DIY ground mount

upnorthandpersonal

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Keeping in line with the whole low-cost solar system, building my own braided bus bars, etc. I thought I would see what it takes to build a low-cost ground mount for those 500W 96 cell panels (1310mm x 1956mm). My goals were to make the whole thing simple to build, with minimal tools and simple measurements. And of course, low cost. I waited with this build specifically until end of summer here in Finland, because now one can get some really good deals on deck/terrace impregnated wood since no one is building them anymore vendors are giving discounts. Same for concrete foundations. The results first:

DSC_1794.jpg

DSC_1785.jpg

It's designed to hold up to 6 of these 500W panels, but this one will probably only carry 4.

- Timber to start from was 50x100x4200mm, in total 10 pieces used at a cost of €11 a piece delivered.
- It uses 6 concrete posts (60kg each) and accompanying M20 pillar shoes, for a cost of €30 each delivered.
- Additionally some fasteners and L brackets, maybe for a total of €30, probably less since they were bought in bulk
- The L brackets were also used to secure the solar panels themselves to the frame

Total: €320 including VAT and delivery. Time to build: a few hours; leveling the ground not included.

The beams dimensions were chosen as this would limit the number of cuts and would result in 0 waste. The front lower beam are two beams fastened together. The vertical ones are a single beam cut in half and joined. The cross beam attached to the vertical pillars is again a single fill length beam. The diagonal ones are full length beams in the picture. Either they can be used to support 6 panels, or the excess can be cut off and used as additional reinforcement. The piece of wood that the panels rest on at the bottom was some left over stuff I had around; but L brackets could be used just as well. The front and back rows of concrete posts are 1 meter apart, the posts themselves are 2 meters apart from one another.

The other nice thing about these dimensions is that this results in an almost perfect angle for spring/winter/autumn when the sun is low.
 
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Ampster

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Nice build. You are lucky you don't have the same requirements we do in some jurisdictions. Our rules would require footings dug into the ground to anchor those concrete posts from the uplift created by wind. The trees will help mitigate that. That angle will also shed snow easily. How deep does the snow get?
 

upnorthandpersonal

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How deep does the snow get?

It can get pretty deep, but I'm not too worried about it. This is actually just a test set-up on my 'staging' area to check out new ideas etc.
The footings will still be covered almost completely with gravel as well for anchoring (you can see the terrain being higher to the left of the picture), so the lower panels will see some snow coverage.
 

Shwetaa

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now one can get some really good deals on deck/terrace impregnated wood since no one is building them anymore vendors are giving discounts
That's a smart idea..Is the entire built ready? Can you post some more pictures with the background to get a more clearer idea of its working (My sister really likes such built and would like to see the final version of it)

The piece of wood that the panels rest on at the bottom was some left over stuff I had around
But that would have been a requirement no? So the panels get an extra support. Will you have that above the panel too?

(My apologies if the questions aren't relevant - But I really liked the panel and would like to know more things about it)
 

upnorthandpersonal

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That's a smart idea..Is the entire built ready? Can you post some more pictures with the background to get a more clearer idea of its working (My sister really likes such built and would like to see the final version of it)

Not entirely ready. Probably next weekend - I'll post updates in this thread with more pictures. The solar panels (4x) should all be on by then.

But that would have been a requirement no? So the panels get an extra support. Will you have that above the panel too?

I could have used L brackets for this support instead of a wood support. The same will be present for the panels above this, yes.
 

schmism

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Did you get your 500w panels from china? I looked at getting some of those as It would have allowed me to push closer to my 150v limit of my SCC with just 2 in series (dropping my amps and allowing me to run smaller wire) In the end I figured a gamble on some "used" 345w panels was about the same gamble as trying to get shipped from china.
 

upnorthandpersonal

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Yes, got them in China. Don't do it if you're in the States, import tariffs will increase your cost tremendously. In Europe there are no import duties on solar panels, so you only pay the VAT on top. Shipping was actually quite painless, just have to be patient - mine took two months to make the trip.
 

Hedges

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You can do a ballast ground mount. Just add ballast to the footings and you should be allright. Ive seen quite a few ballast style solar projects.

Since those look like concrete piers only holding the array down by their weight, I would worry about high wind blowing it over.
Leverage works against you with that aspect ratio.
The trees have a secure foundation. How about wrapping a strap around the base and tying top of panel to that?

Otherwise, lots of ballast.
 

Jejochen

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Yes, got them in China. Don't do it if you're in the States, import tariffs will increase your cost tremendously. In Europe there are no import duties on solar panels, so you only pay the VAT on top. Shipping was actually quite painless, just have to be patient - mine took two months to make the trip.
In belgium there is definitly an import duty, and quite expensive
 

upnorthandpersonal

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Als je naar de http://www.invoercalculator.be/ gaat, heb je ook een selectievak 'invoerrechten' die rechtstreeks naar de TARIC database verwijst. Deze invoerrechten staan op 0% voor zonnepanelen over de hele EU. Ik vraag me oprecht af welke andere belastingen/rechten men in Belgie aanrekent buiten de BTW, dus moest je weten welke, zou het graag weten.
 

Jejochen

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Als je naar de http://www.invoercalculator.be/ gaat, heb je ook een selectievak 'invoerrechten' die rechtstreeks naar de TARIC database verwijst. Deze invoerrechten staan op 0% voor zonnepanelen over de hele EU. Ik vraag me oprecht af welke andere belastingen/rechten men in Belgie aanrekent buiten de BTW, dus moest je weten welke, zou het graag weten.
Hmm ok, i wasn't aware the anti dumping tax got cancelled (and a long time ago it seams)
 

PsychoticEpisode

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Nice can we get some closer pics of the build or your sketches of it I would like to build that too?
 

Hedges

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I have a fence running North/South and wanted more kWh during the new peak-use rate time 4:00 PM - 9:00 PM.
There was also a retaining wall nearby.
I had spare rails with top clamps, so mounted those with u-bolts (also pipe and u-channel.) Otherwise, 2x4 lumber would have worked.
The top rail on the fence could slip off, so I used some channel hardware to hold it down.
Basically an erector set for bigger boys.
I would use rigid compression fittings to do that more cleanly if I redo it.
My other arrays are mostly bolted to existing concrete, but in some cases I just drive a 2" rigid pipe into the ground.
(I have pipe threaders, torch, arc welder, rotohammer, so that's how I usually assemble things.)
Those are 327W panels on this array, 165W in the background.
Some of my deck (not shown) is built with 4x4, 2x5, galvanized stove bolts, similar to UpNorth's ground mounts.
I guess those pier blocks have something to tie beams into. The ones I usually see don't, just stack the deck on top.
I've used metal ties that get set in post holes I did, but I also loop rebar around them so tied in to concrete full depth.

fencemount IMG_1120.jpg
 

upnorthandpersonal

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I guess those pier blocks have something to tie beams into.

Yes, like this which screws into the concrete block:

pilarikenka-benders-kiintea-m20-1.jpg
 
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