Arc fault mitigation.......decided to halve string voltages from 150V down to 75v.

[pullin_gs]

I have a 2KW system (8 250W panels each rated at VOC 37V short-circuit current of 9 amps).
The panels are wired for two strings of 4-panels (4S1P) each. VOC is 150V.
Will instead change to two panel groups 2S2P each. VOC is 75V. Short-circuit current 18 amps.
Fortunately the two MPPT controllers I am using will work fine for 36V 15Kwh batteries....more efficient actually.
Wiring from panels will need to be heavier though. :-(
Will also need to swap out panel-to-charge controller breakers (wish I used fuses!) for two panel groups. :-(
Did I miss anything?

 

[AntronX]

What's the PV to controller wire size and length?

 

[pullin_gs]

12 gauge. About 30 feet from outside junction box...before I just ran series-panels wiring straight to DIN panel inside garage.

 

[AntronX]

12 gauge. About 30 feet from outside junction box...before I just ran series-panels wiring straight to DIN panel inside garage.

12 gauge run per each 2S2P panel group? In this case you got 2.8% voltage drop. It will work but you may have 10 - 20w loss per panel from mppt error due to voltage drop.

 

[pullin_gs]

12 gauge run per each 2S2P panel group? In this case you got 2.8% voltage drop. It will work but you may have 10 - 20w loss per panel from mppt error due to voltage drop.

That is a huge loss. I will definitely have to swap that out. Thanks for pointing that out.
What are MPPT errors due to voltage drop? I'm not familiar with losses (above and beyond the wire losses themselves) introduced by MPPT algorithms.

 

[AntronX]

What are MPPT errors due to voltage drop?

MPPT controller detects incorrect panel voltage and chooses sub optimal voltage/current point. I noticed this with my 30V panels running in parallel.