12x 100W panels into Sol-Ark 12K MPPT

[DIYSolarShed]

Hello all,

I am trying to terminate 12x total 100W panels into a Sol-Ark 12K. Panels: https://www.amazon.com/RICH-SOLAR-Premium-Monocrystalline-Solar/dp/B086ZL9PM8

4x of the panels are ~155ft from the Sol-Ark, while 8x of the panels are about ~120ft away. (See Diagram)



The 4x and 8x panel groups will be shaded at somewhat different times of the morning (until 9:30AM and 10:45AM). I am open to using a Midnight Solar combiner box or similar if that would be an optimal solution. The panels advertise that they include "bypass diodes."

Alternatively, I am open to using lower AWG wire to terminate the panels directly into the Sol-Ark. Using this calc I think that's possible even with the 155ft: https://www.calculator.net/voltage-drop-calculator.html

The Sol-Ark seems to indicate a minimum MPPT voltage of 150V. It seems that 4x of the Rich Solar panels would not hit the minimum, but 12x would.

https://www.sol-ark.com/wp-content/uploads/2020/07/12K-brochure-combined-7-22-2020.pdf

Ultimate Question:

1) Should I terminate all 12x panels into a combiner box, or (because of the shading) is there a benefit to running the 4x and 8x groups with separate wires into each of the two "Solar Strings" that Sol-Ark provides on each MPPT? (Technically 2 full MPPTs and 4x or 6x Solar Strings per Sol-Ark).

 

[DIYSolarShed]

Might have answered my own question, manual states this:
5. Parallel strings per MPPT must be the same voltage, PV1A/B must be the same voltage if both are used (see Fig. E).

So I can't run 4+8 (... unless I do 4S+ 4S 2P ) ?

 

[MisterSandals]

So I can't run 4+8 (... unless I do 4S+ 4S 2P ) ?

In theory it should start out as the same voltage. And differences between the array voltages when one is partially shade is a possibility. Same for any loss in the wiring (its a long run).

 

[DIYSolarShed]

I think it will be simpler to set it up with all 12 panels in series:

18.4 vmp x12 = 220.8v
5.43A

Seems perfectly within spec. I will lose a bit from shading but it will be a simple design.

Any issues with long "serial" connectors between the 4x and 8x panel groups?



Edit: Also found this in the Sol-Ark manual -- Note: separate wires can be used per string, and string minimum is 5 panels or 175V)

So I need at least 10 panels anyway to hit the min voltage.

 

[MisterSandals]

I will lose a bit from shading but it will be a simple design.

Shading really cuts down series panel production drastically. The 12s string will be easiest to wire and will move power more efficiently at high voltage/low amps.

You may need to experiment to get the highest producing system. Its an interesting problem.
But maybe simplicity and ease of setup offsets that.