DIY ground mount solar PV install

[joe90]

3 hours ago, Ed Davies said:

Wouldn't a DIY system to jack a significant number of panels up and down likely twist them at least a bit ?

 

Not if the vertical elevation was diagonally braced.

[Jeremy Harris]

@ProDave, I see what you mean about PVGIS.  I've just spent the morning doing battle with its non-CSV format .csv files.  I seem to remember that the .csv files from PVGIS used to work OK, but now it seems they download minus the commas as delimiters, which makes them pretty awkward to use.

 

I've also just been running some estimates of our energy usage through the year, subtracting the usable PV generation and trying to see whether or not it's worth opting for an E7 tariff or not.  Not sure yet, but over the whole year it seems that we're probably going to be about 50/50 peak rate/off-peak rate, if I optimise winter loads for off-peak times.  It all hinges on the standing charge I suspect, but I'll post the details of the sums in another thread, rather than clog this one up.

[Ed Davies]

5 hours ago, JSHarris said:

I see what you mean about PVGIS … but now it seems they download minus the commas as delimiters

 

They're tab characters. Most spreadsheets should be able to import them easily enough though you might need to select the tab-separator option on the import/open page.

 

CSV is a terribly badly defined format even when it's interpreted as “comma separated values” if any of the fields can contain commas. E.g., some software thinks all strings need to be quoted, others that only ones containing commas need to be then there's the question of how you escape quotes in quoted strings and whether new lines are allowed in quote strings, etc. Interpreting it as “character separated values“ and picking a sensible character like tab at least avoids that pain.

[Jeremy Harris]

My only real experience with CSV is when I wrote the code for logging data to USB in our house monitoring system.  I just made sure that the delimiting characters between fields were commas (no spaces) and used CR/LF as the EOL marker.  The two spreadsheet programmes I've used with files from this (LibreOffice Calc and Excel) seem to be able to natively import CSV files in this format with no glitches, so I get columns of data, with headers, all in the right cells.  I'd no idea that a tab delimited file could also be referred to as CSV, seems a bit counter-intuitive to me.

[ProDave]

It is a bit of a fail when your "comma separated variables" file, does not have any comma's in it.  There is even a clue in the name. 

[Ed Davies]

https://en.wikipedia.org/wiki/Comma-separated_values

 

Quote

In addition, the term "CSV" also denotes some closely related delimiter-separated formats that use different field delimiters, for example, semicolons. These include tab-separated values and space-separated values. A delimiter that is not present in the field data (such as tab) keeps the format parsing simple. These alternate delimiter-separated files are often even given a .csv extension despite the use of a non-comma field separator. This loose terminology can cause problems in data exchange.

 

¯\_(ツ)_/¯

[ProDave]

So I went and pegged it all out on the ground and found it was a bit tight for space, one end of the array would have been under overhanging tree branches.  So a bit of re modeling with the "cad system"

 

By putting the panels landscape, and stepping the rows gets the width down. Not the prettiest arrangement but practicalities dictate.  It increases the depth but I have plenty of that.

 

Other news, I have been busy on ebay.  I wanted 2 generation meters, but found someone selling 4 of them for less than the cost of buying 2, so I will have a spare or 2 to put on the market place.

 

And I have been looking at inverters, and just ordered one of these https://www.ebay.co.uk/itm/Trannergy-SGN4000TL-Solar-PV-Inverter/182792629582?hash=item2a8f4a2d4e:g:fX8AAOSwJixZy6Os

 

With todays ebay sale code, I got it for £255

[ProDave]

So back to the mounting frame.

 

My initial thought was some fence posts to make the raised / sloping structure and standard aluminium mounting rails for the panels.

 

For my 16 panels, I will need 8, 4 metre long mounting rails and clamps.  Best I have found so far is in the region of £400.  That's too much.

 

Unless someone can point me at some significantly cheaper mounting rails, then timber decking joists are looking more attractive.

[PeterW]

Scaffold poles and Kee clamps would be cheaper and stronger at that price 

[Onoff]

Unistrut as said previous then copy these clamps?

 

https://www.m.ebay.co.uk/sch/i.html?isRefine=true&sid=gatwick05

[ProDave]

Okay, am I reading this correct, ten 6 metre lengths of unistrut for £161?  That sounds a bit more like it https://www.ebay.co.uk/itm/10-X-6M-UNISTRUT-LENGTHS-41MM-X-41MM-OR-41MM-X-21MM-PRE-GALV-GALV-CHANNEL/172216988267?hash=item2818eeb26b:m:mG19p5Oj7xPYbVQK22gXREw

 

Fix the panels with M6 channel nuts, bolts and penny washers, why make it complicated?

[newhome]

8 minutes ago, ProDave said:

Okay, am I reading this correct, ten 6 metre lengths of unistrut for £161?  That sounds a bit more like it https://www.ebay.co.uk/itm/10-X-6M-UNISTRUT-LENGTHS-41MM-X-41MM-OR-41MM-X-21MM-PRE-GALV-GALV-CHANNEL/172216988267?hash=item2818eeb26b:m:mG19p5Oj7xPYbVQK22gXREw

 

Looks right. 10 x 6M lengths of 41mm x 21mm pre galv plain. The other options are more expensive. 

 

This listing has no other options to pick so is more explicit. 

 

https://www.ebay.co.uk/itm/10-X-6M-UNISTRUT-41MM-x-21MM-PRE-GALV-PLAIN/173353424224?hash=item285cab5560:m:mG19p5Oj7xPYbVQK22gXREw:rk:58:pf:0

 

 

[ProDave]

I will probably choose the 41 by 41 section pre soltted for £202, should be stronger and easier, for not much more.

[Stones]

33 minutes ago, ProDave said:

Okay, am I reading this correct, ten 6 metre lengths of unistrut for £161?  That sounds a bit more like it https://www.ebay.co.uk/itm/10-X-6M-UNISTRUT-LENGTHS-41MM-X-41MM-OR-41MM-X-21MM-PRE-GALV-GALV-CHANNEL/172216988267?hash=item2818eeb26b:m:mG19p5Oj7xPYbVQK22gXREw

 

Fix the panels with M6 channel nuts, bolts and penny washers, why make it complicated?

 

What are you thinking in terms of brackets between panel and unistrut - L or Z brackets?

[ProDave]

Just now, Stones said:

 

What are you thinking in terms of brackets between panel and unistrut - L or Z brackets?

For "between panels" just s simple unistrut channel nut, bolt, and washer, square washer if I can find one.  It will need some form of L or Z clamp to clamp the outer edges of the end panels.

[newhome]

8 minutes ago, ProDave said:

I will probably choose the 41 by 41 section pre soltted for £202, should be stronger and easier, for not much more.

 

Postage is a bit less on this one - just because I know you hate to overpay 

 

https://www.ebay.co.uk/itm/10-X-6M-UNISTRUT-LENGTHS-41MM-X-41MM-PRE-GALV-SLOTTED-RUSTPROOF-WEATHERPROOF/173356720599?hash=item285cdda1d7:m:mG19p5Oj7xPYbVQK22gXREw:rk:64:pf:0

 

 

[ProDave]

2 minutes ago, newhome said:

 

Postage is a bit less on this one - just because I know you hate to overpay 

 

https://www.ebay.co.uk/itm/10-X-6M-UNISTRUT-LENGTHS-41MM-X-41MM-PRE-GALV-SLOTTED-RUSTPROOF-WEATHERPROOF/173356720599?hash=item285cdda1d7:m:mG19p5Oj7xPYbVQK22gXREw:rk:64:pf:0

 

 

The forum that keeps on giving.

[Stones]

1 minute ago, ProDave said:

For "between panels" just s simple unistrut channel nut, bolt, and washer, square washer if I can find one.  It will need some form of L or Z clamp to clamp the outer edges of the end panels.

 

So are you thinking of bolting the panels together (I know you were initially thinking of an additional covered storage area) rather than individually to the unistrut?

[Nickfromwales]

13 minutes ago, Stones said:

 

So are you thinking of bolting the panels together (I know you were initially thinking of an additional covered storage area) rather than individually to the unistrut?

Do these things expand / contract at all ?

[PeterW]

Just now, Nickfromwales said:

Do these things expand / contract at all ?

 Yep a little. That’s why the fixings are designed to not be tight - they allow the panels to move slightly as the frames expand and contract. 

 

 

[ProDave]

picture borrowed at random to illustrate the principle

 

The rail (in this case unistrut) will run perpendicular to the long axis of the panels, 2 rails per panel.

 

"between" panels will be clamped to the unistrut with M6 bolts and penny washers bolting into unistrut channel nuts.  So there will be a gap of 6mm between panels that I will seal by covering probably with aluminium tape.  The end panels will need a Z clamp to fix them to the unistrut.

 

Form my panel arangement I will need 8 lengths of unistrut each a little over 4 metres long.

 

I will have 2 rows of panels and there need not be any gap at all between them and they will get the same aluminum tape to seal the joint. 

[Stones]

@ProDave just been having a look at YT - is this what you were thinking?

 

https://www.bing.com/videos/search?q=unistrut+solar+clamps&&view=detail&mid=979FFA8222E0F1D3F7F8979FFA8222E0F1D3F7F8&&FORM=VDRVRV

[ProDave]

1 minute ago, PeterW said:

 Yep a little. That’s why the fixings are designed to not be tight - they allow the panels to move slightly as the frames expand and contract. 

 

 

Good point. Will look again at the "proper" clamps

[ProDave]

3 minutes ago, Stones said:

@ProDave just been having a look at YT - is this what you were thinking?

 

https://www.bing.com/videos/search?q=unistrut+solar+clamps&&view=detail&mid=979FFA8222E0F1D3F7F8979FFA8222E0F1D3F7F8&&FORM=VDRVRV

That's exactly it.  See how plain bolts and washers work fine for clamping between panels, but trying to do that for the end ones and the bolt wants to jump off sideways so needs a proper z clamp instead.

 

He seemed just to use a rubber washer to allow for expansion.

[Stones]

Also, any issues using galvanised steel Unistrut with the panels (I assume aluminium frame)?