I am looking at installing 26 Hanwha L-G4.2 330 Watt cells on a ground mount system. Right now it looks like I will probably use the Unirac GFT in a 2 x 13 configuration (portrait panel layout). Also looked at going with an Iron ridge system but the Unirac is edging ahead. I plan on using the SMA Sunny Boy 7.7 US-40 with 11 panels to input A, 11 panels to input B and 4 panels to input C. My utility does net metering and will roll any excess generation over to the next month. When the net metering contract is terminated you forfeit all credits to the utility. I would like some input on the infrastructure I would need.
My house is on the northwest side of the property and I have a large field to the south of my property that I plan to have the array face 15 ft or so off the property line. There should be no issues with shading besides really early in the morning and towards sunset. I have 2 barns that I call the North and South barn. The house is farthest north then North Barn then the South barn. The house and South barn have 200 amp service. I asked the utility if I could hook the solar into the south barn and get the credits on the house meter as the rack would just be 50 feet southeast of the South barn. They of course won't let me do that even though the two meters/bills go to the same address. The house averages about 1000 kWh a month for the last 3 years. ~600 kWh or so in the spring or fall and usually > 1500 kWh in Jan and Feb since I heat with geo thermal. The panels for my area should put out a little over 12,000 kWh a year.
What I plan on doing is putting a new 100 amp sub-panel in the north barn that goes to the house 200 amp main panel. That distance is close to 150 ft. 120 ft in 1 1/2 pvc conduit from the corner of the barn to basement wall of the house then another 20 ft or so to the panel. I would use a 100 amp breaker at the main panel and 3 Al #1 XHHW-2 with a Cu #4 THWN-2 ground. The Sunny Boy would be mounted on the opposite corner of the barn from the sub panel inside as that is the direction of the racks. There would be a 40 amp circuit breaker in the subpanel and it would supply ~ 85 ft (probably less) of #6 Cu THHN-2 in 3/4" conduit inside the barn to the inverter. I assume I would use a #8 neutral and #8 ground. From the inverter out to the rack is another 160 ft so I would need 3 paired DC lines of #10 for the 3 strings in 1" pvc conduit plus a #10 ground.
In the Sunny Web program that brings my total relative power loss to 2.3%. It might be a little less than that because I was pretty conservative on the distances between the runs. Sunny web projects 12,455.20 kWh of yield per year. PVWatts has it at 11,908 kWh. Still putting the system together but I do have the panels. One thing I noticed since reading these forums is it looks like I probably need to get a load center rated at 125 amps and put a 100 amp main breaker in for a 40 amp backfeed breaker for the north barn. The 40 amp backfeed should be okay at the 200 amp panel unless I am missing something.
Any other suggestions as I am sure I am missing stuff? To me this seemed like the most logical way but I am also new to this stuff. Open to any suggestions if you see a better way.
My house is on the northwest side of the property and I have a large field to the south of my property that I plan to have the array face 15 ft or so off the property line. There should be no issues with shading besides really early in the morning and towards sunset. I have 2 barns that I call the North and South barn. The house is farthest north then North Barn then the South barn. The house and South barn have 200 amp service. I asked the utility if I could hook the solar into the south barn and get the credits on the house meter as the rack would just be 50 feet southeast of the South barn. They of course won't let me do that even though the two meters/bills go to the same address. The house averages about 1000 kWh a month for the last 3 years. ~600 kWh or so in the spring or fall and usually > 1500 kWh in Jan and Feb since I heat with geo thermal. The panels for my area should put out a little over 12,000 kWh a year.
What I plan on doing is putting a new 100 amp sub-panel in the north barn that goes to the house 200 amp main panel. That distance is close to 150 ft. 120 ft in 1 1/2 pvc conduit from the corner of the barn to basement wall of the house then another 20 ft or so to the panel. I would use a 100 amp breaker at the main panel and 3 Al #1 XHHW-2 with a Cu #4 THWN-2 ground. The Sunny Boy would be mounted on the opposite corner of the barn from the sub panel inside as that is the direction of the racks. There would be a 40 amp circuit breaker in the subpanel and it would supply ~ 85 ft (probably less) of #6 Cu THHN-2 in 3/4" conduit inside the barn to the inverter. I assume I would use a #8 neutral and #8 ground. From the inverter out to the rack is another 160 ft so I would need 3 paired DC lines of #10 for the 3 strings in 1" pvc conduit plus a #10 ground.
In the Sunny Web program that brings my total relative power loss to 2.3%. It might be a little less than that because I was pretty conservative on the distances between the runs. Sunny web projects 12,455.20 kWh of yield per year. PVWatts has it at 11,908 kWh. Still putting the system together but I do have the panels. One thing I noticed since reading these forums is it looks like I probably need to get a load center rated at 125 amps and put a 100 amp main breaker in for a 40 amp backfeed breaker for the north barn. The 40 amp backfeed should be okay at the 200 amp panel unless I am missing something.
Any other suggestions as I am sure I am missing stuff? To me this seemed like the most logical way but I am also new to this stuff. Open to any suggestions if you see a better way.
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