Another solution to use thinner cables is to start with more volts from the pv.
Because the loss in the line is counted in volts per meter, so if you must go 10 meters away with 12V and you loose 1v per meter ( It's not that much in reality for example only) you end with 2V. If you start with 120V, you still get 110V at the end. as P = V x I , I = P/V, If P is 120W and V is 12V, 120/12=10Amp , If V is 120V, 120/120=1Amp .
Why must aluminium be 1.61111 times bigger than copper? Sorry for the mistake in previous post.
Because of the resistivity.
Al: 0.0278 Ohm x square mm/ meter
Cu: 0.017 Ohm x square mm / meter
or maybe more obvious, the inverse, the conductivity.
Al: 36 meter/(Ohm x square mm)
Cu: 58 meter/(Ohm x square mm)
58/36=1.61111
so a copper wire of 58 meter long and 1 square mm surface as the same resistance as a wire 116 meter long and 2 square mm surface.
For the same resistance an aluminium wire would be only 36 m for 1 square mm.
How much is the diameter of 1 square mm?
S = pi x D squared / 4
D squared = 4 S / pi
D = square root of 4S / pi
4/3.1415927= 1.27 so much decimals for pi is for the show. 3.14 is close enough. :D
square root of 1.27 = 1,127 mm that you can measure with your caliper.
for 4 square mm, common pv cable.
16/3.14=5.095
root=2.26 mm
16 square mm = 4.515 mm
35 square mm = 6.672 mm
Well good night, or good morning.
Ps: if you prefer inches 1 inch is 25.4 mm
You can redo my math, because I make mistakes.