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  • FIRST POST
    • Zarch
    • By Zarch 13th Jun 18, 10:05 PM
    • 154Posts
    • 364Thanks
    Zarch
    Quotes and install questions
    • #1
    • 13th Jun 18, 10:05 PM
    Quotes and install questions 13th Jun 18 at 10:05 PM
    Hi all,

    Three potential locations on the property in Sheffield.
    • Main Roof (maybe 9 panels, 2.7kWp) SW Facing - PVGIS approx 2500kWh
    • Dormer Flat Roof (4 panels, 1.2kWp) - SW Facing (flat) - PVGIS approx 940kWh
    • Rear Extension (3 panels, 900kWp) - E Facing - PVGIS approx 770kWh (gets sun from sunrise, but has shade issues from noon onwards)

    Wife isn't happy about using the dormer as the builders (4 years ago) said the vinyl roof will eventually need replacing.

    After weeks of reading forums etc i'm pretty happy with all the FIT and savings figures i've pulled together. I think I understand them all.

    I've been monitoring my own usage for the last month via an old Current Cost usage meter into a Raspberry PI running measure it and then uploading to PVOutput.

    ** I can post my PVOutput url, not enough posts **

    Electricity bills also confirm approx 3700kWh per year usage.

    Quotes so far
    1. Ikea via Solarcentury - 13 panels 5,600
    2. 'South' installer - 11 x 300w = 3.3kWp (5,200), 11 x 320w = 3.5kWp (5300) Solaredge inverter
    3. 'North' installer (Bisol panels)
    Main roof and Rear Extension (12 panels x 300w = 3.6kWp) - 5470 (plus power optimisers for shade)
    Main roof and Dormer (13 panels x 300w = 3.9kWp) - 5300
    All three locations (16 x 300w = 4.8kWp) - 6350 - quote says permission required

    4. 'Local' installer - hopefully coming next week.

    1. Don't think I will be going any further with Ikea from comments i've read.
    2. This quote is via emails, photos and google maps. No site survey yet, so discussions are on-going.
    3. Again, this from photos and emails etc. They've also gone to the trouble of checking the building plans for the dormer for the flat roof weight bearing.

    Would I be right in thinking both these quotes on the high side? I've seen 4k upwards on here for up to 4kWp systems.

    Both quotes have come back with around 10-11 year break even calculations.
    Which sort of ties in with the spreadsheets i've pulled together using PVGIS/FIT/energy saving etc.

    I think whether the system costs 4k or 5k/6k, it just seems to add a few years to breaking even. Obviously, the cheaper the better.

    Are these private installers open to negotiation? Are these first quotes ripe for discussion?

    Any thoughts on any of the above?

    Cheers.
    Last edited by Zarch; 13-06-2018 at 10:07 PM.
Page 3
    • Coastalwatch
    • By Coastalwatch 8th Aug 18, 11:19 AM
    • 350 Posts
    • 1,395 Thanks
    Coastalwatch
    Can't believe i've not asked this before, but what generation can you expect from panels in full shade?

    These East-ish facing 300w panels i'm hoping to put in will be in full shade from 2pm onwards. So it could still be a bright summers day everywhere else.

    What performance do you get in full shade during the day? Good, bad of indifferent?
    Originally posted by Zarch

    I've two panels vertically mounted on the WSW gable end so in full shade until around 1pm. The remainder are SSE at 23 degree pitch in full sun all day. Generally the two end panels generate between 30 & 50% in comparison depending upon the day. As I'm typing this at 11.20 am they are at 20%, but it was a cloudy start to the day!
    East coast, lat 51.97. 8.26kw SSE, 23 pitch + 0.59kw WSW vertical. Nissan Leaf plus one dirty diesel. Still waiting for V2H and home storage to become available at sensible cost.
    • Martyn1981
    • By Martyn1981 8th Aug 18, 11:21 AM
    • 7,839 Posts
    • 12,466 Thanks
    Martyn1981
    Can't believe i've not asked this before, but what generation can you expect from panels in full shade?

    These East-ish facing 300w panels i'm hoping to put in will be in full shade from 2pm onwards. So it could still be a bright summers day everywhere else.

    What performance do you get in full shade during the day? Good, bad of indifferent?
    Originally posted by Zarch
    East and 2pm takes the pressure off. They will lose some gen especially in the summer, but will be losing power anyway from 2pm onwards.

    On a perfectly clear blue sky (very, very rare) my west panels generate almost nothing in the morning, and my east panels next to nothing in the evening, whereas with a little bit of white, the light still gets reflected back down, which shade won't affect.

    No escaping the fact you will lose some gen especially from 2pm to 4pm, but not too big a worry. If they were west facing panels, then it would be a disaster.
    Mart. Cardiff. 5.58 kWp PV systems (3.58 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
    • JKenH
    • By JKenH 8th Aug 18, 7:29 PM
    • 222 Posts
    • 943 Thanks
    JKenH

    On a perfectly clear blue sky (very, very rare) my west panels generate almost nothing in the morning, and my east panels next to nothing in the evening, whereas with a little bit of white, the light still gets reflected back down, which shade won't affect.
    Originally posted by Martyn1981
    Ah, that probably explains why a couple of days ago with my East and West facing roofs I had disappointing overall power from a crystal clear sky. Peak PV was just over 4 kw compared to over 5kw today with some cloud about.
    Lincolnshire. 7.8 kWp system, (4.2 kw west facing panels , 3.6 kw east facing), Solis inverters, IBoost water heater.
    • Zarch
    • By Zarch 22nd Aug 18, 9:10 AM
    • 154 Posts
    • 364 Thanks
    Zarch
    Almost ready to hit 'buy' from CTS. Almost certainly going to go with 17 x 300w (5.1kWh) rather than 17 x 320w (5.44kWh). Cannot justify the extra 700 as discussed previously.

    They've said the DNO application/approval will be zero cost which is nice. Although we've still not heard back from the DNO application and that has been with them a month now...... they turn the applications round in 'up-to' 45 days, so they've jut 2 weeks left.

    If DNO approval comes through we are sticking with the 5000kWh inverter. Nothing much to be gained from dropping to 3680 CTS say and they'd recommend the 5000 model. Obviously, DNO rejection could change this.

    I noticed there is a 45 wi-fi module required for the Solar Edge inverter if you can't run ethernet to where your inverter is. Luckily i've got a spare powerline adapter and i'll just run that into there and save the 50.

    So what is the delay you ask? Well my roofer can't come until October to repair/relay the roof on the dormer. And i'm not putting panels on there without it being in tip top shape and currently its showing its age.

    Running over into October means the FIT rates drop ever so slightly into the final quarter of the year, but its less than tenth of a penny, so would only be losing about 35 over 10 years.

    So the quote for the whole shanbang is 6400. I'm hoping this might reduce if we go into October and components drop in price.

    Maybe the 320w come down to viable price? Not holding my breath.

    I just want to get it all installed so I can start looking at daily graphs!!
    Last edited by Zarch; 22-08-2018 at 9:19 AM.
    • pinnks
    • By pinnks 22nd Aug 18, 8:35 PM
    • 666 Posts
    • 1,450 Thanks
    pinnks
    Good job! Hope the install goes well. I am sure you'll report back in due course...
    Wiltshire - 5.25kWp
    3.5kWp: 14 x Phono Solar 250 Onyx, Sunny Boy 4000TL, WSW 40 degrees, June 2013
    1.75kWp: 7 x Phono Solar 250 Onyx, Sunny Boy 1600TL, SSE 45 degrees, March 2014
    • JKenH
    • By JKenH 24th Aug 18, 7:33 PM
    • 222 Posts
    • 943 Thanks
    JKenH
    I have a 7.8kwp system with 4.2 kwp on the west facing (80* west of south) roof with a 39* pitch. The panels on that roof feed into a Sofar Solar 3680TLM inverter (3.68kw). I live in not so sunny north west Lincolnshire. Given our latitude, and the orientation and pitch of the roof is the inverter ever going to limit output from those panels? (I see that Pinnks has a 4000TL for his 3.5kwp array with a similar orientation and pitch.).

    I am suspecting not but would welcome the views of you technical guys on here.

    The 3.6kwp of panels on the east side of the roof (100*east of S), same pitch, have their own inverter.

    Out of interest can anyone speculate as to the peak kw I might see from my installation in ideal conditions. Best I have seen is 5.95kw.

    Thanks in anticipation.
    Lincolnshire. 7.8 kWp system, (4.2 kw west facing panels , 3.6 kw east facing), Solis inverters, IBoost water heater.
    • Coastalwatch
    • By Coastalwatch 24th Aug 18, 8:17 PM
    • 350 Posts
    • 1,395 Thanks
    Coastalwatch
    I have a 7.8kwp system with 4.2 kwp on the west facing (80* west of south) roof with a 39* pitch. The panels on that roof feed into a Sofar Solar 3680TLM inverter (3.68kw). I live in not so sunny north west Lincolnshire. Given our latitude, and the orientation and pitch of the roof is the inverter ever going to limit output from those panels? (I see that Pinnks has a 4000TL for his 3.5kwp array with a similar orientation and pitch.).

    I am suspecting not but would welcome the views of you technical guys on here.

    The 3.6kwp of panels on the east side of the roof (100*east of S), same pitch, have their own inverter.

    Out of interest can anyone speculate as to the peak kw I might see from my installation in ideal conditions. Best I have seen is 5.95kw.

    Thanks in anticipation.
    Originally posted by JKenH
    Hi Ken, I'm no expert but popping onto the pvgis website and plugging your figures in it suggests that the total losses in the PV array to be 23%. Thus removing this from your peak output of 4.2 kW leaves a figure of 3.2 kW. From this it would seem that your inverter is unlikely to limit output of your system.
    Applying these simple figures to the entire system then 7.8 kWp minus 23% returns 6.005 kWp.


    There may of course be other issues not shown here to take into account but from my simple view your max figure seems to confirm that all is in order. One other clue to all this would be the curve on your output graph. If you have a gentle curve all the way up and back down then peak would appear to be reached. If on the other hand the curve has a flat at peak output then your output could be limited by the Inverter.
    Happy to be proved otherwise!
    East coast, lat 51.97. 8.26kw SSE, 23 pitch + 0.59kw WSW vertical. Nissan Leaf plus one dirty diesel. Still waiting for V2H and home storage to become available at sensible cost.
    • JKenH
    • By JKenH 24th Aug 18, 8:55 PM
    • 222 Posts
    • 943 Thanks
    JKenH
    Hi Ken, I'm no expert but popping onto the pvgis website and plugging your figures in it suggests that the total losses in the PV array to be 23%. Thus removing this from your peak output of 4.2 kW leaves a figure of 3.2 kW. From this it would seem that your inverter is unlikely to limit output of your system.
    Applying these simple figures to the entire system then 7.8 kWp minus 23% returns 6.005 kWp.


    There may of course be other issues not shown here to take into account but from my simple view your max figure seems to confirm that all is in order. One other clue to all this would be the curve on your output graph. If you have a gentle curve all the way up and back down then peak would appear to be reached. If on the other hand the curve has a flat at peak output then your output could be limited by the Inverter.
    Happy to be proved otherwise!
    Originally posted by Coastalwatch
    Thanks for that. Sounds as though everything is hunky dory then. Is that 23% down on peak PV or would that be the shortfall over the year? I was only expecting to be about 10per cent down in the summer but more in the winter.
    Lincolnshire. 7.8 kWp system, (4.2 kw west facing panels , 3.6 kw east facing), Solis inverters, IBoost water heater.
    • Martyn1981
    • By Martyn1981 25th Aug 18, 7:41 AM
    • 7,839 Posts
    • 12,466 Thanks
    Martyn1981
    Ken, gut feeling for me, is that you are fine, very fine!

    There will be times, perhaps April & October when the sky is clear and temps are low that the 4.2kWp will max out, possibly even go 100%+, but these will be short times before the panels get hot. 90% is more likely the peak, so 3.78kW, but again not for significant periods, and the smaller inverter will be more efficient at lower generation times, so overall may be a better package than one closer to 4.2kW.

    You don't hear it so often now, but there used to be a rough guide that for the UK a 10%-20% undersized inverter would give you the most annual generation. It would depend on location and orientation, so south facing on the Cornish coast you might go with closer to 100%, but for off south orientations it's worth considering 'poor' weather generation for the UK, whereas you wouldn't bother for sunnier climes.

    Extrapolating from my system (5.58kWp), I see brief peaks of 5kW (when there are clouds or sun showers) and sustained gen of 4.2kW, these are summer figures when the sun can 'see' all the panels, so around 11am - 3pm. For you that would work out around 7kW and 5.87kW, which seem to fit with your experience and Coastalwatch's calcs.

    Looking good.
    Mart. Cardiff. 5.58 kWp PV systems (3.58 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
    • JKenH
    • By JKenH 25th Aug 18, 9:14 AM
    • 222 Posts
    • 943 Thanks
    JKenH
    Thanks Martyn, that is really interesting. I remember looking at the graphs for my best day so far, my one and only Hawaii which was in late July and saw peak PV was only about 4kw. It was a stinking hot day. Just recently when the sun has deigned to show its face I have seen peak figures regularly above 5kw.

    Hopefully on a cool day like today we should see something good. My day did not get off to a great start though as my system tripped out again, just as it had yesterday at 6.45 am. Foolishly after getting up at 6 I had gone back to bed and dozed off so hadn’t picked up on that until 7.45. When the panels got up to speed I saw 2.83 kw then it slipped back and is now climbing again. The sky is quite consistently clear so I was a bit puzzled by that peak - could it have been because the system had just woken up again? Optimum orientation for the panels on my east roof would probably be about 6am BST but of course the sun would be lower in the sky then. I am thinking that the sun will be at 90* to my panels at about 12.30. BST so my East facing panels should peak somewhere between those times.

    My west facing panels will pick up as the sun gets in the sky and mess my calculations up of course so I will just have to go in the loft and keep an eye on the inverters. Presumably as the day warms up performance will fall off as well.

    Do you fancy writing a programme, Martyn, so we can get our predicted PV by just entering our latitude, pitch, date, time of day air temp, and any other variables you can think of? Only joking but it would be fun and I suspect you are the man who could rise to such a challenge.
    Last edited by JKenH; 25-08-2018 at 9:21 AM.
    Lincolnshire. 7.8 kWp system, (4.2 kw west facing panels , 3.6 kw east facing), Solis inverters, IBoost water heater.
    • Zarch
    • By Zarch 25th Aug 18, 11:25 AM
    • 154 Posts
    • 364 Thanks
    Zarch
    Even though this conversation is taking my install thread off topic!!

    I can't help but get involved.

    How about this site?
    https://pvwatts.nrel.gov/index.php

    You can put a location in (not as exact as PVGIS as it seems primarily North America focused). But find somewhere reasonably local and you can then download a full year of hourly generation estimates in .csv format.

    Might be worth you guys who have some actual generation data to compare these estimates against.

    Have fun.
    • JKenH
    • By JKenH 25th Aug 18, 7:37 PM
    • 222 Posts
    • 943 Thanks
    JKenH
    Sorry Zarch for meandering off topic. That link was quite interesting and tallied with my PVGIS calcs.

    I have been monitoring my output today with a view to seeing what impact orientation has on output. Apart from the first couple of hours there has been a lot of cloud here today and I have had to take readings when the clouds permitted. These are clear sky figures for my output in kw at a moment in time on my east and west roofs.

    Time West East
    8.15 0.2 2.20
    9.27 0.2 2.28
    9.43 0.25 2.26
    10.25 0.75 2.30
    10.5 1.10 2.25
    12.04 2.56 2.22
    12.25 2.85 2.32
    14.13 3.69 1.43
    16.15 3.36 0.34
    16.40 3.05 0.28
    17.20 2.65 0.19
    18.00 2.27 0.18

    What I did find interesting was how the output from the east roof stayed very consistent during the morning as we moved away from optimum orientation to due south. The figures for the west roof didn’t hold up so well as we drifted from south to optimum orientation although they peaked higher and might have done even better with more readings either side of 2pm.

    What I did see though was we reached peak inverter output of 3.68 kv on the west roof with the pv steadily climbing over a couple of minutes as the cloud disappeared. Just as I thought we were going to sail past it the clouds came over again and stayed there for the next couple of hours. Shame I couldn’t get any figures for about 1pm or 3pm. On the raw Moixa data there was a combined peak of 5.41 at 13.19 which I missed while eating my lunch.

    What did surprise me was how much better the 14 panels on the west roof performed in terms of peak output compared to the 12 on the east roof. The west roof is 80*w of s and the east roof 100*e of s so I wasn’t expecting there to be that much difference.

    All the figures are direct from the inverters in the loft except the 8.15 reading which is taken as a combined figure from the Moixa dashboard with the split estimated.
    Last edited by JKenH; 25-08-2018 at 7:45 PM.
    Lincolnshire. 7.8 kWp system, (4.2 kw west facing panels , 3.6 kw east facing), Solis inverters, IBoost water heater.
    • Zarch
    • By Zarch 30th Aug 18, 10:31 AM
    • 154 Posts
    • 364 Thanks
    Zarch
    Bad news. CTS have had a call from Northern Power and there is indeed now a 350 charge for a G59 application. This was a shock to CTS as it appears other power providers are not charging. They put a request in to Western the other week with no problems.

    Ah well, back to the plan of the 3.68 inverter. As per the calcs and graphs this shouldn't be too much of a problem.
    • KevinG
    • By KevinG 31st Aug 18, 7:58 PM
    • 1,332 Posts
    • 3,513 Thanks
    KevinG
    Originally posted by Zarch
    That's interesting, I tried it and got a similar annual total to PVGIS (a bit less) but the monthly distribution was markedly different and more accurately reflected what I actually get.
    Baxi Ecogen 24/1.0 Micro-CHP boiler installed Oct-2010; 2kWp Solar PV - 10*200W Kioto, SMA Sunny Boy 2000HF, SSE facing, some shading in winter, 37 pitch, installed Jun-2011, inverter replaced Sep-2017.
    • Zarch
    • By Zarch 4th Sep 18, 10:56 AM
    • 154 Posts
    • 364 Thanks
    Zarch
    Woooo, things are getting closer. I have a date with my roofer for the Dormer re-roof for the middle of this month and i'm speaking to CTS to try and get in closely after to beat the end of Sept drop if FIT values. (only pennies I know, but every penny counts)

    Final quote from CTS: 17 x 300w (total 5.1 kWh) JA black panels (with PO built in) and a Solar Edge 3.68 inverter - 6259

    An EPC assessment that needs scheduling, then 4 days work for the main install (1 day scaffold, 2 day install, 1 day scaffold)

    The install is across 4 aspects / different roofs:
    3 panels (0.9 kWh) on the East-ish facing single storey extension (29 deg tilt)
    4 panels (1.2 kWh) on the south-west-ish facing flat dormer roof in Rensol Console buckets (20 deg)
    2 panels (0.6 kWh) on the south-west-ish facing porch (26 deg)
    8 panels (2.4 kWh) on the south-west-ish facing main roof (35 deg)

    Just want it in now!
    • Martyn1981
    • By Martyn1981 4th Sep 18, 1:28 PM
    • 7,839 Posts
    • 12,466 Thanks
    Martyn1981
    Looks like a great price considering its Solaredge and 4 aspects.

    Will be fun looking at the different generation totals, but also the 'playback' feature showing actual gen (W's not Wh's) for each panel through the day.

    It does eventually get boring ..... apparently?
    Mart. Cardiff. 5.58 kWp PV systems (3.58 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
    • JKenH
    • By JKenH 4th Sep 18, 4:51 PM
    • 222 Posts
    • 943 Thanks
    JKenH
    That's interesting, I tried it and got a similar annual total to PVGIS (a bit less) but the monthly distribution was markedly different and more accurately reflected what I actually get.
    Originally posted by KevinG
    I put my system in and came up with a figure 7% less than PVGIS. I have always been interested to see how much I am losing out to a South facing system so ran the figures for my kwp and inclination but facing south and came up with a figure 15% less than when I did the same exercise on PVGIS. Over the year as a whole the PV Watts calculator gave me 85% of a south facing system compared to 77% with PVGIS. Given how much my system underperforms Merlin and Legoman (similar geographic area) in terms of Os, sadly, I think the PVGIS is closer to the mark.


    I also went through the hourly figures for my for set up and was surprised that the peak hourly readings were quite a bit less than what I have been seeing.
    Lincolnshire. 7.8 kWp system, (4.2 kw west facing panels , 3.6 kw east facing), Solis inverters, IBoost water heater.
    • Zarch
    • By Zarch 24th Sep 18, 8:03 PM
    • 154 Posts
    • 364 Thanks
    Zarch
    In other news..... the scaffolding has gone up today....
    • Zarch
    • By Zarch 28th Sep 18, 10:59 AM
    • 154 Posts
    • 364 Thanks
    Zarch
    I'm generating..... i'm generating!!

    17 x 300w panels installed and firing!

    Cannot recommend CTS Renewables enough. Top notch install, looks brill to my untrained eye, everything trunked away etc super neatly.

    Anyone who is in the Midlands/South Yorkshire area, give CTS a call if you're thinking about making the leap before the FIT disappears in March.

    Will post some pics once the scaffold comes down.

    Will also report back how that NE / SW split fairs through the day and how the 4 different aspects generate. The beauty of everything being SolarEdge.
    • JKenH
    • By JKenH 28th Sep 18, 1:08 PM
    • 222 Posts
    • 943 Thanks
    JKenH
    Happy days ��
    Lincolnshire. 7.8 kWp system, (4.2 kw west facing panels , 3.6 kw east facing), Solis inverters, IBoost water heater.
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