Use "Rated PV Array Current" or "Battery Charging Current" for wire calculations

[Hinterland Ranch]

What value should be used for calculating the wire gauge from PV Combiner Box to Charge Controller (Classic 150)?

Thanks in advance.

[Westbranch]

for that exercise you use the PV rated values, Amps and Voltage.
Iff series  connected Volts @^# but not amps for each additional panel.
hth