PV Quotes invited, 4kw Watford, Herts (1 mile off Junction 19, M25)

[Smidgen]

Hi,
It was suggested to me yesterday that I post on here for quotes for a PV Array. A couple of folks have contacted me but as I had put "South" in the event they may be too far away.

Info I think you need is as follows:
Property pretty much south facing,hipped and gabled but I think there is plenty of room for a neat oblong install on one roof. No idea of the pitch.
3 storey house, I think you may be able to get height to avoid tree shade
No scaffold needed? Access would be from a flat roof which would need boards to protect it (we have a scaffold tower on site, but you would need to bring your own scaffold boards).
Rosemary clay tiles.
It is a must that the installation raises the house into bracket D for the FIT. I have run a guestimate through the EST website and they conclude that a 1kw system and some more loft installation (we will do) would bring us into D. But a lot of there questions we cant give yes/no answers to and the assessment all seems VERY arbitrary.

If you want to pm your direct email I will send latitude/longitude and photo of the area envisaged.

Please say whose panels,inverters, monitors you will suppy so we can compare like for like with other companies.


Thank you
[h=1][/h]

 

[Smidgen]

Not sure if this helps but I do have products in mind which people might like to comment on,

Sanyo/Panasonic panels seem to have the best efficiency
Geo Chorus monitor
Not sure about inverters, but most companies seem to offer the Samil 4000, or more expensively the SMA Sunny boy?

Thanks

 

[FB.]

Sanyo/Panasonic panels seem to have the best efficiency

It's not all about efficiency. It's as much about power output relative to the cost. I'd have no problem with an array of "old technology" polycrystalline panels made in China if they priced competitively against the Sanyo/Panasonic on a total generation:total cost basis.

Panasonic (Sanyo) panels are very expensive but don't deliver much additional performance except in very hot sunny climates (e.g. Mediterranean) where their superior temperature coefficient comes into play (hot, sunny, in the UK?). You'd probably be adding 25-30% to the total cost of a 3-4kW system but only gaining about 5-10% electricity generation.
Their main advantage is that they are smaller for the same power output (about 80% the size of a similar-wattage panel).

I found that the saving from installing Chinese panels instead of Japanese would allow me to save enough money to completely replace all the panels once during the lifetime of the system (although the panels came with a 20-odd-year insurance-backed warranty). And if I did replace the panels the chances are that technology would have improved (just like mobile phones get smaller and more powerful for little difference in cost).

Not sure about inverters, but most companies seem to offer the Samil 4000, or more expensively the SMA Sunny boy?

I opted for the opposite strategy: Chinese panels with European inverter, on the grounds that panels are relatively simple with no moving parts (the Chinese can surely get that right?) whereas the inverter has moving parts in the form of a cooling fan, and has an on-board computer which analyses and optimises the power flows.

 

[FB.]

If you want to pm your direct email I will send latitude/longitude and photo of the area envisaged.

Why not make a couple of screenshot captures from google maps and post the pictures on this topic?
It'll allow a lot more input and discussion as to the pro's and con's of how to get the best from your roof.

(I'm not an installer by the way - just someone who is enthusiastic about renewables)

 

[Smidgen]

Thanks, I have no idea what relative parts/panels cost and not anti far east manufacturers. All good points. Perhaps I shouldnt have stated what I fancied. Anybody who wants to quote probably uses what they feel works best as a complete assembly.

 

[Ian-LS]

I wouldn't post a photo of your property on here as you'll get too many differing opinions. You'll get some good quotes and designs from people on here by PM and e-mail.

If the other installers haven't mentioned it then I'd advise getting Hookstop rosemary clay replacement tiles as they reduce tile breakage to almost none. One of the key considerations when installing on rosemary clay tiles.

 

[SolarCity]

+1 to Ian-LS Hookstop recommendation.

 

[saint]

If space isn't an issue they don't pay out for Panasonic / Sanyo. I prefer solar limpets to hook stop option personally. Samil have proven to be efficient and reliable over the last year.

 

[Worcester]

A recent hookstop installation : https://picasaweb.google.com/113260...&authkey=Gv1sRgCPOJk_LUsZ7-Tw&feat=directlink

Roof and working edge protection will still be needed, so some scaffolding will be needed.

We've done nearly 100kW each of solar limpets and Hookstops, - prefer hookstops.

The last image in that link above is a 20kW solar limpet

We find we still occasionally end up with broken tiles under a limpet, not had one yet under a hookstop.

 

[SibertSolar]

Hookstop are very good, we'll have the "jump up and down trying to break the tiles" stand thingy at the show in Oct if anyone is there and fancies a go!

 

[Gavin A]

Hookstop are very good, we'll have the "jump up and down trying to break the tiles" stand thingy at the show in Oct if anyone is there and fancies a go!

you sure you want me to?

I'd just break all the ones next to it...

 

[Smidgen]

Thanks again for all the advice. I wouldnt have known to ask about what fixings will be used below the rails. I have purchased some spare tiles as I dont expect the installers to float over the roof when they install.

 

[FB.]

I'd slate an installer if they broke my roof tiles.

 

[Smidgen]

:clap:Ha Ha Ha

 

[SolarCity]

When we use hookstops, we rarely break a tile. Which generally means we end up with 30odd spare at the end of the job.

 

[saint]

A recent hookstop installation : https://picasaweb.google.com/113260...&authkey=Gv1sRgCPOJk_LUsZ7-Tw&feat=directlink

Roof and working edge protection will still be needed, so some scaffolding will be needed.

We've done nearly 100kW each of solar limpets and Hookstops, - prefer hookstops.

The last image in that link above is a 20kW solar limpet

We find we still occasionally end up with broken tiles under a limpet, not had one yet under a hookstop.

Worcester - have to say those anchors fit those tiles really well. What make are they?

 

[Worcester]

@saint Redtip, same as the hookstop, Andy @ Sibert can get them for you Redtip Hookstop plus Redtip M100 for plain tiles
Final picture was Solar Limpets

Neither of those two are the cheapest option, I know I over engineer roof fixings, however in my book it's got to last 40 odd years . On a 4kW system that typically means about 50-60 roof hooks (depending upon layout and wind loadings), so it adds about £250 -£300 to the cost over a universal roofhook - Is it worth it? We won't install any other way.

@FB lol.

 

[saint]

Thanks Worcester. doesn't seem to be any adjustment in the anchor where as the limpet allows you to string off the rail for a nice and flat array.

50-60 anchors on a 4kW? OMFG!

@saint Redtip, same as the hookstop, Andy @ Sibert can get them for you Redtip Hookstop plus Redtip M100 for plain tiles
Final picture was Solar Limpets

Neither of those two are the cheapest option, I know I over engineer roof fixings, however in my book it's got to last 40 odd years . On a 4kW system that typically means about 50-60 roof hooks (depending upon layout and wind loadings), so it adds about £250 -£300 to the cost over a universal roofhook - Is it worth it? We won't install any other way.

@FB lol.

 

[Worcester]

In the simplest possible install, 4 rails, 8.2 m long @ 900 spacing closed up to 450 at each end to cope with -ve edge pressure from wind loading = 11 hooks rails per rail = 44 hooks, can't do it with less than that and ensure that the load is evenly spread across all the rafters. Now end up splitting over two roof areas, and you soon add in another dozen hooks.

 

[Gavin A]

looks like overkill to me on most roofs tbh.

Our SE reckons most traditional roofs with perlins and 50 x 75mm rafters, the point of concern is the perlin's ability to take the entire extra loading of the array, rather than the capacity of any of the individual rafters (so we've strengthened a fair few perlins).

Which makes a lot of sense if you consider that modern trussed roofs often only have a 35 x 70mm rafter every 600mm vs a 50 x 75mm rafter every 400mm or so for the traditional roofs, so there obviously must be a fair degree of additional loading capacity on the 50mm rafters.

So we work to the schuco mounting kit spacings, but use 80mm bolts as opposed to the 60mm bolts BRE tested, so we should have a 1/3 higher pull out value. Essentially that works out at 800-1200mm spacings, with the brackets zig zagged up the roof, so that 2 out of every 3 rafters minimum are mounted to on each span.

On 35/38mm trussed roofs we mount to every second rafter, but double the rafters up as our SE reckon's they're generally not up to it even if you were to mount to every rafter as they're built to much tighter tolerances already.