Solar Panel Guide Discussion

Martyn1981

maravesi wrote: »

hi tunnel

thanks for the advice. yes, i think solaredge might be a good idea having read up a bit. Unfortunately it's 22deg to east, so ENE side roof would that mean it's not worthwhile using the side? I did ask the guy who came around and he said given we use very little there is no point...but a bigger system is cheaper by the unit than a smaller one so i think should be a better investment...

Quick numbers, all 1kWp, but based on 35d pitch, and roof pitch is important for north rooves:

-22 (SSE) 984kWh pa
-112 (ENE) 702
+158 NNW) 554

Most of the income will come from FiT and export, not leccy savings, so it's best to go bigger, if you can.

Total guess, but a 2 roof, 4kWp, SolarEdge (SE) system with Panasonics, (if they all fit) might cost £1k to £1.5k more (more expensive panels, a little more for scaffolding, and perhaps £300 more for the SE kit).

A good deal for a 'normal' install would be around £5k, so, perhaps £6k to £6.5k.

Perhaps 3 roof install, normal panels, SE kit and extra scaffolding ..... £600 more than 'normal' ????????

Mart.

oldskoo1

Hi tunnel my roof is 198c orientation so very slightly ssw

I didn't realise they could move them once they are fixed on there.

I know I'm probably obsessive about this and I've been told the difference is negligible but whilst the scaffolding is up I know if I don't ask and check all options I will regret it

Martyn1981

maravesi wrote: »

Hi Mart

Thanks! Roofs are the other way around - SSE and ENE (if abbreviations are wrong - the front is 22deg to the east so side is 22 deg to north).

I'll have a look at the links you've sent many thanks! Did you fit your own? I'm just thinking you are based in Cardiff -perhaps if you used a specific company they might be able to do Bristol too. Any recommendations?

My ESE was fitted by a large electrical company in Newport, who've since gone bust! My WNW system was fitted by a SolarEdge specialist (not many back in 2012) from Rochdale.

Just had another thought, fancy triangular panels?

Take a look at these, they cost aprox the same per Wp as the Panasonic 240's. They aren't as efficient, so will need more space, but they gain the space by filling in the triangles in a hipped roof install:

Panasonics

Trienergia

Mart.

tunnel

oldskoo1 wrote: »

Hi tunnel my roof is 198c orientation so very slightly ssw

I didn't realise they could move them once they are fixed on there.

I know I'm probably obsessive about this and I've been told the difference is negligible but whilst the scaffolding is up I know if I don't ask and check all options I will regret it

They can't move them,they would have to remove them and place the fixings lower down the roof then re fix the panels. Did you ask for the panels to be fixed so high up?

maravesi

oh wow! didn't even know there are triangular ones. would be a good "top-up".

I am getting very muddled up here. Am i getting this right - a 4kWp 2-roof system would be best option(if it fits?!). If we can fit 6x250W on each one it will be 3kWp, but we could get higher output panels to enhance the system to closer to 4kWp with either panasonics being smaller or higher output panels at 300/330W. A 3-roof is also a possibility although I'm looking at approx 50% output from the NNW roof as opposed to almost 100% at the front and 70ish%at the side. But 1kWp would fit on each roof.

The more options i have the more confusing it gets!

What would you do if you had my house? And how do i find a good installer who would do decent quality/price panels in my area?

Seems panasonics are just a bit too pricey - is the quality worth the extra cost? what abot Sharp/Enhance/other ones?

I am sorry for asking a million questions. I don't want to waste your time which you so kindly spend on providing valuable advice to so many of us...It just seems like the more answers i have the harder it gets to decide!

maravesi

I've just had a thought - would it be best to buy the panels separately and pay for the installation or get quotes for the whole thing inc panels etc?

oldskoo1

tunnel wrote: »

They can't move them,they would have to remove them and place the fixings lower down the roof then re fix the panels. Did you ask for the panels to be fixed so high up?

I asked if there is enough room for a 3rd row to not centre them on the roof

When we discussed it it sounded like it would be just level with the bottom of chimney. But didn't realise so close

I'm not concerned about the long early am shade as moving down just produces more panels in strong late pm shade.

My only concern was a more permanent blocking of light on the top right panel due to the chimney

As pointed out it appears to be a reflection. But just also checking it isn't acting as a diffuser permanently. And what happens in winter

EricMears

maravesi wrote: »

I've just had a thought - would it be best to buy the panels separately and pay for the installation or get quotes for the whole thing inc panels etc?

Under the 'usual FIT scheme' , VAT is charged at 5%If you were to buy your own panels outside a supply & fix contact from a registered contractor, you'd have to pay 20% VAT on them. Fitting them yourself or by a contractor not registered for the scheme would disqualify you from FIT payments and probably have you paying 20% VAT on fitting charges..

Martyn1981

maravesi wrote: »

The more options i have the more confusing it gets!

It just seems like the more answers i have the harder it gets to decide!

Apologies for that, I'm guilty of doing this. Try to suggest as many ideas/solutions as possible, but it's an awful lot to take in at first. I promise it all gets easier as it slowly sinks in. All of your questions and thoughts so far, seem to suggest that you do 'get it'. Well done. :T

maravesi wrote: »

oh wow! didn't even know there are triangular ones. would be a good "top-up".

Yes. But just in case you've misunderstood, they aren't really a top up, the triangles and squares come as a set (so to speak) with dimensions to match each other (not normal 1.6m by 1m panels). They have the same efficiency as normal panels, but squeeze more Wp onto a hipped roof by filling more of it. Probably look better too.

maravesi wrote: »

Seems panasonics are just a bit too pricey - is the quality worth the extra cost? what abot Sharp/Enhance/other ones?

The 240Wp Panasonics cost more because they are higher efficiency panels. Don't get confused, they'd generate the same as a normal efficiency 240Wp panel, it's just that they do it with a smaller footprint. They are only 800mm wide compared to a more normal 1,000mm. So you pay extra to squeeze more Wp into a given space.

I always run away from questions about which panels are best. No idea!

maravesi wrote: »

I am getting very muddled up here. Am i getting this right -

a 4kWp 2-roof system would be best option(if it fits?!). Yes.

If we can fit 6x250W on each one it will be 3kWp, Yes.

but we could get higher output panels to enhance the system to closer to 4kWp with either panasonics being smaller or higher output panels at 300/330W. Yes.

A 3-roof is also a possibility although I'm looking at approx 50% output from the NNW roof as opposed to almost 100% at the front and 70ish%at the side. Yes.

But 1kWp would fit on each roof. No. (unless you mean 'at least'). At a very rough guess, and the info you've given so far, it sounds like 1.5kWp would fit on each roof using 'normal' 250Wp panels. More if using physically smaller (higher efficiency) 240Wp Panasonics, or filling the triangular rooves out using normal efficiency (but not cheap) triangular + square panels.

maravesi wrote: »

What would you do if you had my house? And how do i find a good installer who would do decent quality/price panels in my area?

Personally, so long as you don't quote me, or hold me to this, I'd probably just use the two easier rooves, placing 1.5kWp of 6 regular panels on each, if they fit. I'd be tempted to use a regular inverter*, but it has to be dual/twin MPPT, this type of inverter would treat each roof as a separate system - very common, nothing special.

*But, I'd be a little concerned about chimney shading, and would want to move that soil pipe, or cut it shorter and place a special valve on top [air admittance valve, that allows air in, but prevents smells leaving]. Otherwise, I'd go with a SolarEdge inverter and power optimisers.

From that base, I'd then price up, just in case, the difference if using Panasonics or the triangles to see how the extra income works out against the extra cost.

maravesi wrote: »

I am sorry for asking a million questions. I don't want to waste your time which you so kindly spend on providing valuable advice to so many of us...

Not a problem, it's nice to solve puzzles, share knowledge, and test out the grey matter. Also, hopefully, other folk who don't want to post/ask will read these discussions and get answers or suggestions.

Mart.

maravesi

Thanks Mart and I promise not to hold you up to your choice - it makes it easier to have someone who knows what they are talking about and whose commission doesn't depend on selling me an expensive system to give me a starting point.

Yes, i did get that the triangular/squares come together. I managed to draw up a picture for the front which fits 1.7kW of those. And yeah, i meant at least 1 kWp would fit on each roof i.e. without having to work extra hard to make more fit every which way. Thanks for the clarifications.

At 5pm today i had a look at the front and the shade from the chimney is very long- all the way across the roof. it probably takes up 20% of the roof. So then i had a look at the back and side. The side was shady, but the back was lit-up. SO that makes me think that doing three rooves would give me an even throughout-the-day generation which would be good and that could be done with cheap rectangular panels.

I'm starting to think that using the back wouldn't be a terrible idea...

Just FYI the front pitch is 38 degrees. The back must be the same. Don't know about the side, but I will try to work it out if I can. The side is an equilateral triangle with sides of 6m. 4 regular sized panels will fit. maybe 5, but i think 6 wouldn't.

The pipe is not an issue as it almost faces north and the sun is never behind it so it doesn't cast a shadow over the roof unless it was a different issue with it being there that you had in mind.

The puzzle is slowly starting to fit together in my head.

I should try to work out how many rectangles vs squares/triangles I can fit on the side.

So 6x250 at front and side gives me approx 2.475kW actual output (going on 95% at front and 70%side). With 4 at the back that is a 4kWp system, but actual output would be more like 3. Plus i probably can't squeeze 6 on the side.

could do 6/5/4 That would take me to almost 4kWp and approx 2.8kW. or 6/4/4. Or as you say just do front and side with whatever panels i can fit the most Wps of.

OK going in a circle again. I'll sit down with a few pieces of paper!