Solar panel positioning

[DeeJay]

I've just been up on the roof trying to work out what size system I can fit up there.
There are a couple of questions that would make a big difference.
1/. Can solar panels overhang by, say 50mm over the end of a steel roof?
2/. Or be raised so they go over the top of a ridgeline by a similar space? ( I realize this would allow the wind to get under)
3/. All the photo's I've seen have the panels lengthways vertically along the roof. Can you run some sideways? IE like a "T" or do they lose efficiency?

Hopefully some of you guys have seen this or can help?

Thanks,
David

[bee utey]

There's no good reason why panels need to fit your roof exactly, EXCEPT councils may require separate approval if you alter your building's roof profile. A bit of a cooling breeze under your panels will aid their output. Some panel sets are fitted on angle brackets to lift them off the roof to a totally different angle, no probs so long as your plans are approved. You can mount panels anyway you like, so long as their fastening system allows it. Most fast fit mounting rail kits aren't designed for anything other than fast fit, a small amount of creativity may be needed.

[Jhonno]

I have mine mounted on manually operated tracking poles, one set mounted vertical and two sets mounted horizontal.

DON'T repeat DON'T purchase your panels from LHP on fleabay, I made that mistake for my upgrade set, very poor performance compared to the originals puchased in 1992, they, LHP, seem to have some difficulty in replying to emails and telephone calls.

[superquag]

You only get what you pay for... anything more is a Lotto win...

Main thing is to mount them due NORTH for all-round performance, mine are on 045 degrees (NE) due to roof line. - They start the inverter about 5 to 8 minutes before the sun pokes its head up.

Pitch is another debatable aspect (sorry, pun...) Mine are on 18 degrees, same as roof. But putting them up to say, 32 would work against me as the afternoon drop off would be earlier and more pronounced.

A friend of mine with a 1.5 system, has his split between NE and NW. Surpisingly, he's getting a good daily average as its producing useable amounts in the early morning and late afternoon. (Mine nose-dives at around 3:30 pm)

I could get around this by adding a third string, aimed for the winter afternoon sun. (worst condition)

There is NO reason why they cannot be mounted sideways... except "Tradition" . Note that your mounting rails would then need to run vertically, in order to get the approx. 2/5 & 4/5 mounting points on longer sides.

ie, running the mounting rails sideways - as 'normal' - but spaced closer might not be a Good Idea as the panels would be supported on the top/botton ends, with too much length to flap in the breeze...

But running them at right angles (vertically for sideways panels) will increase the labour content...and the Grizzle Quotient from the installers....

[Vern]

David, whats the roof area you plan to fit them on?. Generally a panel measures approx 808mm x 1560mm (190-200w panels), allow 20mm between panels for clamps and 40mm at either end. Panels can be arranged in either portrait or landscape, (vertical or horizontal), vertically you use less rail to mount them to and can generally get more panels on. Generally you like to have a 'useable area', which is an area where you can still walk around the array (300mm around the edges). Running up ver the ridge is not really a problem, some people don't recommend it due to wind loading, but the framing system is engineered for well over 100klm winds, and if in doubt, more feet can be added.

[DeeJay]

Damien,
I'm looking at Renesola 245w panels 990x 1665 ( made on Suntec assembly line I'm told by the rep, just rebadged) They are supposed to install next Wed but I think they have made the same mistake as a previous company in that they have to fit according to tile spacing & there simply isn't the room. I have a perfect steel roof over the upstairs verandah but it is a 3.3m span & can't be walked on, so all too hard for the installers, so we can only use the house roof which is Tiles.
Company is Solargain..

[Vern]

David,
Suntech make a lot of the cells for different panel manufacturers, i guess its a bit of 'the fish john west rejects', they pick and sell there cells. Some companies buy good cells from them, some buy the lesser quality one. Renesola have a good reputation though, Suntech have a new 200 watt panel out now called 'Pluto', its the same size as the 190w but with better output, they seem to work really well. I have Tianang panels in the shed for my place, these look identical to suntech 190's but are cheaper, been getting really good reviews in the likes of Renew magazine, each panel comes with a test sheet of its performance, majority of the panels are performing slightly above 190w.

Which inverter are you using?

When they come to do your install, make sure you have spare tiles, as they do break. With the brackets they use for the tile mounts, the back of the tile that sits on top of it will need to be ground back to stop the tile from cracking from resting on it, i haven't done one install where the tiles have not needed grinding, i have seen jobs where the tile was not ground and has cracked, causing water damage to the house.
hope it all goes well

[DeeJay]

Thanks for the reply, I had the roof resprayed a few years ago, he did a really good job & even offered to spray my spare tiles (I never thought of that !!) fingers crossed, I have 6 spares.
The inverter is a Aurora outdoor 3kw, as one set of 6 panels ( 245 watt) is facing NNE & the other 6 facing NNW, give or take. If they say they can only fit 5 each roof section I'm going to crack it, as I'm already cranky they are'nt interested in the sun deck roof which can fit another 5 panels, OK it needs spreaders to walk on, but was put in the too hard basket pretty rapidly...

[Vern]

Anything is possible, but as the aurora only has 2 seperate inputs, then nne and nnw will use them up. I have a 6kw aurora for my place (yet to get it up and running (time)), they are a great inverter, a little noisier, but still a really good performer, SMA would be my #1 choice, then Aurora #2, but they are that close in perfomance levels, its non debatable.
If you were to use the sun deck, then you would need a bigger inverter, and need to series/parrallel 2 of the strings.

[DeeJay]

The inverter subject could be another way of edging money out of me ( skeptic aint I ) as we started with a SMA & then the rep rang me with "good news" as they could utilise an Aurora. I kinda said we agreed on a unit & why change & he said he was just trying to save me a couple of hundred $$. My Scottish heritage came into play & I agreed. From the paperwork that later arrived it is nearer to $90.00.

Cheers, David