Great summary, and thanks for sharing your journey. You may remember I also used Dorset Solar Solutions and have been blown away by the quality and service they offer, lovely couple too. For years we thought our SE roof was non optimal but 18 panels have outperformed the forecast in all months bar November (and probably December) thanks to persistent cloud. Interestingly my neighbour had a similar 12 panel array and slightly smaller inverter which performs better than mine on dull winter days. Keep up the great work!
Great to hear that you're also very pleased with the product and service offered by Dorset Solar Solutions! Do you think your neighbour has a lower start up voltage perhaps?
Which option to go with really depends on your own roof setup i.e. area, orientation, pitch and obstructions. In my instance, I opted for option A. In light of your evidence, if my budget was higher, I would definitely go with both A & B. Credit to you for taking a big risk with the NW panels against all the advice, it has paid off for you nicely. A 5 year 8 month pay back is a fantastic ROI.
Definitely. I hope if nothing else, this video will help people to do the calculations, the modelling, the projections, rather than just relying on rules of thumb. In the past this has resulted in many people, including our neighbours, friends and family all thinking they can't have solar on their roofs. Massive credit to Martin from Dorset Solar Solutions. Most others were so insistent that the NW roof was a waste of time. Martin took the time to do the modelling in opensolar and realised I might be onto something.
Thanks for this series of videos, UDF. North-facing panels for the win! 😃 I'm going to spend some time working out how the scaffolding industry works, but for me, that's the next barrier to people getting solar installations (a) in the first place, and (b) on additional roof facets - I just cannot see why it is so expensive, given it's a basic service with heavily-commoditised equipment.
Thanks for your support Gary 👍 Scaffolding is also a mystery to me. Had a couple of chats with solar installers who are very frustrated at having to work with scaffolders who are expensive and sometimes unreliable. With my cavalier attitude to health and safety I'd be up a DIY scaffold tower 😁
I maintain the trucks for three local scaffold firms, there can be a lot of expense there, buying the trucks and running them. One customer recently updated their fleet, but still have a lot of expense due to modern emissions problems and the shear cost of parts. I've no idea what scaffolders get paid, but it's a skilled and dangerous trade so I expect wages are high. What amazes me is the distance some of them travel for jobs, there are loads of scaffolding firms everywhere, but one of ours based near Dover regularly goes to Hastings and London, you'd think a local firm would cheaper.
Maybe room for a solar panel focused scaffolding company to be created. I've got a good relationship with scaffolding company so I get good pricing and no pressure to remove it with those absurd weekly charges, but that is me and the nice guys I've found. I think someone could easily make a market out of just focusing on serving renewables consumer base with a less predatory practice and still make a good margin.
@@alex75hgft I don't think that will work, why only focus on a fraction of the potential market. I've never known anyone be charged a weekly amount for scaffolding, it's usually a struggle to get it down.
You're both bang on it. Scaffolding really mucks about with the sums. I'm considering north only install to avoid additional Scaffolding on a multi pitch south roof. Option B!
This summer i was in my garden looking up my almost exactly N facing roof and the sun was shining full on the roof (no panels though) so i can see exactly where you're coming from. As you said seems this years weather has helped, the more diffuse the light eg cloudy then the direction is less relevant and Oct-Dec has been miserable weather wise.. I did , in effect what you did re your N vs S, to explain, I have a S facing garage roof which isn't worth installing by itself due to shading during mornings and afternoon, however the incremental cost when i3w as getting the house roof done made it a no brainer, as i effectively just paid for the panels.
8:30 A or B ? I'd go for option B. Fit as many panels as you can. I live in the lucky country. 30 panels 13.2kw with a 10kw inverter. In six months it has just produced 9MWh😯 (only just - I'm really pleased). Almost exported twice as much as we've used. The drawback is our feed in tariff is 8 cents kwh. Compared to our peak rate of 55c per kWh (feed in 7kwh to get 1 kwh at night - no net metering here). My cost of production is 0.6cents per kwh for 9 years. I expect the system to last longer that thou. I intend to get a battery next year which will increase my production costs but my energy resilience will get me close to independence. My next water bill will be more than my power. All the best for your journey.
It’s interesting that your generation exceeded expectations even when it was generally considered a bad solar year. A good year would absolutely smash it! 🎉 Great summary as always. 👍
My roof is E/W facing with about 4kW of panels on each face and three verticle panels on my south facing wall , I produced 6,500kWh solar in the last year. My two powerwalls charged with 4300kWh and supplied 3600kWh. All solar is exported in the summer. This year I have imported 9400kWh at 7p and exported 6000kWh at 15p so well happy with that over £200 surplus, giving us "free" heating and motoring! Simply not possible without batteries.
Extremely valuable data, thanks for breaking this all down! I am definitely going to throw a few panels onto the north side of my garage roof and test it out. I probably won't do as well given that my garage is almost directly north-south at roughly 15 degrees, so the low angle of the sun more or less means that the north side does not get much direct sun in the winter at all. But then again, the south side of my garage roof gets quite a bit of shade from nearby trees in the winter too. I think I can get fairly good augmentation of my current generation even with the north orientation and angle. I think I am going to run a test. Since we are in winter right now. I can stick one residential (bifacial, half-cut... a modern panel) up there just connected up to a power station or something like that and see what the panel is actually able to produce. I'll bet it actually does fairly well, particularly in cloudy weather, verses the south side. -Matt
Like you I went with Option B. Size over orientation. I maxed out the WSW facing roof with 12 panels and the ENE roof with 7 panels due to gable issues. 5Mwh for the year, very happy with that. Payback is looking at year 7. Interested to know how you calculate your cost benefit, there are so many ways I have seen of doing it, i'm just plain confused !Gave up in the end and just used Gary Waites spreadsheet from his channel.
It is interesting, back in 2018 I had to search quite a bit to get an installer who would put panels on an east west roof as they stated the payback would not be good. 6 years on and the 10 east and 10 west panels yield about 10% more than our 16 south panels. The useful aspect of the east west array is the seasonal yield which follows the seasons. Payback wise, I believe we are now evens after 6 years, but it depends on how you calculate things and the variable nature of electricity prices. Really my conclusion is with the way panels have advanced, if a location has a good surface area (aka startup voltage) then put panels on !
Yes, very useful watching this year and I am now seriously considering adding to my South facing Panels on the North aspect. Truly eye opening to a noob like me and extremely useful. So glad you ignored the naysayers.
Thanks for the post. Just shows panels should be fitted to every roof space. I also have a small North west roof, looks like I will be installing another 5 panels but don’t tell the wife 😆
Your videos are incredibly useful. I have a NE roof (+ large SW area). From your data the NE seems very useful on high generation months for maximising production. How is it in lower generation months - how much does it help when there is little generated on the SE?
I have a long bungalow where the length is faing east/west. I'm looking at 18 panels split over the east /west roof with only 3 facing south :( Octopus seem to think that it will be a good ROI so let's see...
Put 6 NW and 6SE 360w SolarEdge panels (with built in optimisers) in nearly 3 years ago. No regrets, get about 3MW out and NW are 50%+ of SE. Did this on detached garage rather than main house roof, all installed in 1 day!
Having my East and West roof covered in January, with an 11KWH battery. Really looking forward to doing my little bit to help the planet, never have a power cut and saving more than the £200 per year that the money is earning in interest in the bank❤❤.
Here's an interesting question for you. If your house was 180 degrees the other way round, would you have fitted the six panels on what would then have been the northwest side? Personally I tend towards filling the roof with solar. It's hard to get a great return on investment that is tax free and reduces your bills such that you don't need as much money to live on and can either consider working less, or having more money from working the same amount. And it's green. I should have thought of it when I had mine done!
I don't think I have seen you split out how the NW panels are performing against PVGIS at the given orientation and slope (aside from suggesting it is 'better')?
This is really is really interesting. We have 8 SE panels currently but was thinking about adding 8 to NW roof to the spare string. Especially with the price of panels now!
I have done so and 8 NW 430Wp panels add about 2100 kWh to my home, despite shade from a dormer (fixed this with Enphase micro inverters on a separate circuit). Both roofs do not peak at the same time, so unless the inverter is already clipping the solar production, it should be a great addition.
@@neutron6220 Yes! Although i'm not sure about those biracial panels you mention! Auto-correct never gets in the way of political correctness it seems!
I should be doing something similar soon, and i had similar feedback from installers saying it is going to be a waste of time. This makes me comfortable with my decision. The only difference will be some 20 or 30kwh of batteries on top as the price seems to be fairly good.
Will you be posting the results for the whole month of December when they come in which I'd like to compare with mine? I had my installation - East/West - just a week ago and so far the results have been dismal (about 0.26 KWHr per Kwp per day).
Depends on the setup and panels. we have 10 east and 20 west (5.9kwp) and for the last 30 days we yielded, 37kwh compared to our 16 panel south array (4.9kwp) yielding 35kwh. Over the year 4.7mwh for the east west array and 3.8mwh for the south array. The install has been installed since 2018 and the totals are 32.8mwh for east west and 28.6mwh for south. An east west setup does work well.
Hi there I'm thinking of getting panels (just got a heat pump) but afraid that any changes in the export prices in the UK will decimate the payback period. In fact, all online calculators quote 2/3 of the ROI as coming from the export rather than domestic use. This is calculated on the 15p/kWh by Octopus. Any thoughts of this? How likely is the UK to eventually fall into the same export price trap as California?
Yes, I think we'll get there eventually but I don't think it will be in the next few years. Before we get to net metering (or worse), we will see the gradual decline of export rates over several years most likely. I'm making hay whilst the sun shines.
@@UpsideDownFork probably not, you are right, but probably yes within the 7-8 year return period... In your experience on reading up on the topic, how easy is it to retrofit a battery if one wasn't installed together with the panels? This could be a good way to combat the eventual slump in export price. On the other hand, the UK definitely isn't California in weather terms...
@antanasmelinis6769 if you have a hybrid inverter fitted by a qualified electrician then adding a battery can be DIY for many reasonably competent home owners.
@@antanasmelinis6769I imagine if someone has an old inverter and wants to add a battery they could buy a battery with built in inverter like powerwall 3
Enjoyed your presentation and was surprised the total cost was as low as it was. My only caveat is the way you allocated costs tonthe NW section adding £1k from the SE which was fine for your circumstance given the 2 phases of installation, however if you were to install panels on as a single installation how might your experiment have looked as thats my most likely route? As conventional wisdom only states S facing panels give the optimum return but hardly anyone has a house with the ideal orientation.
Option C, do as many roofs as possible, ideally all at the same time. I will be interested to see your choice of battery, and size. I've swapped to Go, first day my electric costs including SC was 2p, I expect the second day will be similar, that was yesterday. That's extremely low for December. I've been on Flux since April 2023, last year and this year my total cost for gas and electric has been negative, I've calculated that running the entire year on Go I'll be a further £300 negative.
You mention start up is better for the NW panels. Could you explain that some more, like how much earlier do the NW panels start up? This might be worth making a separate video about. If I understand it correctly, you have 16 panels on one string (facing NW) and 6 panels on the other string (facing SE). I am not sure I understand why the start-up voltage would matter so much. The way I understand it, the voltage produced by the panels depends on how much current you draw from them and the temperature of the panels. If your panels get hot, the voltage drops and you want to have a string size that does not get below the start up voltage. E.g. if your Voc is 28 V, and the operating range is 65-450 V, start-up voltage 120 V, 6 panels will start up at 168 V and 16 panels at 448 V. The voltage will get lower at high temperatures and when the panels produce power, the MPPT will draw current and find a lower voltage point where it can get the most power out of the panels. Note that I think this also means that the NW facing panels might not be able to operate in very low temperatures as the Voc would be more than 28 V and so the string voltage would be above 450 V. To avoid such problems you might consider making two strings of 11 panels, since you have optimizers which can compensate for the difference in orientation. If there really is so much difference in start-up time for the different strings, I would love to see some examples. You should have the data for that.
@@UpsideDownFork Thank you. I watched the video. It mostly confirms my thoughts above. But it doesn't address why the NW facing panels start up earlier than the SE facing panels. In the example you give, I can't see much difference. I get the impression that it is more about watts/amps than about volts. The more Wp you connect to an inverter, the sooner it will produce enough amps at the string voltage, to make the inverter start working. That means that it might still be a good idea to connect two strings of 11 panels, instead of 1 string of 6 and two strings of 8.
@@GerbenWulff Yes, for me it's that 16 panels can generate more than 6 panels can in low and diffused light conditions. The start-up voltage and current requirement of the MPPT are satisfied earlier with the parallel-series configuration of my NW roof. It's not specific to the orientation, but just the sheer surface area and resulting output.
@@UpsideDownFork Since those 16 panels are all connected to a single MPPT, did you ever get their output clipped? You have 6,720 Wp on what I think is a 5.2 kW MPPT.
Looking at your system may have been better to only have the north and spent the money from not doing the south panels and bought a battery, better control and quicker payback hindsight is a wonderful thing.
NW not N - makes a difference. You put the panels on NW because that's what you had available. I have SW roof and that gives 6000kWh/y. Also depends on technology. Maybe new stuff better. Mine is 8 years old. On a sunny day in autumn the generation can drop from 5kW to 1kW as soon as the shadow from next door's roof touches the bottom of the strings in the afternoon. The other side of roof NE only gets a small amount or direct sun around mid June when the sun is low in the sky early and late in the day and when you don't need it. I guess SEG has changed this financial calculation as well. I was on deemed export via the original FIT for most of the time as I had no smart meter.
Shouldn't this video be done in January on the anniversary of your install? Okay, I know you're not going to get much generation between 17th Dec and 27th Jan but thats 41 days of actual precious data missing! 👮♂ and it could highlight your need for a bigger battery 🙃🍴
Thanks for all your work to share this very enlightening data
You're welcome 🤗
Great summary, and thanks for sharing your journey. You may remember I also used Dorset Solar Solutions and have been blown away by the quality and service they offer, lovely couple too.
For years we thought our SE roof was non optimal but 18 panels have outperformed the forecast in all months bar November (and probably December) thanks to persistent cloud.
Interestingly my neighbour had a similar 12 panel array and slightly smaller inverter which performs better than mine on dull winter days.
Keep up the great work!
Great to hear that you're also very pleased with the product and service offered by Dorset Solar Solutions!
Do you think your neighbour has a lower start up voltage perhaps?
@ Probably, plus my larger inverter consumes more power. On sunny days my system way outperforms his, but on days like today he always wins.
@@WessexWeather ah yes. Got it 👍
Which option to go with really depends on your own roof setup i.e. area, orientation, pitch and obstructions. In my instance, I opted for option A. In light of your evidence, if my budget was higher, I would definitely go with both A & B.
Credit to you for taking a big risk with the NW panels against all the advice, it has paid off for you nicely. A 5 year 8 month pay back is a fantastic ROI.
Definitely. I hope if nothing else, this video will help people to do the calculations, the modelling, the projections, rather than just relying on rules of thumb.
In the past this has resulted in many people, including our neighbours, friends and family all thinking they can't have solar on their roofs.
Massive credit to Martin from Dorset Solar Solutions. Most others were so insistent that the NW roof was a waste of time. Martin took the time to do the modelling in opensolar and realised I might be onto something.
Thanks for your efforts this year, happy holidays to you and your family
Thank you.
Same to you!
Thanks for this series of videos, UDF. North-facing panels for the win! 😃 I'm going to spend some time working out how the scaffolding industry works, but for me, that's the next barrier to people getting solar installations (a) in the first place, and (b) on additional roof facets - I just cannot see why it is so expensive, given it's a basic service with heavily-commoditised equipment.
Thanks for your support Gary 👍
Scaffolding is also a mystery to me. Had a couple of chats with solar installers who are very frustrated at having to work with scaffolders who are expensive and sometimes unreliable.
With my cavalier attitude to health and safety I'd be up a DIY scaffold tower 😁
I maintain the trucks for three local scaffold firms, there can be a lot of expense there, buying the trucks and running them. One customer recently updated their fleet, but still have a lot of expense due to modern emissions problems and the shear cost of parts. I've no idea what scaffolders get paid, but it's a skilled and dangerous trade so I expect wages are high. What amazes me is the distance some of them travel for jobs, there are loads of scaffolding firms everywhere, but one of ours based near Dover regularly goes to Hastings and London, you'd think a local firm would cheaper.
Maybe room for a solar panel focused scaffolding company to be created. I've got a good relationship with scaffolding company so I get good pricing and no pressure to remove it with those absurd weekly charges, but that is me and the nice guys I've found. I think someone could easily make a market out of just focusing on serving renewables consumer base with a less predatory practice and still make a good margin.
@@alex75hgft I don't think that will work, why only focus on a fraction of the potential market. I've never known anyone be charged a weekly amount for scaffolding, it's usually a struggle to get it down.
You're both bang on it. Scaffolding really mucks about with the sums. I'm considering north only install to avoid additional Scaffolding on a multi pitch south roof. Option B!
This summer i was in my garden looking up my almost exactly N facing roof and the sun was shining full on the roof (no panels though) so i can see exactly where you're coming from.
As you said seems this years weather has helped, the more diffuse the light eg cloudy then the direction is less relevant and Oct-Dec has been miserable weather wise..
I did , in effect what you did re your N vs S, to explain, I have a S facing garage roof which isn't worth installing by itself due to shading during mornings and afternoon, however the incremental cost when i3w as getting the house roof done made it a no brainer, as i effectively just paid for the panels.
Thanks for commenting!
8:30 A or B ?
I'd go for option B. Fit as many panels as you can.
I live in the lucky country.
30 panels 13.2kw with a 10kw inverter.
In six months it has just produced 9MWh😯 (only just - I'm really pleased). Almost exported twice as much as we've used. The drawback is our feed in tariff is 8 cents kwh. Compared to our peak rate of 55c per kWh (feed in 7kwh to get 1 kwh at night - no net metering here).
My cost of production is 0.6cents per kwh for 9 years. I expect the system to last longer that thou.
I intend to get a battery next year which will increase my production costs but my energy resilience will get me close to independence.
My next water bill will be more than my power.
All the best for your journey.
Nice!!
You are creating very helpful videos
Glad you think so!
It’s interesting that your generation exceeded expectations even when it was generally considered a bad solar year. A good year would absolutely smash it! 🎉 Great summary as always. 👍
I hope so! Looking forward to a better 2025🤞
My roof is E/W facing with about 4kW of panels on each face and three verticle panels on my south facing wall , I produced 6,500kWh solar in the last year. My two powerwalls charged with 4300kWh and supplied 3600kWh. All solar is exported in the summer. This year I have imported 9400kWh at 7p and exported 6000kWh at 15p so well happy with that over £200 surplus, giving us "free" heating and motoring! Simply not possible without batteries.
Excellent work!
Thanks for the very good info as always
You're welcome!
Extremely valuable data, thanks for breaking this all down! I am definitely going to throw a few panels onto the north side of my garage roof and test it out. I probably won't do as well given that my garage is almost directly north-south at roughly 15 degrees, so the low angle of the sun more or less means that the north side does not get much direct sun in the winter at all.
But then again, the south side of my garage roof gets quite a bit of shade from nearby trees in the winter too. I think I can get fairly good augmentation of my current generation even with the north orientation and angle.
I think I am going to run a test. Since we are in winter right now. I can stick one residential (bifacial, half-cut... a modern panel) up there just connected up to a power station or something like that and see what the panel is actually able to produce. I'll bet it actually does fairly well, particularly in cloudy weather, verses the south side.
-Matt
Nice. You can't beat a real world test!
Like you I went with Option B. Size over orientation. I maxed out the WSW facing roof with 12 panels and the ENE roof with 7 panels due to gable issues. 5Mwh for the year, very happy with that. Payback is looking at year 7. Interested to know how you calculate your cost benefit, there are so many ways I have seen of doing it, i'm just plain confused !Gave up in the end and just used Gary Waites spreadsheet from his channel.
Sounds great!
Payback video is on the way.
I'll be showing a couple of ways to calculate it as some people are optimistic and some pessimistic!
Many thanks 👍
It is interesting, back in 2018 I had to search quite a bit to get an installer who would put panels on an east west roof as they stated the payback would not be good. 6 years on and the 10 east and 10 west panels yield about 10% more than our 16 south panels. The useful aspect of the east west array is the seasonal yield which follows the seasons. Payback wise, I believe we are now evens after 6 years, but it depends on how you calculate things and the variable nature of electricity prices. Really my conclusion is with the way panels have advanced, if a location has a good surface area (aka startup voltage) then put panels on !
Yes, agreed!
Yes, very useful watching this year and I am now seriously considering adding to my South facing Panels on the North aspect. Truly eye opening to a noob like me and extremely useful. So glad you ignored the naysayers.
Glad it was helpful!
@@UpsideDownFork the entire year has been helpful. Thank you very much for taking the time
Have you estimated your north facing generation using PVGIS or a solar company site?
Thanks for the post. Just shows panels should be fitted to every roof space. I also have a small North west roof, looks like I will be installing another 5 panels but don’t tell the wife 😆
Yes!
Your videos are incredibly useful. I have a NE roof (+ large SW area). From your data the NE seems very useful on high generation months for maximising production. How is it in lower generation months - how much does it help when there is little generated on the SE?
Rewind to the section where I show the monthly balance of generation NW vs SE 👍
Just before watching the video, I noticed some discolouration on some of your modules. Are you worried at all about that? Back to viewing now 🙏
Nope. That was at time of installation. The discolouration disappeared after the first rain 👍
I have a long bungalow where the length is faing east/west. I'm looking at 18 panels split over the east /west roof with only 3 facing south :(
Octopus seem to think that it will be a good ROI so let's see...
East / west is a great roof to have! You will get generation when you need it most in the morning and evenings.
Put 6 NW and 6SE 360w SolarEdge panels (with built in optimisers) in nearly 3 years ago. No regrets, get about 3MW out and NW are 50%+ of SE. Did this on detached garage rather than main house roof, all installed in 1 day!
1 day installation, nice 👍
Having my East and West roof covered in January, with an 11KWH battery. Really looking forward to doing my little bit to help the planet, never have a power cut and saving more than the £200 per year that the money is earning in interest in the bank❤❤.
Great stuff! 😎
Maybe the sum is max number of panels with min amount spent on scaffolding?
Yes! That's it.
Panels on all roofs facing all directions here in Dorset please 🎉 thanks for sharing.
Yes sir!
Here's an interesting question for you. If your house was 180 degrees the other way round, would you have fitted the six panels on what would then have been the northwest side?
Personally I tend towards filling the roof with solar. It's hard to get a great return on investment that is tax free and reduces your bills such that you don't need as much money to live on and can either consider working less, or having more money from working the same amount. And it's green. I should have thought of it when I had mine done!
Easy answer.
No chance I'd put 6 panels on the NW if I could get 16 on the SE!
I don't think I have seen you split out how the NW panels are performing against PVGIS at the given orientation and slope (aside from suggesting it is 'better')?
This is really is really interesting. We have 8 SE panels currently but was thinking about adding 8 to NW roof to the spare string. Especially with the price of panels now!
Yep, I agree.
It may not have been economically viable just a few years ago to fit on suboptimal roofs but these days it seems like a no brainer.
If you have to upgrade the inverter, maybe not economically viable?
I have done so and 8 NW 430Wp panels add about 2100 kWh to my home, despite shade from a dormer (fixed this with Enphase micro inverters on a separate circuit).
Both roofs do not peak at the same time, so unless the inverter is already clipping the solar production, it should be a great addition.
@@UpsideDownFork can get 445w trina biracial panels for £47 each. Crazy how much the panels have come down in price
@@neutron6220 Yes!
Although i'm not sure about those biracial panels you mention!
Auto-correct never gets in the way of political correctness it seems!
is the 16 panel array wired as two 8 panel arrays ? into one MPPT via two string inputs ? or as one big 16 panel series array ?
8 in series and then those 2 in parallel into one MPPT.
I should be doing something similar soon, and i had similar feedback from installers saying it is going to be a waste of time. This makes me comfortable with my decision. The only difference will be some 20 or 30kwh of batteries on top as the price seems to be fairly good.
Great stuff!
Give us the exact orientation. Or are they exactly NW?
I guess a big difference between NNW & WNW
@@markthomasson5077 yes, exactly NW. 👍
Will you be posting the results for the whole month of December when they come in which I'd like to compare with mine? I had my installation - East/West - just a week ago and so far the results have been dismal (about 0.26 KWHr per Kwp per day).
Sure.
I'm currently getting 2-6kWh per day.
Full monthly amounts will come 👍
Depends on the setup and panels. we have 10 east and 20 west (5.9kwp) and for the last 30 days we yielded, 37kwh compared to our 16 panel south array (4.9kwp) yielding 35kwh. Over the year 4.7mwh for the east west array and 3.8mwh for the south array. The install has been installed since 2018 and the totals are 32.8mwh for east west and 28.6mwh for south. An east west setup does work well.
Hi there
I'm thinking of getting panels (just got a heat pump) but afraid that any changes in the export prices in the UK will decimate the payback period. In fact, all online calculators quote 2/3 of the ROI as coming from the export rather than domestic use. This is calculated on the 15p/kWh by Octopus. Any thoughts of this? How likely is the UK to eventually fall into the same export price trap as California?
Yes, I think we'll get there eventually but I don't think it will be in the next few years.
Before we get to net metering (or worse), we will see the gradual decline of export rates over several years most likely.
I'm making hay whilst the sun shines.
@@UpsideDownFork probably not, you are right, but probably yes within the 7-8 year return period... In your experience on reading up on the topic, how easy is it to retrofit a battery if one wasn't installed together with the panels? This could be a good way to combat the eventual slump in export price.
On the other hand, the UK definitely isn't California in weather terms...
@antanasmelinis6769 if you have a hybrid inverter fitted by a qualified electrician then adding a battery can be DIY for many reasonably competent home owners.
@@antanasmelinis6769I imagine if someone has an old inverter and wants to add a battery they could buy a battery with built in inverter like powerwall 3
Enjoyed your presentation and was surprised the total cost was as low as it was.
My only caveat is the way you allocated costs tonthe NW section adding £1k from the SE which was fine for your circumstance given the 2 phases of installation, however if you were to install panels on as a single installation how might your experiment have looked as thats my most likely route? As conventional wisdom only states S facing panels give the optimum return but hardly anyone has a house with the ideal orientation.
Great point!
Agreed, I would have allocated 6/22 of the cost to SE panels for obvious reasons.@@UpsideDownFork
I have 2 identical arrays either side of garage roof, same panels. Ratio ESE array 56%, WNW array 44%. North Cheshire
Nice, thanks for sharing!
Option C, do as many roofs as possible, ideally all at the same time. I will be interested to see your choice of battery, and size. I've swapped to Go, first day my electric costs including SC was 2p, I expect the second day will be similar, that was yesterday. That's extremely low for December. I've been on Flux since April 2023, last year and this year my total cost for gas and electric has been negative, I've calculated that running the entire year on Go I'll be a further £300 negative.
Option C it is!
So is that about 7 years pay back at about the price cap?
You cover at the end. Oops.
Eager beaver! Coming to the channel soon!
You mention start up is better for the NW panels. Could you explain that some more, like how much earlier do the NW panels start up? This might be worth making a separate video about. If I understand it correctly, you have 16 panels on one string (facing NW) and 6 panels on the other string (facing SE).
I am not sure I understand why the start-up voltage would matter so much. The way I understand it, the voltage produced by the panels depends on how much current you draw from them and the temperature of the panels. If your panels get hot, the voltage drops and you want to have a string size that does not get below the start up voltage.
E.g. if your Voc is 28 V, and the operating range is 65-450 V, start-up voltage 120 V, 6 panels will start up at 168 V and 16 panels at 448 V. The voltage will get lower at high temperatures and when the panels produce power, the MPPT will draw current and find a lower voltage point where it can get the most power out of the panels.
Note that I think this also means that the NW facing panels might not be able to operate in very low temperatures as the Voc would be more than 28 V and so the string voltage would be above 450 V.
To avoid such problems you might consider making two strings of 11 panels, since you have optimizers which can compensate for the difference in orientation.
If there really is so much difference in start-up time for the different strings, I would love to see some examples. You should have the data for that.
You can see more about my strings and their start-up voltage (and current) here: th-cam.com/video/Qfi5dZPN91k/w-d-xo.html
@@UpsideDownFork Thank you. I watched the video.
It mostly confirms my thoughts above. But it doesn't address why the NW facing panels start up earlier than the SE facing panels. In the example you give, I can't see much difference. I get the impression that it is more about watts/amps than about volts. The more Wp you connect to an inverter, the sooner it will produce enough amps at the string voltage, to make the inverter start working.
That means that it might still be a good idea to connect two strings of 11 panels, instead of 1 string of 6 and two strings of 8.
@@GerbenWulff Yes, for me it's that 16 panels can generate more than 6 panels can in low and diffused light conditions. The start-up voltage and current requirement of the MPPT are satisfied earlier with the parallel-series configuration of my NW roof.
It's not specific to the orientation, but just the sheer surface area and resulting output.
@@UpsideDownFork Since those 16 panels are all connected to a single MPPT, did you ever get their output clipped? You have 6,720 Wp on what I think is a 5.2 kW MPPT.
My NW panels have generated 61% compared to the SE facing panels, slightly worse than your 76% results ☹️
I wonder why that is? Roof angle? String size? Shading?
Looking at your system may have been better to only have the north and spent the money from not doing the south panels and bought a battery, better control and quicker payback hindsight is a wonderful thing.
@@4yourgarden yes. If I had to do it again, that's what I would do 👍
@@UpsideDownFork spoilers?...
NW not N - makes a difference. You put the panels on NW because that's what you had available. I have SW roof and that gives 6000kWh/y. Also depends on technology. Maybe new stuff better. Mine is 8 years old. On a sunny day in autumn the generation can drop from 5kW to 1kW as soon as the shadow from next door's roof touches the bottom of the strings in the afternoon. The other side of roof NE only gets a small amount or direct sun around mid June when the sun is low in the sky early and late in the day and when you don't need it. I guess SEG has changed this financial calculation as well. I was on deemed export via the original FIT for most of the time as I had no smart meter.
That's it. We all have to work with what we have 👍
Shouldn't this video be done in January on the anniversary of your install?
Okay, I know you're not going to get much generation between 17th Dec and 27th Jan but thats 41 days of actual precious data missing! 👮♂ and it could highlight your need for a bigger battery 🙃🍴
True. More coming. Just trying to break it down so I don't need up with one 30 minute long video at the end of the year!
@@UpsideDownFork
Forgot to mention ... Option B, fill every bit of a roof
DeScript is what you need to not have to worry about changing your words on the video not syncing with your lips. Failing that 11 labs.
Thanks. It was a very poor joke on my behalf. The video was from the beginning of the year. The voice over from last week!