 550W / VMPP)
Strings | Series | Count | VMPP | VOC | Volts From Panels | Max VOC | Watts | Max Watts | Total Amps |
2 | 8 | 16 | 34.71 | 41.51 | 277.68 | 402 | 550 | 8800 | 31.69 |
Amps = number of strings * Max Short Circuit Amps
Strings | Series | Count | Max Power Amps | Short Circuit Amps | Strings * Max Power Amps = Amps |
2 | 8 | 16 | 12.68 | 12.88 | 25.36 |
So if I am selecting a breaker, would it be the red or green for each string?
12.68 * 1.25 = 15.85
vs
15.85 * 1.25 = 19.81
And would this also hold true for estimating the total amount leaving the combiner box for 2 strings:
25.36 vs 31.69
Panel specs if I'm missing anything: