Discussion
Arnold Cunningham said:
Spent a lot of time on there. The only thing I can’t find on there is point in time KW, only average by month.
What's it suggest you'll generate in a year? I can tell you roughly what your peak generation could be.Also what direction are the two main sets of panels?
Edited by MaxFromage on Tuesday 13th September 22:23
dmsims said:
How do the outdoor batteries cope with cold ?
Easier just to look at a spec sheet. Some will have different charge/discharge rates. Some will include a battery heater which means you'll consume power just to keep the batteries running. But obviously helpful in a winter storm if you're operating in a power cut.MaxFromage said:
What's it suggest you'll generate in a year? I can tell you roughly what your peak generation could be.
Also what direction are the two main sets of panels?
South and East facing panels, but with bit more shading than is desirable going on from the gable end and a tree with a TPO on - hence there are a number of optimisers in the spec and I assume he's increased the % on the system loss diagram to counter that.Also what direction are the two main sets of panels?
If I plug the numbers in to https://re.jrc.ec.europa.eu/pvg_tools/en/ based on a 100% south or east panels I get slightly higher numbers at the top end, but that doesn't factor in the shading I think.
Edited by Arnold Cunningham on Wednesday 14th September 08:26
Edited by Arnold Cunningham on Wednesday 14th September 08:55
Seeking guidance. I got an indicative quote for solar in February. I didn’t proceed as I didn’t have the money at the time - the outlay was ~£12k. I’ve just got them to actually inspect the roof and give my a more precise estimate.
The number of panels is significantly lower than the original quote (8 vs 18) given the shape of the roof and the layout cannot be optimised like they thought (from the aerial photo.
The new quote has c.1.5k of additional stuff (bigger battery and optimisers for shading) but the actual quote is near identical!
Have the cost of panels gone up that much in 6 months?! Or is it just that they can charge such a premium as they are getting so many enquiries?
Payback time has gone from 5 years to 10 years - and that is at a higher unit cost estimated.
I can’t get this to stack up, I don’t think
The number of panels is significantly lower than the original quote (8 vs 18) given the shape of the roof and the layout cannot be optimised like they thought (from the aerial photo.
The new quote has c.1.5k of additional stuff (bigger battery and optimisers for shading) but the actual quote is near identical!
Have the cost of panels gone up that much in 6 months?! Or is it just that they can charge such a premium as they are getting so many enquiries?
Payback time has gone from 5 years to 10 years - and that is at a higher unit cost estimated.
I can’t get this to stack up, I don’t think
sammyb349 said:
Seeking guidance. I got an indicative quote for solar in February. I didn’t proceed as I didn’t have the money at the time - the outlay was ~£12k. I’ve just got them to actually inspect the roof and give my a more precise estimate.
The number of panels is significantly lower than the original quote (8 vs 18) given the shape of the roof and the layout cannot be optimised like they thought (from the aerial photo.
The new quote has c.1.5k of additional stuff (bigger battery and optimisers for shading) but the actual quote is near identical!
Have the cost of panels gone up that much in 6 months?! Or is it just that they can charge such a premium as they are getting so many enquiries?
Payback time has gone from 5 years to 10 years - and that is at a higher unit cost estimated.
I can’t get this to stack up, I don’t think
For comparative purposes, you can look all the main components up for pricing - albeit you're most likely looking at retail prices.The number of panels is significantly lower than the original quote (8 vs 18) given the shape of the roof and the layout cannot be optimised like they thought (from the aerial photo.
The new quote has c.1.5k of additional stuff (bigger battery and optimisers for shading) but the actual quote is near identical!
Have the cost of panels gone up that much in 6 months?! Or is it just that they can charge such a premium as they are getting so many enquiries?
Payback time has gone from 5 years to 10 years - and that is at a higher unit cost estimated.
I can’t get this to stack up, I don’t think
For example, the battery I'm being quoted for is this one : https://batteryfactory.co.uk/collections/lithium-b...
And the inverter is this one : https://batteryfactory.co.uk/collections/inverters...
And Panels, you'd have to hunt around a bit to match the spec. but you could start here : https://batteryfactory.co.uk/collections/solar-pan...
But you can see the difference between a 5.2 and 9.5kwh battery is broadly £1,200.
https://batteryfactory.co.uk/collections/lithium-b...
https://batteryfactory.co.uk/collections/lithium-b...
And IIRC optimisers are about £50 each - in our design, he's quoted for 8.
So you can see where the money has gone, at least.
Hi all
I'm being tasked with looking at potentially fitting solar panels to a block of flats that we own 1 of 16 of. Aside from the complications of how we actually fairly distribute what's generated (13 are holiday homes, only 3 are full time residents so use a lot more power than the rest - thoughts welcome on how to overcome that one!) it's the actual fixing that I'd love your input on.
We're about to have a new 800sqm flat roof installed, the block faces south with no obstacles until you hit France so seems ideal for solar. I had expected as part of the new roof to fit a series of upright 'stubs' that we could then in the future essentially scaffold off for the solar, however the roofing contractors are all telling me that the usual way to do solar on a flat roof like this is with ballast.
Is that correct? It feels slightly unnerving as it's bang on the south coast so gets some pretty serious weather at times!
I'm being tasked with looking at potentially fitting solar panels to a block of flats that we own 1 of 16 of. Aside from the complications of how we actually fairly distribute what's generated (13 are holiday homes, only 3 are full time residents so use a lot more power than the rest - thoughts welcome on how to overcome that one!) it's the actual fixing that I'd love your input on.
We're about to have a new 800sqm flat roof installed, the block faces south with no obstacles until you hit France so seems ideal for solar. I had expected as part of the new roof to fit a series of upright 'stubs' that we could then in the future essentially scaffold off for the solar, however the roofing contractors are all telling me that the usual way to do solar on a flat roof like this is with ballast.
Is that correct? It feels slightly unnerving as it's bang on the south coast so gets some pretty serious weather at times!
My install goes in early Jan. 15 panels and a 10Kw battery. One thing I'm curious about is running the house of solar in the event of a power cut. The battery and inverter is Solar Edge and I stumbled across this: https://www.solaredge.com/uk/products/battery-stor...
My installer told me that they aren't ratified for use in the UK yet. Is there any alternative to island the house?
My installer told me that they aren't ratified for use in the UK yet. Is there any alternative to island the house?
Well no doubt they won't want to risk a breach of the roof and therefore cause a warranty issue but it would have to be all signed off and designed as part of the manufacturer's spec anyway so if it were to happen it would be covered.
Their provision is for additional 'loose laid' felt laid upside down (presumably for grip) to protect the new roof and then the ballast / array goes on top of that. All the contractors have said similar but I guess I'd just like to know that it is indeed standard or whether they're taking the easy option!
Their provision is for additional 'loose laid' felt laid upside down (presumably for grip) to protect the new roof and then the ballast / array goes on top of that. All the contractors have said similar but I guess I'd just like to know that it is indeed standard or whether they're taking the easy option!
sammyb349 said:
Seeking guidance. I got an indicative quote for solar in February. I didn’t proceed as I didn’t have the money at the time - the outlay was ~£12k. I’ve just got them to actually inspect the roof and give my a more precise estimate.
The number of panels is significantly lower than the original quote (8 vs 18) given the shape of the roof and the layout cannot be optimised like they thought (from the aerial photo.
The new quote has c.1.5k of additional stuff (bigger battery and optimisers for shading) but the actual quote is near identical!
Have the cost of panels gone up that much in 6 months?! Or is it just that they can charge such a premium as they are getting so many enquiries?
Payback time has gone from 5 years to 10 years - and that is at a higher unit cost estimated.
I can’t get this to stack up, I don’t think
Are they the same panels they've quoted for? You need to look at the capacity of the panels, not just the number.The number of panels is significantly lower than the original quote (8 vs 18) given the shape of the roof and the layout cannot be optimised like they thought (from the aerial photo.
The new quote has c.1.5k of additional stuff (bigger battery and optimisers for shading) but the actual quote is near identical!
Have the cost of panels gone up that much in 6 months?! Or is it just that they can charge such a premium as they are getting so many enquiries?
Payback time has gone from 5 years to 10 years - and that is at a higher unit cost estimated.
I can’t get this to stack up, I don’t think
Arnold Cunningham said:
South and East facing panels, but with bit more shading than is desirable going on from the gable end and a tree with a TPO on - hence there are a number of optimisers in the spec and I assume he's increased the % on the system loss diagram to counter that.
If I plug the numbers in to https://re.jrc.ec.europa.eu/pvg_tools/en/ based on a 100% south or east panels I get slightly higher numbers at the top end, but that doesn't factor in the shading I think.
Ok. I'm not a specialist/installer, but I am an accountant and can work numbers. In May/June/July/August around the few hours of clear blue sky, midday sun, you will be generating 6-7kwh. For the sake of a few hundred quid, I would be upgrading to an 8kw inverter.If I plug the numbers in to https://re.jrc.ec.europa.eu/pvg_tools/en/ based on a 100% south or east panels I get slightly higher numbers at the top end, but that doesn't factor in the shading I think.
Edited by Arnold Cunningham on Wednesday 14th September 08:26
Edited by Arnold Cunningham on Wednesday 14th September 08:55
The issue with that is that it'd either move us off the GivEnergy platform, or staying on their platform and running a pair of seperate inverters, chargers & batteries. So I totally hear you, but the incremental cost to do that was quite high go up to hardware that, as a next step up, still only supports 6kw (ie 2x 3kw).
I can see some bigger domestic inverters around, but to that was a different platform entirely. For the sake of potentially losing a few kwh here and there it seemed like quite a lot of extra cost when "on average" the system is producing under that, the "cost/benefit" needle seemed to be hard to justify. And bigger single units than that seemed like it was heading towards 3 phase platforms.
So it seemed that overalll, more panels to create the highest average power output we can, but acknowledging that during very high peak times there will be some "clipping" was the compromise unless we went with a different architecture. At least, that was the chaps guidance. Nevertheless a this is a good discussion and I acknowledge your point and this is all a great learning exercise. I know I'm doing it a bit "in public" on this thread - but I hope might be useful for others to learn from my experience, including any mistakes I'll inevitably make on the way.
For learning purposes, would you mind explaining the maths you did there?
Am also pleased to report they've confirmed the order.
I've also started trying to switch my octopus energy account to their "go" tariff without owning an EV yet so will report back how that goes.
(There is part of me that's also wondered about buying a field on the isle of wight and filling it full of panels)
I can see some bigger domestic inverters around, but to that was a different platform entirely. For the sake of potentially losing a few kwh here and there it seemed like quite a lot of extra cost when "on average" the system is producing under that, the "cost/benefit" needle seemed to be hard to justify. And bigger single units than that seemed like it was heading towards 3 phase platforms.
So it seemed that overalll, more panels to create the highest average power output we can, but acknowledging that during very high peak times there will be some "clipping" was the compromise unless we went with a different architecture. At least, that was the chaps guidance. Nevertheless a this is a good discussion and I acknowledge your point and this is all a great learning exercise. I know I'm doing it a bit "in public" on this thread - but I hope might be useful for others to learn from my experience, including any mistakes I'll inevitably make on the way.
For learning purposes, would you mind explaining the maths you did there?
Am also pleased to report they've confirmed the order.
I've also started trying to switch my octopus energy account to their "go" tariff without owning an EV yet so will report back how that goes.
(There is part of me that's also wondered about buying a field on the isle of wight and filling it full of panels)
Edited by Arnold Cunningham on Wednesday 14th September 12:10
I've just spoken to my buddy with a 4KW array. He's going to double check exactly tonight, but he's convinced on his setup, east facing, clear view of the sky, that he's never seen more than 2.5KW of peak power. Applying that factor (0.625) to my design (I will have some south facing panels, but I also have obstructions & shadows) comes in at 5.25 peak power. So based on that calc, I'd be binning 250W for a couple of hours a day during the absolute height of summer. The rest of the year, I'll be well under.
It'll be interesting to see the numbers that come out once it's installed, sadly it'll be another 11 months or so before we can validate. Wonder what page no. this thread will be on to by then.
It'll be interesting to see the numbers that come out once it's installed, sadly it'll be another 11 months or so before we can validate. Wonder what page no. this thread will be on to by then.
Fair enough, I can see the issue there. I think the losses will be significant, but it would be a number of years until you paid for the upgrade given the circumstances. Especially as you probably will be generating significant excess in those conditions so will only be losing out at (crappy) export rates. As an example today, our install is 16.3kw directly East/West, split 50/50. No shading. Right now it's generating just over 10kwh with the sun partly shaded.
In terms of the calculations I did, it's more knowing what my system is doing and comparing my PVGIS model with what your model suggests. From that I just compared generation by month and scaled back the peaks I've seen in our system. It's hard to see how much shading you have, but those south facing panels look good, along with the early sun on the east panels. It'll be the afternoon/evenings when you lose out on generation, so the battery will help there.
In terms of the calculations I did, it's more knowing what my system is doing and comparing my PVGIS model with what your model suggests. From that I just compared generation by month and scaled back the peaks I've seen in our system. It's hard to see how much shading you have, but those south facing panels look good, along with the early sun on the east panels. It'll be the afternoon/evenings when you lose out on generation, so the battery will help there.
Arnold Cunningham said:
I've just spoken to my buddy with a 4KW array. He's going to double check exactly tonight, but he's convinced on his setup, east facing, clear view of the sky, that he's never seen more than 2.5KW of peak power. Applying that factor (0.625) to my design (I will have some south facing panels, but I also have obstructions & shadows) comes in at 5.25 peak power. So based on that calc, I'd be binning 250W for a couple of hours a day during the absolute height of summer. The rest of the year, I'll be well under.
It'll be interesting to see the numbers that come out once it's installed, sadly it'll be another 11 months or so before we can validate. Wonder what page no. this thread will be on to by then.
You have a good chunk facing south as you say, that makes a huge difference. I can believe his figures, but I'd add 20%+ onto yours even if there is some shading. You then get to my calcs. The range isn't just height of summer though- it's May to August really if you look at your model.It'll be interesting to see the numbers that come out once it's installed, sadly it'll be another 11 months or so before we can validate. Wonder what page no. this thread will be on to by then.
Either way, given your circumstances, it's the way to go.
Certainly, if we were in a different league of power generation, I would scale up the inverter a lot. My brief to the guy was to be pragmatic about cost/benefit.
He did offer a pair of inverters that would have up to handled 10KW and been able to charge a pair of 9.5KW batteries to full capacity in a 4 hour "cheap" power period - but it was a big step up price wise for not so much benefit.
Nearly 20KW is good going though!
We can't have west side of the garage (shaded by the house) or west side gable end (shaded by the chimney and not much space). I did ask about more panels on the conservatory roof, but he felt a bit to low and therefore shaded. We also considered west side of the gable, but that became hard to integrate for not much benefit - basicallly the south panels will be on one string/circuit and the east panels on the other with individual optimisers to deal with shading.
To add west in he felt it'd want a different circuit really, and for just 2 panels it was hard to justify.
So the only answer is to buy a bigger house - but I'm too old to want to take on another chunk of mortgage and not clever enough to do it without.
He did offer a pair of inverters that would have up to handled 10KW and been able to charge a pair of 9.5KW batteries to full capacity in a 4 hour "cheap" power period - but it was a big step up price wise for not so much benefit.
Nearly 20KW is good going though!
We can't have west side of the garage (shaded by the house) or west side gable end (shaded by the chimney and not much space). I did ask about more panels on the conservatory roof, but he felt a bit to low and therefore shaded. We also considered west side of the gable, but that became hard to integrate for not much benefit - basicallly the south panels will be on one string/circuit and the east panels on the other with individual optimisers to deal with shading.
To add west in he felt it'd want a different circuit really, and for just 2 panels it was hard to justify.
So the only answer is to buy a bigger house - but I'm too old to want to take on another chunk of mortgage and not clever enough to do it without.
Edited by Arnold Cunningham on Wednesday 14th September 13:37
MaxFromage said:
As an example today, our install is 16.3kw directly East/West, split 50/50. No shading. Right now it's generating just over 10kwh with the sun partly shaded.
This is a great fact. If our setup were producing 5KW right now, I'd be happy as larry. Would I be even happier if it was producing 5.15 though? 
Edited by Arnold Cunningham on Wednesday 14th September 18:31
Arnold Cunningham said:
In the last decade of doing work on our house (we really should get a move on), the only time I've ever had anyone available "today" was the guy doing the leadwork on our roof. So in every other case, we have to be patient. I'm OK with that - I would prefer to be patient to get the right guys doing a nice job for a fair price (I did have one guy try to quote me 9K to do the leadwork and pointing in a couple of chimneys once - I assumed he didn't want the work).
So in this case, I kept badgering the original lot I was recommended. He's saying about 6 weeks lead time for a GivEnery setup which looks quite nice.
I wonder if they will line all the screwheads up vertically like the guy who rewired our house and a couple of years back. Almost seems a shame to have to modify his wiring - he takes a lot of pride in the job. I did check - he's not done the solar course yet so can't do the install.
Thanks, and good luck. Does he mean he can actually do the job in 6 weeks? Much quicker than I expected. What region (generally) is this?So in this case, I kept badgering the original lot I was recommended. He's saying about 6 weeks lead time for a GivEnery setup which looks quite nice.
I wonder if they will line all the screwheads up vertically like the guy who rewired our house and a couple of years back. Almost seems a shame to have to modify his wiring - he takes a lot of pride in the job. I did check - he's not done the solar course yet so can't do the install.
I have been wondering about the inverter size as per the other posts. I am tempted by the givenergy products too but will probably aim for a bigger inverter which might mean another supplier (estimate I can get 10Kw on roof, with possible growth to a bit more, all south facing).
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