Sol-Ark 15k and panel wiring

[Ben2022]

I think I done messed up….
( Note: I can’t physically put anything together until after my building inspection)

I’m buying and laying out everything for an upcoming install. Got the Sol-Ark 15k, got the Iron Ridge mounting, the panels I was going to buy went away (out of stock forever).

I came across some JA 535W Panels for less than $200 per panel. I panicked and bought 20 (the max I have space to mount). Now they are on their way and I remember I should work out wiring….

Per Sol Ark online string calculator I can handle 9 MAX on input 1, and 9 MAX on input 2. I CANNOT handle only 2 on input 3- I assume due to minimal voltage.

Question 1: So shit now what? Any way I can make these extra two work?

Question 2: my rows are 5 panels each which is going to make wiring awkward with 9 panels. Any suggestions to help? Branch connectors? I’m going to be using an iron ridge jay box- maybe combine them in there and just eat the cost on extra wire?

Got a great deal on panels (I think) but caused other issues.

Thanks

 

[Ben2022]

Never mind on question 1 - I’m an idiot I was focusing only on maxing out each MPPT not thinking I could split it differently.
I guess I can do 7,7 and 6 on the MPPT ??‍

 

[Nobodybusiness]

Per Sol Ark online string calculator I can handle 9 MAX on input 1, and 9 MAX on input 2. I CANNOT handle only 2 on input 3- I assume due to minimal voltage.

Buy 7 more, use microinverters to AC couple or use as spares.

 

[BentleyJ]

I was just going to suggest that as your second post came in.

 

[Ben2022]

I was just going to suggest that as your second post came in.

Sometimes I get focused on - MAX


Any suggestions on wiring/routing? Branch connectors or just a shit ton of wiring?

 

[pvgirl]

Sometimes I get focused on - MAX


Any suggestions on wiring/routing? Branch connectors or just a shit ton of wiring?

You don't need or want branch connectors, as all your strings are in series, one panel plugged in to the next up to the length of the string, 6 or 7, run a wire from each end of each string to the inverter(plus a ground). Depending on how your panels are laid out you may need extension wires to work around obstacles, etc.

 

[BentleyJ]

Its only 3 series strings, 1 for each MPPT input. I wouldn't consider that excessive. 7, 7, 6.
The OP says 5 panels per row but no detail if the rows are all together.

The most obvious way is to start at one corner and either go across or up/down then jump to the next adjacent row. That does not take into account shading. Is that an issue for your set up?
If so, the panels with similar conditions should be grouped together and wired accordingly. Consider optimizers for strings with shade.

A diagram of the layout would help

 

[Ben2022]

Its only 3 series strings, 1 for each MPPT input. I wouldn't consider that excessive. 7, 7, 6.
The OP says 5 panels per row but no detail if the rows are all together.

The most obvious way is to start at one corner and either go across or up/down then jump to the next adjacent row. That does not take into account shading. Is that an issue for your set up?
If so, the panels with similar conditions should be grouped together and wired accordingly. Consider optimizers for strings with shade.

A diagram of the layout would help

5 per row 4 rows all packed together in a block.

Shading isn’t an issue at all. I was just thinking how awkward it would be and possibly excess wire usage having to do one full row +2 of the next row then run all the way back to the Jay box. Then 3 of the second row all 5 of the 3 row.

I guess if I did 7-8-5 at least one of the rows with me only the 5 and would be “neat” wiring.

With the wire being a little costly I want to efficient with my runs.

If the rails run horizontal the wires have to also correct?

 

[BentleyJ]

Seems like you are considering wiring neatness as the project priority rather than optimum solar layout. Not saying the wiring should just be left loose laying randomly under the panels but it should be considered AFTER the wiring scheme is figured based on the 7, 7, 6 plan and then connecting them with the least footage of wire between the array and the J box (Do you need a J-Box? 3 strings connecting to 3 MPPT inputs). The wire does not have to follow the horizontal rails, it could run vertical but then they may need additional support so as not to have droop in between rails.

 

[Ben2022]

Seems like you are considering wiring neatness as the project priority rather than optimum solar layout. Not saying the wiring should just be left loose laying randomly under the panels but it should be considered AFTER the wiring scheme is figured based on the 7, 7, 6 plan and then connecting them with the least footage of wire between the array and the J box (Do you need a J-Box? 3 strings connecting to 3 MPPT inputs). The wire does not have to follow the horizontal rails, it could run vertical but then they may need additional support so as not to have droop in between rails.

I can’t lay out the panels any differently (physically) but I have a bad habit of running wires whatever way is “easy” and not always the most efficiently. However with the amount of wire I’m going to need here, I feel like I need to be efficient for cost purposes.

The contractor building the shop is putting in two jay boxes for me anyway with conduit down into the building. I figured this one might as well be the iron ridge solar one. The conduit is going to drop into a wire trough that will connect to the Sol Ark.

(The other box is for radio antenna wire)

So just wire clips under the panels and conduit from the panels to the jay box?

 

[BentleyJ]

Yes

 

[Ben2022]

Yes

So I realized after I drew this I didn’t run the wire down the rail but in real life I will. I think this is the best layout.


Thoughts?

 

[pvgirl]

So I realized after I drew this I didn’t run the wire down the rail but in real life I will. I think this is the best layout.


Thoughts?

Only 4 panels in series will not be enough voltage to reach the 175volts minimum needed by the sol-ark.

 

[Ben2022]

Only 4 panels in series will not be enough voltage to reach the 175volts minimum needed by the sol-ark.

Sol-Ark string calculator site shows it will work with these panels. Voc for 4 = 197.8 Voc min for 4 = 186.92

I thought the min for the Sol Ark was 150?

 

[pvgirl]

For operating range we want to use Vmp not Voc best case Vmp is going to be 166 volts, spec sheet lists nominal voltage range as 175-425volts. In real world conditions voltages will often be less and there's not much margin over the minimum startup voltage of 125.

 

[Ben2022]

For operating range we want to use Vmp not Voc best case Vmp is going to be 166 volts, spec sheet lists nominal voltage range as 175-425volts. In real world conditions voltages will often be less and there's not much margin over the minimum startup voltage of 125.

Well I can go back to the plan of 7-7-6 strings but the wiring is a bit more awkward when I drew it out. I only went this route because of the calculator (see below) from Sol-Ark. Ok back to the drawing board.

Edit: clicked the wrong pic for upload.

 

[Balrog006]

Well I can go back to the plan of 7-7-6 strings but the wiring is a bit more awkward when I drew it out. I only went this route because of the calculator (see below) from Sol-Ark. Ok back to the drawing board.

Edit: clicked the wrong pic for upload.

You’re much better off from a minimum voltage startup standpoint and a voltage drop/distance standpoint with the 7-7-6 configuration.