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Ground mount recommendations

how hard is it to turn the array? Is there some kind of bearing in there? Assuming you have a sort of telescoping pipe assembly (smaller diameter fixed in the concrete, larger diameter that can spin?) How high do you think one could mount a system like yours above ground?
 
WYtreasure said:
Depending upon the depth to which posts were pounded, that setup could even work in Wyoming. We had 75 mph winds, more than once this Winter. Used oil field pipe is readily available in my area.
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The vertical pipes are 10 feet in length. The 5 1/2 OD heavy wall pipes are 5-6 feet down. Has anyone ever tried to pull out a ground rod? Try pulling these out. They are then welded together horizontally and on the diagonal brace locking them into a unit that is not easily displaced. They have held up to very extreme weather including a close miss to a tornado. More worried about the aluminum iron ridge XR1000 rails than the pipe structure.
 
clsdds said:
The vertical pipes are 10 feet in length. The 5 1/2 OD heavy wall pipes are 5-6 feet down. Has anyone ever tried to pull out a ground rod? Try pulling these out. They are then welded together horizontally and on the diagonal brace locking them into a unit that is not easily displaced. They have held up to very extreme weather including a close miss to a tornado. More worried about the aluminum iron ridge XR1000 rails than the pipe structure.
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Sounds like a perfect world for you and maybe me. All bets are off when it comes to tornadoes, panels just shred away anyhow.
Having a mount already in place to attach replacement panels is the best we can hope for. I'm betting you have such a mounting system. (y) (y)

Hopefully the panels don't ruin the wiring to the rest of the system when they depart the area during a tornado.
 
MarkSolar said:
OMG, missed that, could that be a typo? That would be a 5 ton slab to hold down 5 panels. If it were 2.5 inches thick it would be about 750# which might be a bit light by itself but there's also the weight of the panels and racking so it's probably about 1000#, which seems like it would be close to adequate.
My seat of the pants calculation says large 5 panels are about 90 sqft, a 60mph wind on a vertical flat wall is about 10psf, so that would be 900#. For 120mph wind it's about 40psf so that would be 3600# force on a wall. The uplift will be less than that amount but don't know the angle so can't make a guesstimate.
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Yes I did post 5’x5’x2.5’. I was going by another install that I found online. After you guys pointed out the weight I ran those numbers in a concrete calculator and yes something like 8280# per pad. So yes I have to rethink this.

your pretty close to panel square feet. Mine come out to be 92sqf and I want them at 40* tilt. my local wind load code is a min 110mph. Tamarack rates the rack I purchased @115mph. So maybe 5’x5’x1’ thick? That would be 3325# per pad.
 
MarkSolar said:
You don't mention what climate you're in. If you have frost depth, you either need piers that extend below the frost line or make one floating slab for the whole array to ride on top of. Piers in really rocky soil means you'll probably have to hire someone with a rock drill who can put in ground screws to the proper depth.
If you don't have frost, you can use either precast concrete ballast, or poured in place ballast. They aren't connected together so they will rise and fall differently if you have frost heave, which will damage your panels and/or mounting system. So you would only be able to use them in warm climates.
There are all kinds of ground mount companies, the biggie is Iron Ridge which is expensive. I used Sunmodo, cheaper and more than adequate for residential applications. In all cases treated lumber could work, but for an array your size the warping and twisting of treated lumber may become a problem because it may damage your panels or the other mounting components. It's also more involved grounding the panels if you use lumber because the entire mounting structure doesn't have electrical continuity. I used ground screws but if I had it to do over I would pour a slab and set the mounting bolts in the concrete when it's poured. We're on glacial till and it was very difficult getting the ground screws in plumb and deep enough.
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Mark - did you use the ground screws with the SUnmodo or create footings? I have rocky soil, and I don't think the ground screws will make it far. Sooner just use an excavator and make 24x24 footings that go down 5.5'. It's more concrete but less drilling labor.
 
Beware trenching cost for a long run in glacial till. I'm over $10/ft just for dirt work and it's not finished.
400' trench and five 10 wheelers of boulders went out, same amount of sand came in.
 
JustPractical said:
Mark - did you use the ground screws with the SUnmodo or create footings? I have rocky soil, and I don't think the ground screws will make it far. Sooner just use an excavator and make 24x24 footings that go down 5.5'. It's more concrete but less drilling labor.
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I used ground screws. I agree, if you have rocky soil try something else.
If you dig footings 5.5' deep in rocky soil with an excavator big enough to get through the rocks, you're going to end up with a hole 5' wide. Then you'll have to form up the footing and backfill it without knocking it out of plumb or worse. If I did it again I'd attach it to a concrete slab and get bifacial panels to take advantage of the reflection off the concrete.
 
MarkSolar said:
As long as it doesn't freeze in his location a ballast system will work. But if there are multiple ballast boxes and they heave unevenly, it will damage the rack, panels or both.
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Nope
Ballast system is fine where there is frost. Clay soil wet to dry moves more than frost.
 
WYtreasure said:
Good call. (y)

Whether clay movement or frost heave the panels and/or rack could be damaged.
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You should see the PV installs done around here. It freezes here, usually a low around -20F in the winter for at least a week. So frost gets down to the 5 to 6 foot depth fairly easy depending on snow cover.

Electrical contractors have been installing PV here by driving an I beam directly into the earth for posts. No cement around the posts. These installs are usually around hog barns that require large amounts of electricity to run the ventilation fans.

When you are out driving around the area, you see many of the arrays have posts that have heaved up due to frost. I think it is just criminal what they are doing. But hey, it's cheap and fast.
 
I'm looking more at Sinclair's system (Practical Prepper recommends it). It is relaively thin galvanized. He has videos where it looks like he is just driving it in with a skidsteer mounted driver. But he operates down south (I think in the carolinas) so less frost there. My ground is a fair share of clay and rock - I do not think I could successfulyl drive any kind of beam or post without hitting rock. Auger would probably also hit rock.
I plan to use an excavator and just dig out a few large spaces - hopefully big and deep enough to resist most of the heaving in the winter (yes, many of my projects involve a strong element of hope).
 
JustPractical said:
I'm looking more at Sinclair's system (Practical Prepper recommends it). It is relaively thin galvanized. He has videos where it looks like he is just driving it in with a skidsteer mounted driver. But he operates down south (I think in the carolinas) so less frost there. My ground is a fair share of clay and rock - I do not think I could successfulyl drive any kind of beam or post without hitting rock. Auger would probably also hit rock.
I plan to use an excavator and just dig out a few large spaces - hopefully big and deep enough to resist most of the heaving in the winter (yes, many of my projects involve a strong element of hope).
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He also has a "ballasted" version that I have.
He picks up the phone when you call too.
If you buy his system and his panels the panels are direct mount, no clips, no grounds, just bolt them up. It's ul as well.
My only problem is that the posts are short for the seasonal tilt, If I tilt them where I want them in the winter, I'll be shoveling.
 
Was at the Canadian border last week at Grand Portage. At the rest stop area for High Falls, there is a small PV array beside the parking lot. All they did there was pour a cement pad, I'm assuming with rebar and cemented upright posts into the cement. I should have snapped a photo of it.

Looked like it had been there for some time as the panels were poly.
 
Video of the sinclair ground mount system in action from Engineer 775 (this guy is very respected and knows what he is doing). The video is about the Solark 15, but in it he shows the ground mount sinclair being driven directly into the earth. The sinclair system is engineered, and on an individual piece basis is much less strong then a 5 inch round schedule 80 pipe.

 
Canxane said:
Video of the sinclair ground mount system in action from Engineer 775. The video is about the Solark 15, but in it he shows the ground mount sinclair being driven directly into the earth. The sinclair system is engineered, and on an individual piece basis is much less strong then a 5 inch round schedule 80 pipe.
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Thank you for recommending this video. In fact I would also advise
to review the other more specific 'Sinclair Sky-Rack' videos from Engineer 775:

 
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Been following Engineer775 for a while. I looked into Sinclair but it's a bit pricey (steel has gone up a lot and delivery to east cost is almost the same cost as the materials). I don't have the "luxury" of Carolina clay - loads of rock mixed in with my soil - so driving posts is not an option. I'm considering a DIY solution. It's a 16 panel array with a 30psf snow load and 105 wind rating.
 
JustPractical said:
Been following Engineer775 for a while. I looked into Sinclair but it's a bit pricey (steel has gone up a lot and delivery to east cost is almost the same cost as the materials). I don't have the "luxury" of Carolina clay - loads of rock mixed in with my soil - so driving posts is not an option. I'm considering a DIY solution. It's a 16 panel array with a 30psf snow load and 105 wind rating.
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That is where pounding and welding an array out of steel pipe would work much better than the sinclair. Contact a fence builder.
 
I just watched a guy do his own ground mount for 30 panels out of $300 of scrap metal and some welding - it was interesting to see what can be done. There's a set of them - he got scrapped, galvanized angle iron and welded them into square tubes.... He's in Northern Arizona.
 
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