Robert Bruninga via EV wrote:
Still not true. The output of microinverters is at 240 VAC and the average current in the wires will be double as the same number of panels at 480 VDC.
But each microinverter has its own wire. The total current may be twice as much in a 240v system as in a 480v system; but there are twice the number of wires, each half the size. You wind up back where you started.
Further, AC peak currents are 1.4 times higher than DC so the peak currents (where the losses are) are 2.8 times greater
No; AC voltages and currents are normally expressed in RMS (Root-Mean-Square). RMS voltages and currents have the *same* effective values, voltage drops, and losses as DC. 120vac and 120vdc are completely equivalent.
The difference in buying #6 wire instead of #12 is only $180 versus $30. Or you can ignore the extra 10% or so losses and use #10 wire. But over the life of the system (20 years) the losses in your solar system can add up to many thousands of dollars.
Sure; it's basically an economic decision. How much can you afford up-front, to reduce long-term losses? It's further complicated because when you eventually scrap the system, much of the cost of the copper is recoverable.
Note that this is the EV discussion list. Besides these tradeoffs, weight is also an issue. You may be ahead by deliberately undersizing the wire to save weight. The benefit from weight reduction can exceed the efficiency loss. Racers know this well!
Maybe I am just being nitpicky, but my solar arrays are all over my yard and house. Some runs are over 300 feet! (shortest is maybe 60').
Ah; no wonder you are so concerned with wire lengths. I definitely consider 60-300 feet *long* runs! The PV panels on my house are only 20' from my circuit breaker panel.
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