Questions for a future set up

[blrmaker]

Hello once again.



We are currently in the process of building a new home. I intend on using 2@18kpv hybrid inverters according to detail 4.5 in the latest manual. I have questions on the solar array set up that I initially conceived and am looking for advice if this would be my best rout or if y’all have better ideas.



First off my main array will be approximately 250’ away facing due south on a 6:12 pitch roof which should be close to the optimal year round angle of 28 degrees at my location according to footprint hero. I plan on using 48 Silfab SIL-380 HC panels in a 12 panel string x2 paralleled into 1 per 18kpv in the first MPPT for a max of 506.04Voc and 22.72Isc. The problem with this location is that it will get shaded by the pine forest after 5 pm. I plan on using 8ga THWN wire to run underground through 1 ½” buried conduit from the array structure/junction box to the MPPT for each string and 10ga THWN wire for the ground (250’ total run).




Second array will be 24 of the same Silfab panels in a 12 panel string for each 18kpv on the #2 MPPT 506.04Voc and 11.36Isc. The problem with this location is pointing approximately at 244 degrees and is on a 12:12 pitch roof (45 degrees) however there will be no shading until sunset.



The 3rd array will be 20 Hyperion HY-DH108P8 400W(B) bifacial panels in 1 string of 10 to the 3rd MPPT on each inverter: 370.7Voc and 13.79Isc. This array will be on a south facing pergola over a patio by the pool with a 6:12 pitch (26 degree). This array will see no shading.




So one question is on the first array, is it worth running the 2@12 panel strings in parallel into one of the 2 available MPPT inputs on MPPT 1? This will save a running a second set of wires over the 250’. I believe the math works out according to the 18kpv spec sheet for being under voltage and amperage.



Next question is the 2nd array of 26 Silfab panels. This array would be on top of my garage which is a nice flat roof but with a bad roof pitch for optimal angle and pointing southwest at 244 degrees from north. This array will also be the closest to the inverters. Question is, is it worth installing on top of the garage being it is sub optimal?



3rd question on array 3 with the bifacial panels. Do you think there will be much bifacial gain being 8’ up and close to a pool and the surrounding light-colored concrete?



Finally, does my math seem ok for the ratings on the 18kpv?

For reference the land lay out.

Thank you all for your input!

 

[DIYrich]

First off my main array will be approximately 250’ away.
48 Silfab SIL-380 HC panels in a 12 panel string x2 paralleled into 1 per 18kpv in the first MPPT for a max of 506.04Voc and 22.72Isc. I plan on using 8ga THWN wire to run underground through 1 ½” buried conduit from the array structure/junction box to the MPPT for each string and 10ga THWN wire for the ground (250’ total run).

So one question is on the first array, is it worth running the 2@12 panel strings in parallel into one of the 2 available MPPT inputs on MPPT 1? This will save a running a second set of wires over the 250’. I believe the math works out according to the 18kpv spec sheet for being under voltage and amperage.

8awg is good for 40 amps, so is way oversized for 22.72 a. Cuts down on losses, so should work. MPPT1 has two connections. If you run 2 sets of 10awg wire, then if one line goes bad, you have the other. 10AWG can handle 30 amps, so one line could handle both strings if one line has problems. Two 10 AWG lines allows you to move one to another MPPT if MPPT1 is having problems.

Better yet, run two 8 AWG lines. 250ft is a long stretch if there is a problem with a line, or if you want to upgrade.

 

[DIYrich]

Next question is the 2nd array of 26 Silfab panels. This array would be on top of my garage which is a nice flat roof but with a bad roof pitch for optimal angle and pointing southwest at 244 degrees from north. This array will also be the closest to the inverters. Question is, is it worth installing on top of the garage being it is sub optimal?

Use PV watts to estimate production.

3rd question on array 3 with the bifacial panels. Do you think there will be much bifacial gain being 8’ up and close to a pool and the surrounding light-colored concrete?

For the small additional cost of bi-facial, looks like you are a good candidate to get the 10+% additional gain.

 

[blrmaker]

Use PV watts to estimate production.



For the small additional cost of bi-facial, looks like you are a good candidate to get the 10+% additional gain.

Thank you for the responses. I am working on the PV watts and trying to figure out what it is telling me. lol

 

[blrmaker]

Follow up question. At the ground location of the first array I plan on installing an outdoor enclosure with either dc disconnect or dc breakers to shut down dc in case of maintenance or emergency. Which would be preferred?