Your Thoughts on my New Array Design

Turkey Hollow Solar

New Member
Joined
Oct 20, 2021
Messages
8
Location
Northern Vermont
Hi Solar Fans,

This is my first posting here, but I have been an eager consumer of content here for some time, especially Will's videos.

We're Going Solar!

I'm working on a system design and component selection for a new 10kW Ground-Mount, Net-Metered AC array for our residential property in Northern Vermont.

Plan is a combination of DIY for much of it, with final installation by a local solar installer. I'm hoping to do enough DIY to enable a 1/2 day job by a contractor.

Our utility is allowing us up to 15kW with just basic requirements. Beyond that they paperwork gets a lot deeper. So I'm planning for an initial 10kW, with plans/accommodations for another 5kW in the future. I can permit it initially for 15kW and only install 10kW for now, with no need to reapply for the 5kW upgrade.

Site is a mostly flat, open hay field with thick, heavy clay soil with minimal rocks and no ledge. No shade issues, and plenty of room for expansion. Wind can get pretty stong here, but we don't usually get hurricanes or tornados. Ground is covered with snow much of the winter, with the biggest storms being 24-36".

Grid connection is inside the residence, about 150' from the array. Plan to connect to main power panel, which has ~250' of 4/0 Aluminum service conductors back to the transformer. Plan is to ditch-witch the solar wiring into the home, and install required safety equipment in heated basement with a required disconnect outside.

Here's the basic system we're considering:

- Qty=28 72-cell Bifacial Panels, Adani ASB-7-AAA
Good deal available on these...~$145/ea new from dealer. Price is about $4000 plus wiring.
The rationale for bifacial panels is that they are apparently better at capturing reflectance from snow in the winter, especially in an open field.
Does anyone have experience with these panels? They are made in India. They claim to be a Tier 1 panel.

- Nuance Osprey PowerPlatform ground mount racking system, Two 2x7 rack segments for 28 panels/10kW total.
We like this option for the easier ground anchors. Price is about $5000 total for two racks and hardware. Distributor rents installation tool and pull tester for anchors.
It seems like an easy DIY assembly/installation, and doesn't require a contractor to drive ground screws.
Does anyone have experience with this system and its unique ground anchors?

- Inverters: Debating two options: Dual string inverters, or Enphase Microinverters

Enphase Microinverter option: IQ7Plus-72-2-US. Price is about $160 each, so $4480 plus wiring from a local distributor.
String Inverter Option: SMA Sunny Boy SB5.0-1SP-US-41. Price is about $1250 each, so $2500 plus wiring from a local distributor.
I'm a data junkie for work...so I like the per-panel data collection of the Enphase units. But is that worth another $2000? I'm not sure...
I'm guessing this comparison has been debated here before...can anyone suggest a thread? Or if not, I'd appreciate help with pros/cons, etc.

Thanks in advance for all your feedback...I really appreciate it!
 

SteinVT

New Member
Joined
Jul 30, 2021
Messages
29
Location
Vermont
Hi just found your post. I just finished almost exactly the same system.

I had a similar situation, heavy clay except with rocks, open field about 200' from the house. I'm in Vermont, so plenty of snow. I went with the Adani 365w bi-facial and Enphase micro inverters. No good reason for the micro inverters except I like the redundancy and it's cool to monitor the individual panels. I ended up doing all of the work myself, with help from my wife. I added the Enphase Envoy to monitor output and house load, and in the last 3 weeks, we are about 100kwh in the black. Very happy with the setup.

Here is a link to my thread.

Good luck, you'll do fine. - Mark
 

DThames

Photon Sorcerer
Joined
Nov 22, 2019
Messages
1,736
You might consider that if someday you want standby emergency power, what will you need to leverage your existing setup. That might point you toward the string array.
 

Jim Lee

Solar Enthusiast
Joined
Nov 5, 2021
Messages
65
Apparently, with Emphase inverters your going grid tied with a net-meter. you should look into using an off grid converter that is grid tied and zero feed back to utility. No utility paperwork and in some cases, no permits and the power doesn't go out when the utility is down. Check out Signature solar and David Poz you-tube videos.
 

Turkey Hollow Solar

New Member
Joined
Oct 20, 2021
Messages
8
Location
Northern Vermont
Thanks everyone for all the feedback! I lost track of this thread over the holidays...sorry about that.

SteinVT...I didn't mention it in my profile...but I am also a Vermonter. We're up in the Islands. It looks like you must have sourced the materials from CED in Burlington? I actually bought the remainder of the Adani panels...53 of them...I couldn't pass up that deal, so we're going a bit bigger than originally planned.

The Adani performance has been outstanding so far. My son and I have been testing them with the front face covered with cardboard, and have pulled 50watts from the backside only (with snow on the ground). I originally spec'ed 300W APSystems microinverters and bought a two-channel unit to get started, but even here in winter they are clipping most of the day. So I'm upgrading to a 375W unit that I think will be a better match.

I like the simplicity of the Sunmodo ground mount you used...I looked at a few options, and theirs is the simplest, cleanest looking installation. We ended up getting a great deal on the Nuance system, so that's what we will be using. Its not as clean as the Sunmodo, but the price made it a no brainer.

We are doing a vanilla grid-tie to get started. The net metering registration in Vermont is basically automatic, and the utility has been very helpful getting us started (and letting me know I need to upgrade the transformer on the pole). We might add an AC-coupled battery system later, but for now the microinverters should suit us well. I like the Sol-Ark system I see often on the Engineer775 channel...that would be a great system for a battery backup and better grid-feed management in the future. It can be directly coupled to the AC from the microinverters...so no need for DC runs, although this might be slightly more efficient.

Thanks everyone for the feedback....I'll post some updates soon!
 

SteinVT

New Member
Joined
Jul 30, 2021
Messages
29
Location
Vermont
The guys at CED-Greentech were great to work with. Wow, 52 panels, that is a big array, almost 19kw. How are you guys planning to use all that power? My neighbor has 7.6kw and hasn't paid for power in three years. As a matter of fact he gives the power company about $300 a year in free power.

The Adani panels seem to work well. Performance wise, October was great. The meter ran backwards. Since then not so much. There have been a couple of days the panels were covered with an inch of snow and we still made some power. Not a lot but some. One very clear night with a full moon were actually were making power by moonlight. Basically winter at this latitude with the cloud cover, low angles and short days is tough. Come spring, we should have more power than what we know what to do with. - Mark
 

Turkey Hollow Solar

New Member
Joined
Oct 20, 2021
Messages
8
Location
Northern Vermont
Yes....I'd recommend CED Greentech to anyone reading this thread. Their prices were very competitive, and any cost difference is easily justified by the superb local customer service. Great resource, and I found them to be happy to help out the DIY'ers.

That's a lot of panels for sure, but actually I'm sizing the electrical conductors to handle about 35kW all together. We plan to add a pole barn in a year or two to add another 10kW+ as rooftop solar. We need to upgrade our transformer either way.

For excess power, I've spoken with a couple local businesses that are interested in bartering with the power credits. Its very helpful how VT Electric Coop structures the Group Net Metering program. They make it easy to exchange credits between customers, so I can transfer credits to virtually any business or residence in their service area. They even have a charitable contribution program where I can make donations of excess power, and they administer the whole thing.

But actually, I'm not sure I'll even have any leftover. My son wants to start crypto mining with it, so that could use it all up in itself...and he's surprised me with how good the business case is for doing that. I like the idea that its green mining with zero fossil fuel...and it helps the solar ROI greatly.

Great to hear that you are getting moon solar! That's really impressive! I think the bifacial configuration really works...we've found the panels to produce up near their rating, even on the winter solstice. And at <$140/panel, that deal can't be beat even by the best online supplier.

Thanks for reaching out...its nice to share experience with fellow Vermonters!
 

SteinVT

New Member
Joined
Jul 30, 2021
Messages
29
Location
Vermont
That was a great deal. I think I paid more like $180. I hope you continue to post to this thread as you go through the design process. I found threads like this very valuable as I was designing mine. You must be using some monster conductors.

I am also curious about the details. We should keep in touch. When spring rolls around, I would love to take a quick motorcycle ride to the islands to see your project and your are welcome anytime to see mine. - Mark
 
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