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Groundwork’s for PV panels

  • 23-12-2019 8:24pm
    #1
    mrblack
    Registered Users Posts: 350 ✭✭


    Have pulled trigger last week for 4.2kWp PV with 2.5Kwh battery under old grant rules - so must have the panels installed and working by end January!

    Want ours to be ground mounted instead of roof mounted as have a suitable sloped south facing area at rear of house that’s a pain to mow.

    Anyone got any pictures of their Irish installation of ground mounted PV panels. Lots of pics of US ground panels but none for Ireland/UK on the web.

    Wondering if this could be a DIY job as want to keep costs low and maximise return. The installers will be sending an engineer in early January to explain but it would be nice to know a bit in advance. If the groundworks cost a lot then up on the roof they will go :-)

    Thanks
    mrblack
    Tagged:


Comments

  • #2
    unkel
    Registered Users Posts: 64,700 ✭✭✭✭unkel


    Ground mounted is much more expensive in materials than roof mounted. It also takes up space. Why would you even consider it?


  • #3
    quentingargan
    Registered Users Posts: 1,627 ✭✭✭quentingargan


    mrblack wrote: »
    Have pulled trigger last week for 4.2kWp PV with 2.5Kwh battery under old grant rules - so must have the panels installed and working by end January!

    Want ours to be ground mounted instead of roof mounted as have a suitable sloped south facing area at rear of house that’s a pain to mow.

    Anyone got any pictures of their Irish installation of ground mounted PV panels. Lots of pics of US ground panels but none for Ireland/UK on the web.

    Wondering if this could be a DIY job as want to keep costs low and maximise return. The installers will be sending an engineer in early January to explain but it would be nice to know a bit in advance. If the groundworks cost a lot then up on the roof they will go :-)

    Thanks
    mrblack

    SEAI has extended the old grant completion date to end Feb, so you will have another month to spare.

    I agree though - ground mounting is a lot more expensive, usually more prone to shade and breakage and takes up space etc.

    If you are doing ground mount, it has to be in accordance with manufacturers instructions of a system that is supported by engineeres reports. It might be cheaper to fabricate your own galvanised rack, but unless it is a proprietary system, SEAI will want engineers reports.


  • #4
    mrblack
    Registered Users Posts: 350 ✭✭mrblack


    quentingargan wrote: »
    SEAI has extended the old grant completion date to end Feb, so you will have another month to spare.

    I agree though - ground mounting is a lot more expensive, usually more prone to shade and breakage and takes up space etc.

    If you are doing ground mount, it has to be in accordance with manufacturers instructions of a system that is supported by engineeres reports. It might be cheaper to fabricate your own galvanised rack, but unless it is a proprietary system, SEAI will want engineers reports.

    OK. Our house is quite high with a slate roof and due to aspect needs the PV panels on 2 or perhaps 3 sides to get all day results. The 70m long strip of garden is on a steep short bank that faces south south west and has no shading at all. Plus I thought that ground mounts should be cheaper than scaffolding roof work etc.

    If it costs more that a few percent extra then up on the roof they will go.

    The extra month of February for install is a relief. I was thinking that if they cant get the install done in time then the grant might be in jeopardy- so that's a stress out of the way!

    Engineer is out next week to survey site and will discuss costs with him then.

    Thanks for feedback!

    mrblack


  • #5
    rolion
    Closed Accounts Posts: 3,362 ✭✭✭rolion


    I did a DIY on the roof and ground mounted.
    See more H E R E .

    The ground level was harder and I planned to be able to adjust the angle for the whole mechanism. To compensate for months of the year. But, got a greenhouse build later under, so I had to stabilise it.
    I had to drill holes by hand, about 90cm deep and 50cm diameter for each 5 poles. I filled them with concrete and fitted stainless metal poles.
    On top of the poles, I fitted 2 extra strong bars and then the standard PV aluminium framework.
    Not hard, not easy but just fun.

    There are lots of systems of ground works.
    From expensive all the way to cheaper ones.
    Much depending of the location, angles and more important … the exposure to wind and weather.
    If the wind gets behind those panels it will push them up like an old sail ship.
    Get a proper hole for foundation.
    Can you fit at the ground level, is there enough front space ?
    I may have some photos and sketches from when I did my homework, it took me almost a year to do all the checks and maths.

    Enjoy it.


  • #6
    mrblack
    Registered Users Posts: 350 ✭✭mrblack


    Hi Rolion, the link does not seem to be working. Can you reset it? Thanks
    Mrblack


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  • #7
    unkel
    Registered Users Posts: 64,700 ✭✭✭✭unkel


    mrblack wrote: »
    Hi Rolion, the link does not seem to be working. Can you reset it? Thanks
    Mrblack

    Link is working fine. Maybe something wrong at your end?


  • #8
    mrblack
    Registered Users Posts: 350 ✭✭mrblack


    unkel wrote: »
    Link is working fine. Maybe something wrong at your end?

    Right, the link wouldn’t work on my android phone using Edge browser as default- But works fine on my iPad using safari!

    Interesting thread. Your metalwork frame is flatter and much higher than I have in mind as my site is sloped at about 45 degrees to the south. I was thinking the base of my panels should be just 2 to 2 1/2 feet above ground to allow easy mowing under them.

    There is a wire mesh fence in the way when the sun is low in the morning but otherwise no other obstructions to cause shading. Surveyor can put me right on that when he comes.

    Any problems with the frame since installation like vibrations in wind or rain?

    Mrblack


  • #9
    rolion
    Closed Accounts Posts: 3,362 ✭✭✭rolion


    Hi,

    Mine was installed higher due to space constraints.
    I didn't had the luxury to expand on the horizontal, like you. I had to "compress" most of the needs on the vertical, in exchange that explains the height.

    See below few screenshots that I found most closer to my likes.
    Some of them are built with the issue of wind AND snow in their design.
    We don't have the risk of heavy snow and for longer periods so you can focus only on the wind shelter and angle to Sun. You can play with any of the Continental ground mounted works just ignore their concerns for snow.

    I will pay a bit more to have it on some sort of flexible - movable - adjustable framework so that I can play with base don the month of the year.
    If I can make it automated, even great.
    Just to move up and down, that will make a huge difference in long time but, can be compensated with more panels in the array if space give you the exposure.

    You may need to leave maybe a meter under to lower angle to allow for service and for grass or vegetation to grow and cut.


    498565.jpg

    498571.jpg

    498566.jpg

    498567.jpg


  • #10
    rolion
    Closed Accounts Posts: 3,362 ✭✭✭rolion


    Few more.

    498569.jpg

    498568.jpg

    498570.jpg


  • #11
    rolion
    Closed Accounts Posts: 3,362 ✭✭✭rolion


    So basically, as per above photos in real life...

    498572.png

    One you sorted the foundation...
    You need to build the steel (stainless or galvanised) framework to match the array size.
    So if you make it 4 panels H by 2 panels V that means 4.5m x 3.5m one "metal window"
    On top of that, you will need to buy the standard kit as for the roof mounting stuff .
    Then, just drill and screw & bolts to the frame that kit.
    On top of it, attach the panels with standard parts, nuts and bolts and anchors as per installation on the roof.
    Very easy...


    However, my dream and work in progress... for two of these,2 x 16 panels :

    498573.jpg


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  • #12
    rolion
    Closed Accounts Posts: 3,362 ✭✭✭rolion


    Few close-up, hope that helps you visualize the link between the metal framework and the PV roof mounting rails.

    498574.jpg

    498575.jpg

    498576.jpg

    498577.jpg

    498578.jpg


  • #13
    jimmyging
    Registered Users Posts: 203 ✭✭jimmyging


    Hi I am close to going with ground mounted non grant for a few different reasons.
    1 It actually works out cheaper
    2 OH not happy to let roofers near our slate and also not happy to have inverter and battery over kids rooms in case of electromagnetic radiation and fire risk .
    3 We have an unused corner of the garden near our garage where we can put the inverter etc out of the way .
    4 We can place the array in an exact south facing position and the panels are more easily maintainable on the ground .


  • #14
    unkel
    Registered Users Posts: 64,700 ✭✭✭✭unkel


    Any link to the ground mounted frames you will be using?


  • #15
    Mr Q
    Registered Users Posts: 984 ✭✭✭Mr Q


    unkel wrote: »
    Any link to the ground mounted frames you will be using?

    Also interested in this. I will be going ground mount and it can get very expensive very quickly for the mounting. 16 panel ground mounts seem to be the size most easily purchased. If you want more it increases quickly i'm finding.


  • #16
    unkel
    Registered Users Posts: 64,700 ✭✭✭✭unkel


    Mr Q wrote: »
    Also interested in this. I will be going ground mount and it can get very expensive very quickly for the mounting. 16 panel ground mounts seem to be the size most easily purchased. If you want more it increases quickly i'm finding.

    16 panels = 5kwp, which is a decent array. You are not allowed go over 6kwp anyway


  • #17
    Mr Q
    Registered Users Posts: 984 ✭✭✭Mr Q


    unkel wrote: »
    16 panels = 5kwp, which is a decent array. You are not allowed go over 6kwp anyway

    The 6kW would be AC side though. You can put more on the DC side, plenty of inverters have up to 1.5 times this allowed on the DC side.


  • #18
    unkel
    Registered Users Posts: 64,700 ✭✭✭✭unkel


    Aye, good you're making that point. Your inverter can have a max of 6kW output on the AC side. Panels are so cheap these days that in some cases it can make sense to oversize the array, to get more juice out of it when the system is not optimal. So indeed you could have a 12kwp array if you want as long as your inverter can only generate 6kW.


  • #19
    Mr Q
    Registered Users Posts: 984 ✭✭✭Mr Q


    unkel wrote: »
    Aye, good you're making that point. Your inverter can have a max of 6kW output on the AC side. Panels are so cheap these days that in some cases it can make sense to oversize the array, to get more juice out of it when the system is not optimal. So indeed you could have a 12kwp array if you want as long as your inverter can only generate 6kW.

    That's true. And on a ground mount in most cases adding panels probably wont be a space issue compared to a roof which could be limited.

    But the mounting is expensive, it looks a bit cheaper to have it made locally for me than buy a full kit.


  • #20
    jimmyging
    Registered Users Posts: 203 ✭✭jimmyging


    I haven’t got down to the specifics with the installer on the type of support . The 2 we have discussed are unistrut and a k frame . I am going to organize the ground works and concrete pouring .


  • #21
    rolion
    Closed Accounts Posts: 3,362 ✭✭✭rolion


    Guys,no offence but where are coming out with get whatever array size and the inverter will get out max 6Kw !!?
    Those that did the proper DIY way...haven't you heard about the max power input on the DC side for any inverter !? That could be done in Amps or in Volts but frying that baby will not look good if you have to return it for warranty...


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  • #22
    ethernet
    Registered Users Posts: 3,568 ✭✭✭ethernet


    rolion wrote: »
    Guys,no offence but where are coming out with get whatever array size and the inverter will get out max 6Kw !!?
    Those that did the proper DIY way...haven't you heard about the max power input on the DC side for any inverter !? That could be done in Amps or in Volts but frying that baby will not look good if you have to return it for warranty...
    That’s a given but I reckon they were referring to ESB’s network limits here: 25A max for single phase. Open to correction though :)


  • #23
    rolion
    Closed Accounts Posts: 3,362 ✭✭✭rolion


    See attached.

    MAX input power matches Inverter type.
    I will give maxim 10% out of boundary to cover for low production of the panels
    So, for a 4.2Kw inverter I will not add a greater than 4.5Kw PV array.

    Even if these days the PV panels are cheap... I am shocked.

    500249.jpg


  • #24
    Mr Q
    Registered Users Posts: 984 ✭✭✭Mr Q


    rolion wrote: »
    Guys,no offence but where are coming out with get whatever array size and the inverter will get out max 6Kw !!?
    Those that did the proper DIY way...haven't you heard about the max power input on the DC side for any inverter !? That could be done in Amps or in Volts but frying that baby will not look good if you have to return it for warranty...

    SMA inverters for one can take 1.5 times the AC amount on the DC side. SMA themselves recommend this in a lot of cases. It is clearly on their spec sheets.

    A SB 6.0 for example can take 9000 watts on the DC side. This is of course once you are within the amps and volts limits. I plan to connect 8kW to one.

    Fronius would be similar i believe.


  • #25
    rolion
    Closed Accounts Posts: 3,362 ✭✭✭rolion


    Mr Q wrote: »
    SMA inverters for one can take 1.5 times the AC amount on the DC side. SMA themselves recommend this in a lot of cases. It is clearly on their spec sheets.

    A SB 6.0 for example can take 9000 watts on the DC side. This is of course once you are within the amps and volts limits. I plan to connect 8kW to one.

    Fronius would be similar i believe.

    Could be,dunno.
    My ABB recomended 10% max 15% more. i will be surprised to find out 1.5x times... maybe that for a split sec and thereafter protection kicks in and warranty voided.

    No time to describe now but somethign to do with when Sun gets out at the boundary of the clouds and / or snow reflections (i wish to have snow here).

    Take care.


  • #26
    garo
    Registered Users Posts: 1,874 ✭✭✭garo


    rolion wrote: »
    Could be,dunno.
    My ABB recomended 10% max 15% more. i will be surprised to find out 1.5x times... maybe that for a split sec and thereafter protection kicks in and warranty voided.

    No time to describe now but somethign to do with when Sun gets out at the boundary of the clouds and / or snow reflections (i wish to have snow here).

    Take care.

    Your own data sheet shows the 4200W able to take 3000W per channel for a total of 6kW. And max voltage and current numbers don’t contradict that.


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