Panel combination options and disconnects

[Bluedog225]

Good afternoon,
I’m working on the layout for my arrays. They will be about 50-75 feet from the cabin. Off-grid. With the controllers, inverter, batteries at the cabin. This proposal uses about half my panels (used). And can be adjusted as needed. The east and west arrays are configured to fully carry my air conditioning load in the morning and evening as a solar pass through (fat production curve).

I have three questions;

1. What make sense in terms of combining these arrays? I’m leaning towards Option 2. It would save on wire cost and take better advantage of the charge controller capabilities.

1. Does MPPT work as I’m intending with an east and west array on one input?

1. Do I need combiners and disconnects at both the arrays and at the cabin? It seems wrong not to have one in both places.

-1 string of 9 panels in series (9 panels * 40.1 volts = 360.9 volts per string at 9 amps); South facing
-1 string of 9 panels in series (9 panels * 40.1 volts = 360.9 volts per string at 9 amps); South facing
-1 string of 6 panels (6 panels * 40.1 volts = 240.6 volts per string at 9 amps); North facing
-1 string of 6 panels (6 panels * 40.1 volts = 240.6 volts per string at 9 amps); South facing
-Nominally 9000 watts
-Panels-295W, Voc 40.1A; Pmax V 32.7; short-circuit current 9.52A; current at Pmax 9.03; max system voltage 1000V

Option 1:
-Run as is. 4 separate strings to the MPPT. 360 volts; 9 amps per string.
-Use a Victron Smart Solar RS 450/200; (450 volts/100 amps); 4 MPPT trackers. Looks like an SMA Sunny Boy would also work.

Option 2:
-18 panels (9 panels in series/2 strings in parallel): 360 volts 18 amps
-12 panels (6 panels in series/2 strings in parallel): 240 volts; 18 amps (east and west)
-Use a Victron Smart Solar RS 450/100 (450 volts/100 amps); 2 MPPT trackers

It looks like the Midnite MNPV4HV 3R Deluxe is the right product for the combiner/disconnect box. Is this correct? Or is there another product line I should be looking at? I ask because these are not cheap.

Thanks!

 

[OzSolar]

Here's what SMA advises about Polystring Operation. (array's with different orientation on the same MPPT) Hopefully you can glean something useful from that.

High voltage DC disconnects are expensive. No easy way around it that I know of. I've use this MNPV12 with touch safe tilt out fuses from Midnite Solar many times and it's been a good solution.