Domestic solar PV quotes 2018

eamon_l · 29-01-2020 6:34pm

So I have been running an east/west split 4.2kW system for 20 days. Total produced is 17kWh with an average of 1.3-1.5kWh average daily. How does this stack up against other systems or peoples experience.

I know that my system is unevenly split across two string (10/4 with 7 panels on each string) and shading on certain panels is an issue.

Has anyone retrospectively installed optimisers and if so have they improved output significantly? Any advice welcom.

Zardaz · 29-01-2020 7:04pm

eamon_l wrote: »

So I have been running an east/west split 4.2kW system for 20 days. Total produced is 17kWh with an average of 1.3-1.5kWh average daily. How does this stack up against other systems or peoples experience.

I know that my system is unevenly split across two string (10/4 with 7 panels on each string) and shading on certain panels is an issue.

Has anyone retrospectively installed optimisers and if so have they improved output significantly? Any advice welcom.

That sounds a bit low, even for January.
17KWh/20 days is actually significantly less than a KWh per day average.

The East and West Arrays have to be on separate strings. Otherwise, for each string, the dark panels on one roof will kill the power from the bright panels on the other roof
If it's a decent dual MPPT inverter, you don't have to have the same number of panels on each string. Keep evenly illuminated panels on each string instead. (i.e. each roof on a separate string)

championc · 29-01-2020 8:35pm

eamon_l wrote: »

So I have been running an east/west split 4.2kW system for 20 days. Total produced is 17kWh with an average of 1.3-1.5kWh average daily. How does this stack up against other systems or peoples experience.

I know that my system is unevenly split across two string (10/4 with 7 panels on each string) and shading on certain panels is an issue.

Has anyone retrospectively installed optimisers and if so have they improved output significantly? Any advice welcom.

That sounds very poor. My 2.7kw system, albeit directly South facing, produced 4.57kw today. My roof slope is quite shallow, at only around 22° too. Google search for info on Tigo TS4-R-O's. It will highlight your issue of combining panels from shaded strings onto non-shaded. You'll find YouTube videos as well as written articles. Whether they work or not is a different matter.

However, your setup would appear to indicate that at least 7 panels are surely on the same side and on the same string, and on that basis, it's very much down to the weather of the day.

To spot any issues, you need to be looking at your data. People have a misconception that once there's daylight, you're getting loads of power - you're not. On a drizzly or cloudy day, you'll barely get 100w.

Here's a link to my live data. Note the output recorded at Sunrise and Sunset - not only feck all, but feck all for the half hour after sunrise and before sunset.

https://www.solarmanpv.com/portal/Terminal/TerminalMain.aspx?pid=95390

unkel · 30-01-2020 1:28am

eamon_l wrote: »

I know that my system is unevenly split across two string (10/4 with 7 panels on each string) and shading on certain panels is an issue.

What? you have 10 panels facing one side and 4 facing the other side and you have 3 of the 10 panels on the same string as the 4 panels on the other side?

What clown set that up for you?

You should have the 10 on one string and the other 4 on another string

Zenith74 · 30-01-2020 4:09am

eamon_l wrote: »

So I have been running an east/west split 4.2kW system for 20 days. Total produced is 17kWh with an average of 1.3-1.5kWh average daily. How does this stack up against other systems or peoples experience.

I know that my system is unevenly split across two string (10/4 with 7 panels on each string) and shading on certain panels is an issue.

Has anyone retrospectively installed optimisers and if so have they improved output significantly? Any advice welcom.

4.8kW E/W system (7 panels on each roof and string, no shading) has done 3kWh on each of the last four days (26th/27th/28th/29th). 34kWh total since it went live 12 days ago. North Dublin.

eamon_l · 30-01-2020 9:55am

unkel wrote: »

What? you have 10 panels facing one side and 4 facing the other side and you have 3 of the 10 panels on the same string as the 4 panels on the other side?

What clown set that up for you?

You should have the 10 on one string and the other 4 on another string

I have sent a further email to the installer to come back with proposals to fix my setup. If i do not get a response soon I will name and shame the company on this forum and contact the SEAI to lodge a formal complaint. I am also considering legal actions but that will be a last resort. They were more interested in selling me the extra panels than configuring the system so it performed in an optimal way. I'm not happy!!

Zenith74 · 30-01-2020 10:03am

eamon_l wrote: »

I have sent a further email to the installer to come back with proposals to fix my setup. If i do not get a response soon I will name and shame the company on this forum and contact the SEAI to lodge a formal complaint. I am also considering legal actions but that will be a last resort. They were more interested in selling me the extra panels than configuring the system so it performed in an optimal way. I'm not happy!!

It seems like the Installer was very much in-breach of the requirements of the SEAI scheme (excerpt below). Did you get a spec/contract from them before agreeing to proceed with the work and did it give detail of the design? I can imagine the SEAI taking issue with the work done and taking the company off the list of registered installers, but if you agreed to a contract I suspect legal action could be difficult enough.

The shading would be difficult to overcome without swapping out your inverter for microinverters, which would be a bit of work, though I'm sure they could use that inverter elsewhere. But that crazy split of the panels should be very easily sorted I'd have thought?

The Installer must use due care and attention to design a suitable, and optimum, solar PV system (and storage system, if included) for the homeowner, considering;
- The orientation of the building, pitch of the roof, any local shading effects from trees, vegetation, adjacent structures.
- The solar PV module array must be installed where minimal shading may be encountered for the building/site. Where shading is likely to be encountered consideration should be given to micro-inverters or optimisers to minimise the energy performance effect from shading.
- Maximising the energy yield (kWh/kWp) of the solar PV system.
- Maximising the homeowners’ likely self-consumption of generated solar electricity, either through appropriate sizing of the solar PV system, or additional storage solutions.

Mickeroo · 30-01-2020 10:13am

mickdw wrote: »

Who are the best companies to deal with for solar PV for a new build to work with builder and electrician on site?
Based in Mayo

Would also be interested in hearing about installers in the Mayo area if anyone is sending around PMs.

championc · 30-01-2020 11:32am

I cannot stress how important DATA is. You should get to know your system, as to what it's potential is, and then measure how it appears to perform against it's potential.

Over the last 4 days, my 2.7kw system has produced 1.59, 4.29, 4.1 and 4.57. Given my low roof slope angle, my max generation at high noon (around 12:35) is about 1.4kw. The sun angle is currently only 18 deg. A month ago, I wasn't even getting 1kw since the sun angle was only at 13 deg. It will be interesting to see as to what angle suddenly produces the optimum output.

So for comparison, my last 12 days total appears to be around 39.5kw

old_house · 30-01-2020 11:34am

I just received a first quote for a planned installation of a PV system in the course of a total renovation of a late 1950s detached house in the southwest. The house is going to have a (groundsource) heatpump as well as mechanical ventilation, so I assume the base load to be rather high. We further plan to buy an electric car at some point in the future, any reserves in terms of power generation will therefore be helpful going forward.

We have a large(ish) southwest facing pitched roof with a little shading at the lowest part, which only occurs between early November and late January. The angle of the roof is somewhere between 38 and 40 degrees. This roof faces towards the back garden and is not visible from the street. Sizewise we can accommodate 20 panels (4 rows of 5 panels in a landscape orientation) or maybe even 21 (2 rows of 8 panels each in portrait orientation and an additional row of 5 panels below), the available clear area of the roof is roughly 8.90m wide by 4.5m high. It's probably easiest to go with 20 panels, so we should max out at 6kWp. We applied for (and were granted) planning permission to install PV panels of the "maximum possible size".

I received 2 quotes for the planned installation, one for a 6kWp system and one for a 4kWp system, both with battery storage.

6KWp photovoltaic system with 6.3KWh battery storage: €14,785
4KWp photovoltaic system with 4.5KWh battery storage: €11,350
Solar iboost + diverter: €480 extra

Quote includes full supply, installation and commissioning of above systems, price is before any grants and excluding vat @13.5%

We will spend some time at home during daylight hours, so we could make good use of sunny periods by switching on devices like the washing machine or the dishwasher. That together with the upcoming FIT makes a large battery seem unnecessary, a small one might be cheap enough to consider due to the increased grant. But even taking the battery into account the quotes seem on the high side. Thanks for any opinions.

KCross · 30-01-2020 11:58am

old_house wrote: »

6KWp photovoltaic system with 6.3KWh battery storage: €14,785
4KWp photovoltaic system with 4.5KWh battery storage: €11,350
Solar iboost + diverter: €480 extra

Quote includes full supply, installation and commissioning of above systems, price is before any grants and excluding vat @13.5%

Adding the VAT on, this leaves you with a nett cost of €9882 for the 4kWp system after grant.

Way too expensive! Keep looking!

unkel · 30-01-2020 12:17pm

Those quotes sound almost as expensive as the ones you would expect from a active company with an "8" in its name

wexfordman2 · 30-01-2020 12:37pm

KCross wrote: »

Adding the VAT on, this leaves you with a nett cost of €9882 for the 4kWp system after grant.

Way too expensive! Keep looking!

Might I have this wrong, but does the vat rate of 13.5% not tell us something ?

13.5% is the vat rate for labour, and i think can be levied when the labour charge consists ifnthe majority ofnthe overall cost ? Ie, the charge for labour is higher than the charge for materials ?

I might be way off on this?

Zardaz · 30-01-2020 1:02pm

wexfordman2 wrote: »

Might I have this wrong, but does the vat rate of 13.5% not tell us something ?

13.5% is the vat rate for labour, and i think can be levied when the labour charge consists ifnthe majority ofnthe overall cost ? Ie, the charge for labour is higher than the charge for materials ?

I might be way off on this?

Its the "two thirds rule"
If a "job" consists of materials and labour, and if the materials consist of 2/3 or less of the total cost, then a vat rate of 13.5% can be applied to the entire bill.

Normally materials would be charged at 23% "on their own".
Given that the materials cost of a solar installation costs (say) 2-6 grand, this reduction in vat is worth 9.5% of that or up to ~€500 or so.
If you go the DIY route , the parts supplier will have to charge you (as a Joe Consumer) the full, higher vat rate. (and normally no trade discount either)

garo · 30-01-2020 1:33pm

old_house wrote: »

I

I received 2 quotes for the planned installation, one for a 6kWp system and one for a 4kWp system, both with battery storage.

6KWp photovoltaic system with 6.3KWh battery storage: €14,785
4KWp photovoltaic system with 4.5KWh battery storage: €11,350
Solar iboost + diverter: €480 extra

Quote includes full supply, installation and commissioning of above systems, price is before any grants and excluding vat @13.5%

Quotes are way too expensive. I would be looking at the 6kWp system for the price you have been quoted for the 4kWp system. Given that you are getting an ASHP I don’t see much point of getting an iBoost. Get a large hot water cylinder and you should be fine. And you are right about a smaller battery. A 3.5kWh battery could save you 1k over a 4.5kWh one and 3k over the larger one.

garo · 30-01-2020 1:41pm

championc wrote: »

I cannot stress how important DATA is. You should get to know your system, as to what it's potential is, and then measure how it appears to perform against it's potential.

Over the last 4 days, my 2.7kw system has produced 1.59, 4.29, 4.1 and 4.57. Given my low roof slope angle, my max generation at high noon (around 12:35) is about 1.4kw. The sun angle is currently only 18 deg. A month ago, I wasn't even getting 1kw since the sun angle was only at 13 deg. It will be interesting to see as to what angle suddenly produces the optimum output.

So for comparison, my last 12 days total appears to be around 39.5kw

The statement about data is very true. The optimal tilt angle depends on orientation. For a south facing array in Dublin 40-45 is best and for a E/W facing one 36 is best according to PVGIS. You will find max production in May and June. My E/W 4.8kWp system with a 24 degree title has produced 2.9, 3.3, 3.3 and 4.1. But I have a bit of shading from Nov-Jan from the southerly neighbour.

old_house · 30-01-2020 3:58pm

Thanks a lot so far, I will certainly keep looking for a better offer and also go for a smaller battery.

garo wrote: »

Given that you are getting an ASHP I don’t see much point of getting an iBoost.

My thinking on the diverter was that the excess electricity would mainly be availabe in summer when the heatpump is not running. So the immersion might not be as efficient, but it saves you from cycling the heatpump just for the water and by doing so prolongs the life of the compressor. And efficiency is pretty much irrelevant since the energy could not be used otherwise anyway...

garo · 30-01-2020 6:04pm

That is a very valid point. Make sure you get a large enough cylinder that you can get by on a cloudy day or two. You will find you produce more than enough in he peak summer months on a sunny day so if followed by a cloudy one you have enough hot water.

Buddha Breath · 31-01-2020 5:49pm

Hi all, first off, thanks for contributing so much knowledge to this post – It’s taken me a few days but have finally waded through the 160 pages! I have a few questions if you don’t mind…..

House and usage details are:

North Sligo, 2007 built bungalow with 40 degree pitch slate roof, S,E and W orientations available
South facing roof - max space for 14 panels
East and West facing roofs - max space for 6 panels each orientation
Annual electricity usage approx. 5500 kWh
Working from home most days so should be able to make good use of this
No EV (yet)
No night rate
Non condensing oil boiler (not zoned) used for heating and water in winter but mainly use a Willis immersion heater in summer
Triple glazing, some airtightness and extra insulation added recently

I’m trying to figure out the best setup based on my available orientations, possibly combining S, E and W. I’d be looking to get a 4-6 kWp setup with 5 kW dual MPPT hybrid inverter and 2.4kW battery. I’m undecided about the diverter for now. I may need optimisers for 2 of my South facing panels (where a second roof joins the main roof). Would the inverter be able to handle an SEW combination or would it make more sense to add a second (smaller) inverter?

The first quote I've received works out around 6.5k net for a 4.4kWp setup with hybrid inverter and 2.4Kw battery installed - south facing only (including 2 optimisers)

Thanks

championc · 31-01-2020 7:18pm

Buddha Breath wrote: »

Hi all, first off, thanks for contributing so much knowledge to this post – It’s taken me a few days but have finally waded through the 160 pages! I have a few questions if you don’t mind…..

House and usage details are:

North Sligo, 2007 built bungalow with 40 degree pitch slate roof, S,E and W orientations available
South facing roof - max space for 14 panels
East and West facing roofs - max space for 6 panels each orientation
Annual electricity usage approx. 5500 kWh
Working from home most days so should be able to make good use of this
No EV (yet)
No night rate
Non condensing oil boiler (not zoned) used for heating and water in winter but mainly use a Willis immersion heater in summer
Triple glazing, some airtightness and extra insulation added recently

I’m trying to figure out the best setup based on my available orientations, possibly combining S, E and W. I’d be looking to get a 4-6 kWp setup with 5 kW dual MPPT hybrid inverter and 2.4kW battery. I’m undecided about the diverter for now. I may need optimisers for 2 of my South facing panels (where a second roof joins the main roof). Would the inverter be able to handle an SEW combination or would it make more sense to add a second (smaller) inverter?

The first quote I've received works out around 6.5k net for a 4.4kWp setup with hybrid inverter and 2.4Kw battery installed - south facing only (including 2 optimisers)

Thanks

You will get so much power from the 14 panels all on the south roof, you won't need an inverter supporting two strings. East and West should only be considered if you have no option for southerly orientated panels. With 40 deg roof, you'll get a massiveamount of power , even in winter sunshine, at that angle.

Maybe someone else on here can provide a live link to their system

My system - 2.7kw, 22deg roof, South facing
https://www.solarmanpv.com/portal/Terminal/TerminalMain.aspx?pid=95390

garo · 31-01-2020 7:50pm

Have a look at the spreadsheet on this page to give you an example of how much output you will get. https://aces.nmsu.edu/pubs/_circulars/CR674/
It only works for US longitudes so you’ll have to choose something like 82W to get the hours right. 40 degrees is a good slope. Your south facing panels will perform really well for the winter and you will have excess power in the summer but you won’t be able to take as much advantage of the long evenings. If the cost is similar (and it probably won’t be) a 5+5+5 would enable you to utilise the energy a lot better. And avoid shading. Otherwise 8+6 with 6 going to W is also an option. People generally use more electricity in the evening than morning.
Also if you heat the water with an immersion in the summer a diverter makes sense. Make sure you either have a large cylinder or a mixing anti-scalding valve installed that will allow you to make full use of the extra summer sun.

Mickeroo · 31-01-2020 8:07pm

unkel wrote: »

12m2 or no more than 7 panels

But it is very unlikely you will be old to take the panels down if you put up more without planning permission, even if you put them on the front (road facing) roof of your house as per a recent well published court case

Just on this, how common is it for the reputable installers to be willing to plough ahead on a bigger array without planning?

I've no idea what dimensions the roof is so not sure I can even fit above the maximum. The back of the house is south facing(well very slightly sw) and all that's behind us is a field and then behind that a park so I think I'd be unlikely to have issues either getting planning or skipping it.

KCross · 31-01-2020 8:45pm

Any comment on whether a Solis or SMA inverter is better?... standard inverters, not hybrid.

SMA is quoting several hundred more expensive. Seems alot since a standard inverter isnt much to begin with. Is SMA the Rolls Royce of inverters?

unkel · 31-01-2020 8:45pm

Buddha Breath wrote: »

South facing roof - max space for 14 panels
East and West facing roofs - max space for 6 panels each orientation

If you're going ahead anyway with a grant install using the max subsidy (4kwp), it is very little extra work / money to install more panels, so if I were you, I'd use all of it. 26 panels. And use a 6kW inverter (the max allowed). All depending of course on how good a deal you can negotiate for the extra panels

We are likely to get a feed in tariff in the next few years, but if you reckon that's a long time away or might never happen, it would be worth considering an immersion diverter on such a big system with in your case only expensive alternative ways of heating water (with electricity or with an inefficient oil boiler)

Mickeroo wrote: »

Just on this, how common is it for the reputable installers to be willing to plough ahead on a bigger array without planning?

I'd say they don't even ask. Otherwise they'd never install more than 2kwp

unkel · 31-01-2020 8:47pm

KCross wrote: »

Any comment on whether a Solis or SMA inverter is better?... standard inverters, not hybrid.

SMA is quoting several hundred more expensive. Seems alot since a standard inverter isnt much to begin with. Is SMA the Rolls Royce of inverters?

SMA have been around for a very long time and they do have a good reputation. That said, if both end up lasting say 10-12 years without fault, it will have taken you at least 1, maybe 2 years extra for the SMA system to have paid back for itself, something that from your previous posts you seem to find very important when making decisions before deciding what to get. This is no accusation or anything, I'm the same myself as you know

Buddha Breath · 31-01-2020 9:44pm

Buddha Breath wrote: »

The first quote I've received works out around 6.5k net for a 4.4kWp setup with hybrid inverter and 2.4Kw battery installed - south facing only (including 2 optimisers)

Thanks

Thanks for the replies guys. Any thoughts on the quote above?

unkel · 31-01-2020 10:03pm

Buddha Breath wrote: »

Thanks for the replies guys. Any thoughts on the quote above?

Quote is alright. If finalising the deal I'd try and negotiate the immersion diverter into that price. And see what deal they do for more more panels.

wexfordman2 · 31-01-2020 10:16pm

unkel wrote: »

If you're going ahead anyway with a grant install using the max subsidy (4kwp), it is very little extra work / money to install more panels, so if I were you, I'd use all of it. 26 panels. And use a 6kW inverter (the max allowed). All depending of course on how good a deal you can negotiate for the extra panels

We are likely to get a feed in tariff in the next few years, but if you reckon that's a long time away or might never happen, it would be worth considering an immersion diverter on such a big system with in your case only expensive alternative ways of heating water (with electricity or with an inefficient oil boiler)

I'd say they don't even ask. Otherwise they'd never install more than 2kwp

Is 26 panels not nearly 8kwp ? Is there not a risk of it overloading the 6kw inverter ? I seem to remember there is a risk of the voltage being too high going in to an inverter if you oversize the panels ?

Shefwedfan · 31-01-2020 10:30pm

I just got install and the max allowed was 19 panels. I could of put 100 up on the roof but not allowed over 19. The panels are 310w Q-Cells.....

Buddha Breath · 31-01-2020 10:36pm

garo wrote: »

If the cost is similar (and it probably won’t be) a 5+5+5 would enable you to utilise the energy a lot better. And avoid shading. Otherwise 8+6 with 6 going to W is also an option.

Thanks Garo. Do you think the inverter setup would be more complicated with 3 strings, or could you put two in parallel on one string and one on the other? Would you need many additional optimisers?

Domestic solar PV quotes 2018

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