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diy solar

Insane quotes for ground mount

diygm

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I have three quotes for three different solar installers with good reputations in my area. All are pretty outrageous, all came in at $40k for ~12kw, All said the issue was that I want a ground mount. 32 panels.

Quote 1 was $8400 extra for the ground mount.
Quote 2 was $8700 extra for the ground mount.
Quote 3 was $9000 extra for the ground mount.

You have to be kidding me. I live in a county with zero permitting or inspections required for a ground mount. I have a spot 95 feet from the breaker box that has 100% unobstructed southern exposure 365 days per year. There is absolutely nothing between where the panels would go, and the breaker box, so the trenching is no problem. The one issue with this area is that we do get high winds, it is not theoretical, we *will* get 80-100MPH gusts out of the northwest at least once per year. This is Colorado.

I have decided to go DIY for the entire project.

I looked at some of the DIY racking people have shown on here and a lot of them clearly aren't going to hold up to 100MPH.

Has anyone done a DIY install that has held up to these kinds of winds, and what did you use?
 
I have three quotes for three different solar installers with good reputations in my area. All are pretty outrageous, all came in at $40k for ~12kw, All said the issue was that I want a ground mount. 32 panels.

Quote 1 was $8400 extra for the ground mount.
Quote 2 was $8700 extra for the ground mount.
Quote 3 was $9000 extra for the ground mount.

You have to be kidding me. I live in a county with zero permitting or inspections required for a ground mount. I have a spot 95 feet from the breaker box that has 100% unobstructed southern exposure 365 days per year. There is absolutely nothing between where the panels would go, and the breaker box, so the trenching is no problem. The one issue with this area is that we do get high winds, it is not theoretical, we *will* get 80-100MPH gusts out of the northwest at least once per year. This is Colorado.

I have decided to go DIY for the entire project.

I looked at some of the DIY racking people have shown on here and a lot of them clearly aren't going to hold up to 100MPH.

Has anyone done a DIY install that has held up to these kinds of winds, and what did you use?

Commercial mounting systems rated for high winds is expensive. At $/Watt at ~75% of the array wattage, it's actually not completely outrageous. I've seen racking systems that cost more than the panels.

Have you looked into DIY-ing already engineered systems?
 
I don't have a wind meter, so I can't tell you the speed my mounts have survived, but they did survive winds that have blown down a 18" Oak tree nearby. Does that give you anything? BTW, I'm now in the assembly stage of making my v5.0 mount, which will hold 6 grid-tie panels. It will look a lot like my v4.0 mount, pictured below. This mount cost me about 400$ in steel, plus a roll of welding wire, and my labor.
 

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Commercial mounting systems rated for high winds is expensive. At $/Watt at ~75% of the array wattage, it's actually not completely outrageous. I've seen racking systems that cost more than the panels.

Have you looked into DIY-ing already engineered systems?
Well, I did get a quote from one DIY company that suggested I use 2" galvanized pipe and just use augered ends on the vertical supports. I tossed that one.
 
I don't have a wind meter, so I can't tell you the speed my mounts have survived, but they did survive winds that have blown down a 18" Oak tree nearby. Does that give you anything? BTW, I'm now in the assembly stage of making my v5.0 mount, which will hold 6 grid-tie panels. It will look a lot like my v4.0 mount, pictured below. This mount cost me about 400$ in steel, plus a roll of welding wire, and my labor.
Interesting concept to leave an 18" gap between the panels. For my 32 panels, that would make the array much wider. Also, I see a building and trees near your panels that would break up the winds. In my case, imagine the array sitting on top of a hill in an huge empty pasture with no trees and the nearest building that would block the wind being about 300 feet to the NW.
 
I don't have a wind meter, so I can't tell you the speed my mounts have survived, but they did survive winds that have blown down a 18" Oak tree nearby. Does that give you anything? BTW, I'm now in the assembly stage of making my v5.0 mount, which will hold 6 grid-tie panels. It will look a lot like my v4.0 mount, pictured below. This mount cost me about 400$ in steel, plus a roll of welding wire, and my labor.
Why do you call them "grid-tie" panels".? I've seen you say this before. Aren't they just regular solar panels?
 
The gap was not intentional in the sense of a wind-gap. I was originally designing it for landscape oriented panels, but when I settled on 120VDC as my standard string voltage, I just put up 4 instead.

The new v5.0 design is going to have 6 in landscape instead of 4 in portrait. To give you a better sense of my earlier designs, here's some pics of my v1.4 single row design, which is my oldest, at 6 years.

In terms of your winds, I'd tell you that concrete is your friend. I used an 15" auger to dig my post-holes, with the steel pipe sunk 36" in concrete.
 

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Holes, concrete, stupid big galvanized angle iron, double strut. Watch craigslist. All diy-able. And some big dead man or duckbill anchors.
 
Why do you call them "grid-tie" panels".? I've seen you say this before. Aren't they just regular solar panels?
Yes, I know there's a lot of confusion about what "classes" panels pertain to. That moniker is to differenciate them from the 12V category, that is more oriented towards the automotive market. They are grid-ties to me because they are typical of the kinds of panels you will see up on people's roofs for grid-tie applications. Is there another more colloquial term now being used for larger 30-45V panels?
 
Ground mount systems, esp in high wind regions, require either a lot of concrete or a lot of excavation, or a combination of the two. For the DIY Unirac system I looked at, I would have had to drill 14 holes, 8' deep, 12" diameter and fill them with concrete. I'm 100+ miles from the nearest ready-mix plant, so either I'd pay a small fortune for a truck or two of concrete, or have to buy a couple of pallets of cement and spend countless hours feeding a mixer. And that assumes I could find anyone to bore the holes. Like most tractors, mine doesn't have down-force on the 3pt hitch, so a PTO driven auger doesn't work - you need either a drill rig or maybe a skidsteer with an auger on the front.

I ended up going with Osprey mounts which use duckbill anchors like Bluedog255 suggests above. The anchors are pull-tested during installation to verify holding strength.
 
Yes, I know there's a lot of confusion about what "classes" panels pertain to. That moniker is to differenciate them from the 12V category, that is more oriented towards the automotive market. They are grid-ties to me because they are typical of the kinds of panels you will see up on people's roofs for grid-tie applications. Is there another more colloquial term now being used for larger 30-45V panels?
Just regular solar panels. Could call them residential or commercial, I guess. Or maybe framed panels. But grid-tie is confusing, because that's only one way they can be used.
I was also curious if there was something special about them, that I was missing.
 
Ground mount systems, esp in high wind regions, require either a lot of concrete or a lot of excavation, or a combination of the two. For the DIY Unirac system I looked at, I would have had to drill 14 holes, 8' deep, 12" diameter and fill them with concrete. I'm 100+ miles from the nearest ready-mix plant, so either I'd pay a small fortune for a truck or two of concrete, or have to buy a couple of pallets of cement and spend countless hours feeding a mixer. And that assumes I could find anyone to bore the holes. Like most tractors, mine doesn't have down-force on the 3pt hitch, so a PTO driven auger doesn't work - you need either a drill rig or maybe a skidsteer with an auger on the front.

I ended up going with Osprey mounts which use duckbill anchors like Bluedog255 suggests above. The anchors are pull-tested during installation to verify holding strength.
I was just looking at the videos on the Osprey site. How exactly does that work, i.e.how do you get the duckbills into the ground, and how deep are they? Is the test tool something you rent, or did you have someone do that install for you?
 
That actually seems pretty reasonable. If you buy a 32 panel Sinclair ground mount and a truckload of concrete then you're almost at that price without even including labor.

That being said, you can build a mount that will withstand 100mph wind for half that price or less if you buy a lot of the materials used off of Facebook marketplace or similar.
 
I used 3 inch (3 1/2 OD) used oil pipe, its very heavy gauge. paid about 500 for each 32 ft ground mount
paid 250 for a guy with bobcat and 12 inch auger to dig 3-4 ft holes, 6 for each array
each hole took about 6 bags concrete
went with all ironridge engineered system, each 32 ft mount ran about 1500 or so in parts x-100 racks
treated, primed, painted all oil pipe
its solid
 
Ground mount systems, esp in high wind regions, require either a lot of concrete or a lot of excavation, or a combination of the two. For the DIY Unirac system I looked at, I would have had to drill 14 holes, 8' deep, 12" diameter and fill them with concrete.
How are you coming up with 8 foot deep holes? Is that what the Unirac company specifies? That really seems extreme to me.

I bought a 4.5 cuft HomeDepot mixer, and basically did everything myself, batch by batch. I have a 2-ton pickup, so I'll pick up the portland cement in one load, and the sand and gravel in the next. My truck could carry up to three 1 cubic yard totes of sand and gravel at a time, that I would pick up at HomeDepot. I rented the auger from a rental shop for I think, 80$ per day.

For you, I'd envision renting the auger on Saturday morning, with a side trip to pick up the cement. Drill all the holes Saturday. Then pick up the sand and gravel on Saturday afternoon after dropping the auger back off. Start pouring concrete Sunday morning. I think I could have half the holes poured in a day?
 
I was just looking at the videos on the Osprey site. How exactly does that work, i.e.how do you get the duckbills into the ground, and how deep are they? Is the test tool something you rent, or did you have someone do that install for you?

I hired an installer - I'm too old for that sort of thing. They used the biggest hammer drill I've ever seen to drill 1" diameter holes, about 3' deep. My soil contains virtually no rocks for 300', so while drilling is an effort, it's not like it would be if you're drilling into granite.

Osprey has a special tool that uses an impact driver to pull the anchors and a strain gauge measures the force. The tool broke on the job and we used my tractor plus the strain gauge to pull the cables to 1600 pound test.
 
How are you coming up with 8 foot deep holes? Is that what the Unirac company specifies? That really seems extreme to me.
That's what the Unirac design tool comes up with. You can get by with shallower hole if you go 18" diameter. Less drilling, more concrete. Pick your poison.
I bought a 4.5 cuft HomeDepot mixer, and basically did everything myself, batch by batch. I have a 2-ton pickup, so I'll pick up the portland cement in one load, and the sand and gravel in the next. My truck could carry up to three 1 cubic yard totes of sand and gravel at a time, that I would pick up at HomeDepot. I rented the auger from a rental shop for I think, 80$ per day.
Two hours each way to the nearest Home Depot or anything remotely equivalent. 2.5 hours each way to an equipment rental. You're not going to drill 8' deep 12" holes with a two man auger, or at least I'm pretty doubtful.
For you, I'd envision renting the auger on Saturday morning, with a side trip to pick up the cement. Drill all the holes Saturday. Then pick up the sand and gravel on Saturday afternoon after dropping the auger back off. Start pouring concrete Sunday morning. I think I could have half the holes poured in a day?
You must live "in town". :)
 
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