16kw DC Solar with Sol-ark 15k

[ruralsolar]

I have a few other posts but I think I'm narrowed down to what I need to finally go to the bank and get my funding! I'm looking for a ~16kw DC power solar system linked to a sol-ark 15k.

• Quantity 36 ~450W panels - what panels exactly will depend on what is available when I'm able to actually purchase them. Leaning towards bi-facial but only if price is right
• Quantity 1 Sol-Ark 15k. Will do battery "later" as NYSEG is one for one with net metering so battery is only needed for when grid is down.
• Sinclair Designs Season Adjustable 36 Panel - Maybe "overkill" to do season adjust but I'd rather have the option than wish I had it later.
• Sub-Panel for "before" sol-ark to take high amperage/draw loads. Grid --> electric meter panel --> High Loads Panel --> Sol-ark --> "Main" house panel
• Quantity 2 IMO Disconnects to be mounted at the racking. Assuming 4 Series of strings combined to 2 parallel strings (9 panels on series, 18 on parallel). Should keep me below the 500V DC VOC and below the 26amp rating per MPPT on the sol-ark while leaving me with one more MPPT for potential future addition.
• Array will be ~150-175ft wire run from where sol-ark will be located in basement of home
• Located in upstate NY, NREL PVWatts says I should get ~19,000 KWH per year at 32.5 degrees, so if I do my diligence of seasonal adjust that should go up marginally
• Permit plans and schematics from a reputable and previously mentioned firm on this site (Have a few on the list so far)

My brain says I'm missing something but I'm not sure what. If anything my only question that my local electrician could answer is the appropriate sub-panel to use to before the sol-ark? The core reason I'm doing the reverse of a critical loads panel is the number of low draw circuits in the current "main" panel are so numerous it makes no sense to move them to a different panel, it'll be easier to move the ~5 circuits instead (all 240V). Thoughts?

 

[ruralsolar]

Adding in for additional info from my Emporia Vue monitor that's been going for a little over a month, this info is peak KW demand. These would be circuits to add to the "high load panel", to expand some, the heat pump I can put the 3kw backup heater on it's own circuit separate from the heat pump itself which I would end up leaving on the main house panel backed up by the sol-ark BUT would be setup where if power goes out it'll safely ramp down to "off".

• Oven - 3.02
• Heat Pump - 8.01 - This has a 3kw backup heater for when doing a defrost cycle and/or when the outside temp is so cold that heat pump along can't keep up
• Dryer - 5.95
• HotTub - 5.68
• Hot Water Tank - 3.75
• Dishwasher - .926

 

[DIYrich]

With a 16kw system, if they are all producing at the same time, it may max out the Sol-ark. You might want to face some panels slightly to the east, and some to the west. Get longer production at a lower level (same total daily production). Or, move a few kW to micro inverters and connect as AC into the Gen port.

 

[rhino]

Sinclair Designs Season Adjustable 36 Panel - Maybe "overkill" to do season adjust but I'd rather have the option than wish I had it later.

The season adjust will be beneficial to you. Since you are in New York you will be able to adjust it down to 60° for winter which will make a big difference and help shed snow. The "fixed tilt" version can only go to 35° tilt. You can also ask to have the two rows separated by a certain amount like 6". That way when the top row of panels is shedding snow it won't cover the bottom row. Would also be beneficial if you get bifacials since you'd have sunlight able to shine between the rows to reflect off of snow.

 

[Danke]

You have 3 MPPTs with the 15K

So 6S2P per MPPT with give you 36 total. 9 in series is too much.

Solar Panel Sizing 4.5

www.sol-ark.com

 

[ruralsolar]

With a 16kw system, if they are all producing at the same time, it may max out the Sol-ark. You might want to face some panels slightly to the east, and some to the west. Get longer production at a lower level (same total daily production). Or, move a few kW to micro inverters and connect as AC into the Gen port.

I shouldn't since the Sol-Ark can do 19.5kw in PV, not going with battery right now so anything over the 15kw output to my main panel will be exported which is fine. If clipping was to be expected with the design that's a good idea!

The season adjust will be beneficial to you. Since you are in New York you will be able to adjust it down to 60° for winter which will make a big difference and help shed snow. The "fixed tilt" version can only go to 35° tilt. You can also ask to have the two rows separated by a certain amount like 6". That way when the top row of panels is shedding snow it won't cover the bottom row. Would also be beneficial if you get bifacials since you'd have sunlight able to shine between the rows to reflect off of snow.

The slight cost increase I agree will be worth it in the end. It is the route I'm going, as for bifacials might not be going that way though.

You have 3 MPPTs with the 15K

So 6S2P per MPPT with give you 36 total. 9 in series is too much.

Solar Panel Sizing 4.5

www.sol-ark.com

Hmmm, haven't done the math fully, I'm working with a DIY friendly company so they'll steer me in the right direction

 

[Danke]

I shouldn't since the Sol-Ark can do 19.5kw in PV, not going with battery right now so anything over the 15kw output to my main panel will be exported which is fine. If clipping was to be expected with the design that's a good idea!

The slight cost increase I agree will be worth it in the end. It is the route I'm going, as for bifacials might not be going that way though.

Hmmm, haven't done the math fully, I'm working with a DIY friendly company so they'll steer me in the right direction

Is that “DIY friendly company” the one that advised you to put 9 in series? 9S2P per MPPT

 

[Solar Guppy]

I have a few other posts but I think I'm narrowed down to what I need to finally go to the bank and get my funding!

At today consumer interest rates, the payback is never for solar, so I am curious what is your reasoning for this? You won't have batteries, so this is just one big gridtie system?

 

[ruralsolar]

Is that “DIY friendly company” the one that advised you to put 9 in series? 9S2P per MPPT

Nope, that was me doing rough uneducated math

 

[ruralsolar]

At today consumer interest rates, the payback is never for solar, so I am curious what is your reasoning for this? You won't have batteries, so this is just one big gridtie system?

Rough estimates say I'll have 6-7 year ROI with assumptions of electric costs increasing at least 3% year over year, this does take into account federal and state tax credits, without those the ROI would be longer, possibly to the point of "why bother" from a strictly financial perspective. Right now it is one big grid tie system, my utility is still 1:1 per kwh with a once a year true-up for excess solar generation. The only reason I'll do battery later is for "grid down" situations.

 

[Ampster]

9 in series is too much.

I did not see the voltage on those panels. How did you reach that conclusion?

Nope, that was me doing rough uneducated math

If you are in New York you should account for higher voltage at lower temps as well.

 

[ruralsolar]

I did not see the voltage on those panels. How did you reach that conclusion?

If you are in New York you should account for higher voltage at lower temps as well.

I don't know what panel I'm getting at this point but they will be sized to meet my desired minimum 16kw.

Right!? Part of my discovery and learning, makes sense but also something I did not know would have to be thought about.

 

[Danke]

I did not see the voltage on those panels. How did you reach that conclusion?

450W x 18 per MPPT.

 

[Solar Guppy]

Rough estimates say I'll have 6-7 year ROI with assumptions of electric costs increasing at least 3% year over year, this does take into account federal and state tax credits, without those the ROI would be longer, possibly to the point of "why bother" from a strictly financial perspective. Right now it is one big grid tie system, my utility is still 1:1 per kwh with a once a year true-up for excess solar generation. The only reason I'll do battery later is for "grid down" situations.

Is that with interest rates included, which for consumer rates are 9% plus?

Make a spreadsheet, cost out everything ( shipping, conduits, concrete ect ) including loan costs before you pull the trigger. Also most residential tiers limit to 10kwh net metered systems, above that gets into all sorts of issues, like mandatory insurance, TOU rates ect.

 

[ruralsolar]

Is that with interest rates included, which for consumer rates are 9% plus?

Make a spreadsheet, cost out everything ( shipping, conduits, concrete ect ) including loan costs before you pull the trigger. Also most residential tiers limit to 10kwh net metered systems, above that gets into all sorts of issues, like mandatory insurance, TOU rates ect.

This guy made one already, fine it doesn't take into account interest charges, I'll concede that: https://docs.google.com/spreadsheets/d/14adTRsoK_6cY6lLonZz6q27T2ZnmWHg5mtCzkDAme68/edit#gid=0

My interest rate is 6.99%, it's a 10 year loan but once the system is online, the money I would have paid my utility will go to the loan to pay it off faster avoiding interest, then when I get tax refund for 2023 I can apply that to the loan.

I assume you meant "kw" now "kwh" for size, not an issue in NYS below 50kw, above that there is another process you have to go through. We do not have TOU (yet). There really are not any "gotchas" for my utility other than having to pay the basic service charge of ~$17 today to remain connected to the grid.

 

[Solar Guppy]

Keep in mind the tax credit is non-refundable, which means if your actual tax liability is less than the credit, the difference is carried forward and its value falls with inflation until it is used up in future years.

 

[Nobodybusiness]

tax refund

Tax credit not refund.

 

[Solar Guppy]

This guy made one already, fine it doesn't take into account interest charges, I'll concede that: https://docs.google.com/spreadsheets/d/14adTRsoK_6cY6lLonZz6q27T2ZnmWHg5mtCzkDAme68/edit#gid=0

I doubt that would mean it is your costs, for example, your looking at about 10K for having a ground mount array ( vs roof mounted ) based on your number of panels and the msrp of the racking you mentioned the manufacture. ( Add in concrete and other materials to dig, mix, pour, brace and shipping )

Then there is distance, further away, costs go up fast, you need trenching, conduit, wire which is expensive.

My point is not that I am suggesting you are wrong, it's that you do not have your own spreadsheet of costs for your proposed system, so you really don't know. In any solar system, it starts with full plans and bill of materials and labor and quotes on all parts, as every installation is unique.

Getting the money and permits are the last step in the process, from what you have wrote you need a costed BOM.

 

[Quattrohead]

Personally I would ditch the adjustable tilt for the panels and put that towards a battery, you will love it when the solark switches over the battery during a power outage. You will feel like a king in the hood LOL

 

[DIYrich]

I shouldn't since the Sol-Ark can do 19.5kw in PV, not going with battery right now so anything over the 15kw output to my main panel will be exported which is fine.

No quite. 19kW DC PV can be changed connected, but there is a max of 15kW delivered to battery and ac. Anything above that is wasted. There are also threads talking about problems getting over 13kW with DC solar. If panels are oriented so that max 13kW at any one time, then that is fine. Otherwise, I recommend anything over 13kW be ac connected PV.