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Hey all,

I'm planning on adding to my existing 4kW array by installing some panels on a flat roof car port. It will have some 34/1000 metal profile sheeting for the roof. I'm wondering what kind of spacing is needed between rows of panels. It's a very awkward shape car port, in between garage and house, and should be able to fit 2 rows of 3 panels, and maybe, 1 or 2 more at the back depending on spacing. They'd be facing approx 235degs.

Also, is it worth going with adjustable mounts so I can change the panels angle a few times through the year? Any recommended adjustable mounts for that, or is it easier/better to go with fixed mounts? Obviously the higher I angle the panels from flat, the bigger the spacing needed between rows due to the shading increasing.

Thanks.

Might be worth using PVGIS to input possible panel layouts and angles to see what difference to the output is.

Where are you?

Off grid or on grid?

What is more important, production on dark winter days or a maximum year round total?

Play around with https://re.jrc.ec.europa.eu/pvg_tools/en/#PVP to see if you'd be better with a larger flat array or two angled arrays.

I think rule of thumb for UK is spacing should be 3 x height

Thanks for the quick replies.

We're down in Cornwall, on grid. We're looking at adding batteries, and our existing 4kW array faces 170degs so not quite south, and is a good pitch on a garage roof about 30/35degs.

So, I think I'd be wanting to supplement the existing generation to charge the batteries rather than go for absolute maximum generation, which would just be adding more to the existing generation which maybe couldn't add any more charge to batteries due to max charge rate from a battery inverter. This is just my initial gut feeling though, and it may actually be better to go for max generation as the 4kW array wont be generating max very often?

A flat array would avoid any hassle in shading and extra cost from mount. Hmm....

What are the dimensions of the roof? and which orientation is south?

Why don't you go with "jumbo" panels?

Eg these ones (https://www.itstechnologies.shop/collec ... olar-panel) are c. 2.3m high.

Dimensions, well here's a sketch, not easy to work out whats best -



Whats the major benefit from those jumbo panels? Do they offer more kW/m2? That would be good.

AlBargey wrote: ↑Tue Apr 05, 2022 11:38 am Play around with https://re.jrc.ec.europa.eu/pvg_tools/en/#PVP to see if you'd be better with a larger flat array or two angled arrays.

Just had a look at the above and compared the estimate of 3444kWh for my 3.87kWp system against my average yearly production over 11 years, and it shows just a 2.5% variation.

Thanks for the help here. I found this site via a link in an email from Midsummer Wholesale - https://easy-pv.co.uk/home and using this can create my weird shape roof and play around with panels. So using this in conjunction with the PVGIS site, have come up with



So, with 8x365W panels at 0deg inclination, annual output = 2615kWh
7 x 365W panels at 30deg inclination (assuming they will even fit with the extra spacing needed?) = 2488kWh

So, to answer my own question, it seems better to put the panels flat, and I only need to add 1 extra panel and that more than compensates for the lack of inclination.

Sorted!

"K2 base" do a helpful tool to orientate panels and generate a shopping list of mounting parts. Might be worth plugging your roof shape into that and see what comes out.