Panel to Solar Controller Wire Size
As some of you already know, I'm piecing together a solar system. Controller is a Morningstar 45A PWM. Panels will be two 12V 150W wired in parallel. I'm going to be using a combiner box on the roof, ...
Forum Discussion
Hi Mena,
I generally recommend designing a system around 2% (or less) voltage drop…
Taking your 450W figure (I used 35A), and assuming 40 feet of wire (20 feet each of + and - conductors) you will need to 6ga wire to stay at 2%. 4ga would be slightly better, but IMHO would not worth the extra cost. With the 6ga wire you can safely select a fuse in the neighborhood of 75-80A to keep losses low and still have a good margin of safety.
In terms of ampacity alone, you would be fine going as small as 10 or even 12ga… but personally I'd spend the extra $$$ to keep the voltage drop in the 2% range.
Cheers
-Mark
I generally recommend designing a system around 2% (or less) voltage drop…
Taking your 450W figure (I used 35A), and assuming 40 feet of wire (20 feet each of + and - conductors) you will need to 6ga wire to stay at 2%. 4ga would be slightly better, but IMHO would not worth the extra cost. With the 6ga wire you can safely select a fuse in the neighborhood of 75-80A to keep losses low and still have a good margin of safety.
In terms of ampacity alone, you would be fine going as small as 10 or even 12ga… but personally I'd spend the extra $$$ to keep the voltage drop in the 2% range.
Cheers
-Mark
