Advice: Final Configuration Before Install

[keaton85]

I am just about to mount my panels on my 12/12 pitch roof and wanted to see if anyone sees any issues with this system:

Inverter: Growatt 10KW
Max PV voltage: 600V
Full load range: 210-500V
MPPT inputs: 4X

Panels: 31X Solarever 410W
Vmp: 31.35V
Imp: 13.08A
Voc: 37.12

Strings:
1: 6X on outbuilding
2: 13X on roof
3: 12X on roof
4: Last MPPT for possible expansion

The 13X panels is where it gets a little high in voltage. By using most of the calculators I come with about 560V at -25F which is pretty low for Midcoast Maine.

If I were to break the strings down into 8X, 8X and 9X strings it would add more complexity on the roof and another #12 cable run back down to the inverter. benefits? There is some shading in the morning and afternoon but its not enough to make a massive difference.

 

[sunshine_eggo]

You are over-paneled at 12.7kW vs. 10kW MPPT.

Otherwise, I see no issues with your proposed config.

 

[keaton85]

You are over-paneled at 12.7kW vs. 10kW MPPT.

Otherwise, I see no issues with your proposed config.

Max PV paneling 20kw

 

[keaton85]

bump, anyone have any insight on overpaneling? Spec sheet states up to 20kw array. Am I missing something?

 

[sunshine_eggo]

bump, anyone have any insight on overpaneling? Spec sheet states up to 20kw array. Am I missing something?

Over-paneling is simply putting more PV on a controller than it can output. Since you haven't provided a model number or link to datasheet, I presumed 10kW was a potential limit to the PV. If it says 20kW PV, then either that's an over-paneling limit or a max output.

 

[keaton85]

Over-paneling is simply putting more PV on a controller than it can output. Since you haven't provided a model number or link to datasheet, I presumed 10kW was a potential limit to the PV. If it says 20kW PV, then either that's an over-paneling limit or a max output.

Thanks Sunshine for responding.

Here is the data sheet:

https://signaturesolar.com/content/documents/GROWATT/MIN_8200-11400TL-XH-US_Datasheet_EN_202402.pdf

The primary panels are on the roof so 10kw will be the main array. The other panels are in a more shaded area since I used them for a roof on a wood shed. It was almost the same cost to buy a pallet over just the 25 panels for the roof.

The other “spare” input would be to tie in a small array in a west facing orientation if I even bother. I don’t use much power, the large array is to prep for charging electric vehicles in a few years.

 

[sunshine_eggo]

Okay. The PV output of the MPPT is notably higher than 10kW

360V nominal
13.5A max

13.5A * 360V = 4860W per MPPT, so 4X MPPT 20kW

You wouldn't be over-paneled @ 12.7kW

 

[keaton85]

So is it better to break the roof into three strings over two? Which wouldn’t leave me with a spare yet realistically it probably won’t be used.

 

[sunshine_eggo]

It seems to

So is it better to break the roof into three strings over two? Which wouldn’t leave me with a spare yet realistically it probably won’t be used.

I used nominal PV voltage value to estimate MPPT output. I can't give you a definitive answer. The 13S string will be very slightly over-paneled exceeding 5000W for the MPPT. I would not expect this to be a problem.