the best wire size to use from my solar panels to the charge controller

Re: the best wire size to use from my solar panels to the charge controller

Welcome to the forum Petaja!

Assuming you have checked the Voc-cold (voltage open circuit cold) with the maximum input of the Outback charge controller (around 140-150 VDC--Cold solar panels output higher voltages, but you are, I guess, are in Jamaica which is not very cold)... Then

The typical voltage drop is from around 3% to 1% (3% maximum recommended for nominal wiring and not "too much" energy loss and self heating to 1% which is about the cost effective minimum voltage drop--Where you are spending too much money on copper for marginal gain in efficiency).

• 50.78 Vmp * 2 = ~102 volts Vmp-array
• 102 volts * 0.03 drop = 3.1 volts maximum drop
• 102 volts * 0.01 drop = 1.0 volts minimum cost effective drop
• 6 parallel strings * 4.92 Amps per string = 29.52 amps Imp-array

Using a generic voltage drop calculator and 60 feet of one way wiring run (some calculators use round trip distance--So double check your calculator's requirements):

• 29.52.amps @ 60 foot wire run => 8 awg gives 2.7 volt drop
• 29.52.amps @ 60 foot wire run => 3 awg gives 0.8 volt drop

Based on your array and the nominal design specifications, somewhere around 8 to 3 AWG cable would be recommended. You can use heavier or lighter AWG wiring, based on your needs and available funds. In the US:

• 29.52 Amps * 1.25 NEC derating for wiring/breakers = 37 amps branch wiring/breaker minimum rating

So, you would want cable designed for a minimum of 40 amps. 8 AWG would be minimum wire size for a 40 Amp circuit.

Note, that for parallel strings of solar panels--You would need somewhere around 10-15 Amp fuses/breaker per string (use a "combiner box" -- Basically similar to wiring a normal Breaker Panel "backwards" to combine current from multiple circuits). Check the specifications for the solar panels for the Maximum "series fuse" specifications.

-Bill