Ground mount PV - ground screws

Orebro

Has anyone ever used ground/foundation screws for a ground mounted PV system (or anything else like decking etc): https://foundationscrews.ie/products/

Looks like roof mounting is a no go for me and I have room for a ground mounted system, thinking something like these would give a good foundation and with a metal solar mounting frame for the panels. Saw Robert Llewlynn use them in a episode of Fully Charged recently but it was a very brief clip with no details.

munsterfan2

I'm putting my own in, picked up 12 x panels yesterday ( 375w @ 80e each :-) ). I have some galvanised scaffolding poles, so plan is to put them in concrete and use additional poles / unistrut to mount the panels.

TerraSolis

https://www.boards.ie/discussion/2058314792/ground-mount-pv-ground-screws

My ground mount is on ground screws - Midsummer used to sell Sunfixings' ground screw system which is how I bought mine but they don't sell them anymore. Solartricity sell TreeSystem. You could also contact either TreeSystem or Sunfixings directly and see if they'd sort you out. Worth calling midsummer to ask about it too.

Orebro

Did you install the ground screws yourself or did you get the lot done by an installer? Was it difficult? Just wondering as they make it out to be a DIY job if you like.

TerraSolis

Yup installed them myself - not too bad. Would definitely depend on the size of the screw and the ground condition. Has the potential to be a bit of a balls or just really grand.

DC999

https://www.boards.ie/discussion/comment/121140975#Comment_121140975

What did you use to get them into the ground? I've seen machines like a small digger yoke that rotates them. No idea how you diy that twisting motion needing a lot of force

TerraSolis

https://www.boards.ie/discussion/comment/121141057#Comment_121141057

Glad you asked - I didn't get a mini digger with an auger in to do it in like you're supposed to. I borrowed the necessary adapter for the mini digger from midsummer (https://images.app.goo.gl/hxCRJDg5GsGpN5HR7) and shoved a long spike crowbar into the hole. Then walk in circles and put some back into it. If you hit a rock, cry and grab a shovel.

DC999

https://www.boards.ie/discussion/comment/121141492#Comment_121141492

Classic - old skool. Fair play!

graememk

https://www.boards.ie/discussion/comment/121141492#Comment_121141492

Love it, Would have done the same.

Mini digger wouldnt get past the rock either!.. or a bigger bar.

Some of the foundations some people put in for solar.. well ive hung 16 ft gates with half that. and they only move when someone takes the corner too tight with a trailer and puts racing stripes on it.

TerraSolis

https://www.boards.ie/discussion/comment/121141828#Comment_121141828

That's true!

Yeah I'm not a fan of the concrete pads the size of the new Dublin Airport runway that some are putting ground mounts into. In terms of impact on the land here, I can just unscrew these one day if I'm every decommissioning or moving the system.

The ground screws are solid as hell... brother's partner for scale 😅 (Nobody panic - the oil tank doesn't get used).

DC999

https://www.boards.ie/discussion/comment/121141828#Comment_121141828

I’ve seen them used on YouTube for a large garden room (in UK) so that’s what I was asking for as might be a future project. They replace the concrete runway people use.

The Completed Project - Garden Room #8 - YouTube. They talk about the force needed to pull them out - he doesn’t say it in the ground but sounds like the Hulk isn’t pulling them out. They used them on clay (UK) and the screws allows some movement which is good when there is timber on top (for a garden room, not a solar array). Runs from 2’45 in for about 90 seconds.

graememk

https://www.boards.ie/discussion/comment/121141947#Comment_121141947

How far do you need to put them in?

I suppose even using some 8ft strainers and putting them in with a postdriver/digger would work too. If being really proactive putting extra perseverative on them too(although the creasote ones are off the market now)

Not planning on actually putting in a ground mount, still have plenty of shed roof space. But like discussing ideas

TerraSolis

https://www.boards.ie/discussion/comment/121142214#Comment_121142214

The ones I used were 1.5M long and I drove them in about 1.2M as per the specs I was given. I'm fond of my ground-mount - it's orientation is flawless. They double-row portrait config ends up very tall though. The odd day I catch myself thinking single row portrait setup, whilst more expensive, would've been neater/nicer from a landscaping point of view.

munsterfan2

Trying to decide on a fixed angle mount or adjustable, from table below, is there much to be gained by adjusting the panels a few times a year or is it more convenient to leave it at 53'. I looked at a few studies and there really doesnt seem to be much of a gain but I'm open to correction.

Angle of Sun Optimum Panel Angle

21/12  -  Winter Solstice          13 degrees   77  

22/09  -  Spring/Autumn Equinox   37 degrees     53

22/06  -  Summer Solstice          60 degrees     30

Big Lar

@munsterfan2

If this is any help, I did some calculations a few years ago using https://re.jrc.ec.europa.eu/pvg_tools/en/tools.html, there are gains to be had but I decided that it would not be worth the extra cost and effort. Like one or two extra panels would over any gains/losses.

Its based on 4Kwp facing South

munsterfan2

Thanks @Big Lar

that gives me the following: mmmm decisions decisions

Big Lar

https://www.boards.ie/discussion/comment/121146283#Comment_121146283

Like I think you need to weigh it up:

Adjusting the panels will mean more moving parts = Extra fabrication costs and extra work and extra point of failure

Adding a few more panels if you have room = Extra one off cost

unkel

I have panel strings at very different angles and there really is very little in it. Just max the number of panels you can fit and fit them in the easiest and cheapest way. It's 2023 when a panel can be had for under €100. Not 1993 when panels were extremely expensive and you needed to squeeze every Wh out of them in every possible way.

bunderoon

https://www.boards.ie/discussion/comment/121142744#Comment_121142744

For a single row of panels, I wonder what would be the depth needed. IE: 800mm in the ground as opposed to 1200mm...

The wind comes face on where I live and the array I'm thinking about would be set up against a large ditch and hedge row. So pretty sheltered.

munsterfan2

Just never seem to have enough free time for this, but some progress made last week - 1 row of 6 panels up. Hopefully get the second row up, cabled and get the spark to come connect before January

unkel

https://www.boards.ie/discussion/comment/121471924#Comment_121471924

Oh, to have plenty of land. I'm not jealous 😁

Good job, well done!

SouthWesterly

https://www.boards.ie/discussion/comment/121471924#Comment_121471924

Nice job what did you use to connect the panel support poles to the horizontal ones.

Some more photos would be nice if you've time

I wonder how many panels I could fit in my 4 acre back garden 😁

ColemanY2K

https://www.boards.ie/discussion/comment/121142925#Comment_121142925

The column in yellow.

Using PVGIS I worked out that my 7.79kWp array would generate an additional 322kWh over the course of the year. More than all of December and just shy of January's figure.

Edit: the dream would be 33c for FIT lol. I'm with Flogas and @ 20 cents gives me in theory an extra €65 / year.

Ubbquittious

https://www.boards.ie/discussion/comment/121471924#Comment_121471924

You're not being affected by the global warming anyway

munsterfan2

Physics is a b*tch... :-) As I was on a slope the second row of panels needed to go quite a bit higher to catch the winter sun, so instead of the supports being 30cm & 1.8m they were 1.2m & 2.7m. Torque = force * length of lever giving

On the bright side, only one panel damaged, wiring ripped from back and I can cut the frame and reuse, just maybe not as high :-)

slave1

For my ground mounts I went 18" wide and 30" deep, used the same steel as you but also welded "wings" at bottom to set into concrete better, all still good this AM

TimHorton

https://www.boards.ie/discussion/comment/121652755#Comment_121652755

Looking at 10 x Panels in a 5x2 Portrait Config, but will use 3m x .4m x .4m Ballast Blocks. How much concrete did you use?

munsterfan2

https://www.boards.ie/discussion/comment/121654888#Comment_121654888

Nowhere near that - two bags of post 10 per pole - so 640kg in total. Didnt take into account that the ground is very wet there when it rains a lot. One of the poles bent, while the other 7 pulled the concrete out of the ground.

TimHorton

I live in a very exposed spot. I will be following the plans I.posted.

slave1

https://www.boards.ie/discussion/comment/121655308#Comment_121655308

My area is wet too so I used a tub and placed concrete and poles into that, then back filled around the tub and finished off with some more concrete