diy solar

diy solar

solar pergola on pavement, only weighted down

I mean if you placed two blocks for foot of array and head of array (per support) and ran tie-down cables, the cable might pull at an angle and drag the block without having to dead-lift it, allowing collapse. If the blocks were joined into a rigid structure, then it would have to lift the upwind block into the air, pivoting over far end of downwind block. Like a ladder collapsing if not locked in position, vs. having to go up to tip over.

A single pipe would be sufficient to keep one block from sliding toward the other. A truss structure would be required to make it strong enough that block actually has to lift for structure to fall over.

If you have a way to convert wind into horizontal and uplift force, the rest is simple mechanics.
 
Hedges said:
I mean if you placed two blocks for foot of array and head of array (per support) and ran tie-down cables, the cable might pull at an angle and drag the block without having to dead-lift it, allowing collapse. If the blocks were joined into a rigid structure, then it would have to lift the upwind block into the air, pivoting over far end of downwind block. Like a ladder collapsing if not locked in position, vs. having to go up to tip over.

A single pipe would be sufficient to keep one block from sliding toward the other. A truss structure would be required to make it strong enough that block actually has to lift for structure to fall over.

If you have a way to convert wind into horizontal and uplift force, the rest is simple mechanics.
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I can connect the legs. If you mean the big 3500lb blocks, I think you are suggesting 21,000lbs of weight. If the panels have 12,000 of lift at 120mph, why 21,000lbs of weight?

I dont see 100mph winds happening here, and if there is there will be dozens of small dumpsters floating by like tumbleweeds that are just going to take out the pergola. My box trailer will also flip into the pergola if the wind is from the east.

I'm ok with overkill for liability, but we are into territory where I will take the risk for the value of the structure and panels themselves. I only care about preventing the panels becoming projectiles.
 
As long as the panels and unistrut staying attached with cables to the weights did not fly around and cause damage to other property, I will take that $2000 bet (value of my array and structure) any day of the week as we will never see that kind of wind in this location in 3 years.
 
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I can't help but point out you suggested the blocks be attached to rigid structure, possibly the base. I was partially satisfying that with the rigid cinder block wall, but with less weight.
 
CableGuy said:
Thanks. I am already now leaning towards larger concrete blocks if the weight recommendations are what's needed.

I am under the impression uplift is the biggest concern with a mostly flat array, and if the blocks are directly below the top of the frame edges, i'm not sure I know what you mean with the struts?
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3 IBC totes on each side full of water would give you 6.5 tons of ballast and take a space of 4’x10’ each or 40”x12’ each
Add a 4th to each side and you’re up to 9 tons of ballast, and emergency water on standby 😅
 
G00SE said:
3 IBC totes on each side full of water would give you 6.5 tons of ballast and take a space of 4’x10’ each or 40”x12’ each
Add a 4th to each side and you’re up to 9 tons of ballast, and emergency water on standby 😅
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I was curious what those pallet size water jugs were called. Can they freeze?

Unfortunatly i think they are cost prohibitive if you add the cost to the wood structure vs just buying a 20ft shipping container, mount the panels on top, and get some extra storage.

Container could be moved with the panels on it, the only downside is a smaller array than planned...
 
You can get insulators for them. I believe the totes themselves can be found often in one’s local area for maybe 100-200 each.
Container would be neat too
 
Since you are preparing for 500mph winds you might as well just mount some turbines while you are at it, effectively breaking the wind force and collecting energy at the same time. I'm only joking, I can't contribute to windforce mathematics, as I don't fully understand it. But from a carpenter standpoint, I think some horizontal 2by rails running along the backside will help solidify the thing, also some 45°corner braces on your center posts running lengthwise with the fascia will prevent it from collaping sideways.

:) Nice design
 
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G00SE said:
You can get insulators for them. I believe the totes themselves can be found often in one’s local area for maybe 100-200 each.
Container would be neat too
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no i dont mean dipping below freezing. i mean they would be cubic yard ice cubes.
 
I should be able hookup 90kW of panels mounted a single 20ft shipping container according to this.
 
Zwy said:
2 feet off the ground, not 8 to 10 feet.
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correct, I thought it was obvious I was not actually comparing a 180 panel deployable array to my project.

I'm going back to the drawing board with sand, I forgot i have access to a tractor. The temporary nature and future disassembly of this project was conflicting with my tendency to over engineer most things. I have an idea to avoid complete disassembly when it needs to be moved. @Hedges I can't make the whole thing a truss, but I can get some big beefy triangles in the right places.
 
CableGuy said:
correct, I thought it was obvious I was not actually comparing a 180 panel deployable array to my project.

I'm going back to the drawing board with sand, I forgot i have access to a tractor. The temporary nature and future disassembly of this project was conflicting with my tendency to over engineer most things. I have an idea to avoid complete disassembly when it needs to be moved. @Hedges I can't make the whole thing a truss, but I can get some big beefy triangles in the right places.
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That's good, I don't think the CMU blocks in your original idea would work very well. Stacked vertically like that and they wouldn't have any stability on their own so you'd be relying on the wood framing to hold them in place.

A board on the bottom weighted down with sand bags stacked however high would hold work well, and the cross pieces could still be integrated in the mass of the ballast.

I suppose you could build wooden boxes to hold sand but I think they would need to be quite sturdy and would lack the inherent stability of stacked flexible units.
 
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