KJINTF wrote:
Hi Jim
What I am looking for is "MPPT will have a 5% performance drop. It's all relative, but mppt needs the big cables."
This I do NOT agree with
Any voltage drop you eliminate in an MPPT system, you get to recover because P=I*E - E gets bigger (I does offset this some by getting smaller though, but not enough to dominate until V exceeds Vmpp).
So all things being equal, bigger cables mean less voltage drop mean more power. But once you get to 2 panels, it all changes because you can now instead put them series with MPPT and get a benefit, running less current but more voltage through the cables for less power loss. So MPPT does allow you to run higher voltage, and higher voltage makes wire size less important than parallel wired panels into MPPT.
But generally I think it is a fair statement that MPPT will benefit more from big cables than PWM, because MPPT can actually make use of the extra voltage to create more power, where PWM often just cannot take advantage of the reduced voltage drop from big wires (especially under high output conditions).
Jim
