The site has 3s3p. Two of the strings are identical, 1125W @ 103.5 Vmp. The third string is 1200W @ 93 Vmp & mismatched by ~10v @ Vmp. As you can imagine the inverter MPPT is tracking wildly.
So I added a forth panel in series with the 1200w string. Except that this single extra panel is wired through a buck converter and two series blocking diodes. The buck converter is set to ~12v and is bypassed by a single diode. (See picture)
The MPPT still tracks wildly but the power output remains relatively constant. The power and voltage charts were sampled for two minutes under varying cloud conditions.
Food for thought anyway
So I added a forth panel in series with the 1200w string. Except that this single extra panel is wired through a buck converter and two series blocking diodes. The buck converter is set to ~12v and is bypassed by a single diode. (See picture)
The MPPT still tracks wildly but the power output remains relatively constant. The power and voltage charts were sampled for two minutes under varying cloud conditions.
Food for thought anyway
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