Weird. Lets me send a single line of text. But not the text I want to send
Following my off the cuff thought of degradation on 7 y.o. system, prompted me to look back at the data...
Year Mains Solar iBoost
2018 2211 3586 1518
2019 2972 3786 2245
2020 3010 3690 2199
2021 2721 3635 2093
2022 2199 3764 2291 (to 9 Dec)
So actually, I can stop being paranoid about panel degradation!
On the iBoost, we only moved in to the house full time September 2018, the 14 months prior to that the place was being ripped apart having total refurb. Also looks like we'll end the year on ~2400kWh for mains leccy, like everyone else we made an effort to reduce usage this year. (Edit : Excel cut'n'paste formating still poor)
3.6kwP 260 degrees orientation 6. something Kwh today. Lovely sunny day but very cold which is beneficial for generation. System is 12 years old so not too bad really.
managed 10 Kwh today from mine. 4.8 KwP on due south facing 40 degree roof. In a narrow valley so sunrise over the hill is currently 10.30 with sunset around 3.30
Full moon and clear skies yesterday evening and I found myself strangely delighted to see my system was generating 1W, yes, that right, 1 whole watt of clean green electricity, at midnight...
🙂
We made 1today and 12 for the month to date. It's been grim and at best grey.
We made just 54kwh in Dec last year but ramped up quickly in January to 140 and 270 in Feb then ran at 500ave through to October.
im averaging 1.2kw a day huddersfield.
The last 2 days have been bright and ive seen the output just to 800w instantaneous where as its usually 200w. this makes me think the low sun is basically meaning there in shade all the time.
going to keep an eye on it.
We made 1today
What kinda magic system do you have......only got 0.5 today.
7.18kWh today in Derbyshire. 3.85kWp system facing SSE at about 40 degrees. Almost cloudless day but the low angle means one of my panels is in partial shade all day.
Full moon and clear skies yesterday evening and I found myself strangely delighted to see my system was generating 1W, yes, that right, 1 whole watt of clean green electricity, at midnight…
Can you still claim the FIT payments if you're moonlighting?
Has anyone got either a Solax or a Givergy battery? Any good?
We've got a givenergy system; I've been very impressed. The web app or phone app is good, with real time updates if you're home or five minute updates if you're not, power and energy graphs over different time periods, and a load of options to allow you to tune when and how the battery is charged and discharged.
It all works over their cloud system but apparently the inverters talk modbus and people have got raspberry pis and things talking to them.
It's very dependent on angle and orientation at this time of year. Our 9 east-facing panels generated almost nothing today because the sun never got warm enough to burn through the frost on the panels. The west facing ones did better, and by 2pm we had bursts of 3kw, but only managed a total of 6.3.
Our neighbours over the road have 20 ESE facing panels and they only got about 2kwh for the day.
I, personally, have expended hundreds of Kwh of mental energy that would have been better spent just working and not fussing about optimising a few pence worth of electricity!
I, personally, have expended hundreds of Kwh of mental energy that would have been better spent just working and not fussing about optimising a few pence worth of electricity!
But where's the fun in that 🙂
Our solar installation progresses.
Roof now has 18 panels, 7.11kW iirc.
Shifted from on roof to inline setup when
1. Physical roof measurements meant a different panel distribution and number from original satellite guestimate
2. Roof needed redoing rather than repairing
3. Slate breakage was at 50% rather than an expected <20%
Roof work, aside from some pointing, finished yesterday. Looks neat.
Tesla Powerwall got mounted on the side of the house this morning.
Expecting work to resume in the new year.
I, personally, have expended hundreds of Kwh of mental energy that would have been better spent just working and not fussing about optimising a few pence worth of electricity!
Yes, I spent the first week just endlessly looking at the graphs and was considering adding optimisers, but they are out of stock right now. However, I've now lost interest and just let it do it's thing. Plus the scaffolding has come down, so now it's too late to change anything!
Slate breakage was at 50% rather than an expected <20%
I was surprised they broke - the installers turned up with loads spare and had to replace quite a few. Slate roof is only 25 ish years old as I had the whole thing redone shortly after moving in. When new, I remember running up and down the whole thing in trainers and nothing broke.
surprised they broke
our roofers were surprised at the breakage rate. The slates on one roof part they said were noticeably thinner and more fragile than on some other parts.
The roof was allegedly replaced within the last 50 years. 🤷🏻♂️ how many of the original Victorian slates were reused then. Victorian construction methods and materials are not always great 😑
10kW+ yesterday from my 5.6kW PV array. Today looks even better but unfortunately snow cover making them useless...
Quick Q @Surfer: Did you apply for and get permission for a 5.6Kw array or is the inverter limited to 4kW output?
(probably the latter but just curious)
My E/W array is shite in the winter.... just 3.6kWh yesterday 🙁
Definitely need to get a couple of south facing Kw in the paddock.
For the benefit of lambchop, I'm currently looking into a solar install (I live in South Devon). The best quote so far is a local installer, offering this for about £12k:
- 5.525kW solar array
- 13 Trina Vertex S 425W solar panels
- SolaX Triple 5.8kWh battery
- All the rest of the gubbins (inc scaffolding & install)
I have asked him to look at an option for optimisers too as our roof is a bit complicated and some panels may be shaded for some of the day. Of of the bigger firms was trying to sell a solaredge system, but googling them throws up lots of unhappy customers and they cost a good chunk more than other options.
Any opinions from the STW massive on this setup?
anyone got installer/supplier reccomendations in the south east? Brighton area specifically..
@sharkbait retrospective approval/informing for my array, yes 3.7kW inverter although it looks suspiciously like the 5kW model and I noticed I was using >4kW recently and was not drawing from the grid.... I need to double check the model number.
Being really lazy here... has anyone got a good Excel model for calculating benefits over time for a solar install?
@thinksta noticed yesterday loop have a solar benefit modeller. Think you need to link your smart meters so it's based on your usage.
Interesting - is Loop a kosher thing, or just a way to get and sell your data?
Home Assistant is your friend. I have it set up in Virtualbox at the moment on my mac using a Modbus connection. My setup is Foxess and their app doesnt show accurate PV, it adds the PV to your overnight charge. With HA you get an accurate figure. I just model that in a spreadsheet. I am sure I can output it from HA not worked it out yet.
This is yesterdays (I only set it up last week) and so far highest PV of 10.7kW.
It's a sunny day (albeit it was snowing when I rode to work this morning) - how's everyone doing?
This will be the first day since our array went live (November 21st) and the battery was installed (December 9th) that it looks like we'll get a full (12kWh) battery. It's only 12:30 and we're at 83% and charging at a rate of 3kw/h The array is currently generating about 3.3kW (or around 60% of capacity). I'm oddly excited - I don't think we've ever made it past 75%.
its not sunny here - but by the 10th jan id made more power than all of december .....
It was a sunny morning earlier, but it looks like the snow on our panels finally melted just in time for the sun to go in!
Tuesday (17th) was our best day recently by far, we did 16kwh instead of the usual 2-4 we've had for ages. I'm trying to persuade myself I can see the daily totals start to rise again as the days get longer...
only getting 1.4kw a day due to shading from my neighbor thats significantly worse than initially expected 🙁
the usual 2-4 we’ve had for ages.
Thats a hell of a range. I had just over 10 which was the highest so far but seldom dropped below about 5 on average. How big is your array?
The highest we've had since activation is 13kWh, but we've had a LOT of rain in January and so many of our days are 2-4kWh too. 5.4kW array - SSE facing. No shade after 10:30.
November 21st-30th was ~75kWh
December was 132kWh
January so far is 95kWh.
Truthfully, those are better than I expected.
Ours is 8kwp facing south east. We've had a lot of dreary days when it peaks at about 800w but the days are so short that it doesn't really do anything until 9:30 then it's gone again by 2:30. We've done 105kwh this month.
Worst day this winter was just before Christmas at 0.51kwh, can't do much with that!
My issue now is that having a non-grid-tied solar system, my batteries are full by midday and the solar just switches off as I have nowhere to export the excess solar. The other day I was getting 14 KW daily total and the batteries were still not quite topped up, now I am only gettting 8 KW a day, although the days are brighter, sunnier and longer. I have plans afoot to connect in my brothers house which will use a bit more and maybe then add immersions and do more cooking by electric.
My December total was 111 KWhs, January so far is already 93 (plus at least another 10 KWh from yesterday and today I was unable to use or store).
Those of you with solar batteries - what levels of discharge do you allow and at what rates?
Those of you with solar batteries – what levels of discharge do you allow and at what rates?
All controlled by the built in BMS (Battery Management System), which stops you knackering the cells (Huawei). Inverter can manage 3.8 KW IIRC.
ive got a pilontech 4.2kw. it will discharge at 3kw,
interestingly ive noticed that if i charge it to 100% from the mains then use it thoughout the day i find i use less energy overall ! still testing it for the next few days .
So our LG is a 13kWh battery with a usable capacity of 12kWh and will discharge at 5kW (or 7kw as a pulse load), but the inverter drops the rate of available discharge to 0.5kw below 25% and and 0.125kw below 20%. At 10% the inverter will force charge the battery to 20% from the grid.
What I'm interested in is if discharge protection should be % based or capacity based as the rates on the inverter are just defaults. 20% of my battery is almost 2.5kWh remaining whereas 20% of a 3 or 4kWh battery is 0.6>0.8kWh...see what I mean?
Can I zero it on the inverter as the battery has its own control system?
what levels of discharge do you allow and at what rates?
default was 20% and minimum is 10% so using the tried and tested logic I set it to 15%. My batteries are in the garage and I have had some unusual activity which I am assured is due to the cold but generally mine have behaved themselves.
I have a 5kW Inverter ( I think it should be 3.7....) so that is the charge and discharge limit.
see what I mean?
I assume your app allows you to change this? If so I am sure there is a point at which it will go no lower. Mine is 10%. This is an indication of what your manufacturer recommends and is controlled by the BMS. I found useful advice on a facebook page for owners of my model (Foxess) have a look if there is one for yours.
Just had a look at the BMS settings:
[url= https://live.staticflickr.com/65535/52638688280_a812b7f736_c.jp g" target="_blank">https://live.staticflickr.com/65535/52638688280_a812b7f736_c.jp g"/> [/img][/url][url= https://flic.kr/p/2ocv383 ]BMS Config[/url] by [url= https://www.flickr.com/photos/brf/ ]Ben Freeman[/url], on Flickr
Has anyone added additional battery capacity to their array after installation? Did you need to notify the DNO?
I've not done it...but why do you think you need to
Your changing capacity - not your ability to feed into the grid - that's controlled by your inverter.
When we were installing our array, SSEN wanted to know the type and size of the battery and the array being installed as they used sum total potential discharge (12.5kW) to determine the ability of the grid to handle the load. They didn’t accept the max limit on the inverter as an actual limit.
When we were installing our array, SSEN wanted to know the type and size of the battery and the array being installed as they used sum total potential discharge (12.5kW) to determine the ability of the grid to handle the load.
And yet they take the limit as gospel when you do a g98....... Even though you could stick nearly 8kw of panels on a 3.6kw inverter without exceeding string voltage.
They forced me into a G99 as the inverter was a physical 5kW unit with a software lock at 3.7kW. Delayed the whole thing for months. They also charged £700 to determine that “no modifications to the grid were required” to deal with their forced recognition of the 5kW limit and the 12.5kW potential discharge limit. PITA company to deal with.
My panels were installed in November 2022 but it wasn't until early this month that I got around to setting up Home assistant on my Raspberry Pi properly. I wont have a full month of numbers until the end of Feb as I missed the first 5 days of Jan but I am keen to estimate my payback period (£12k outlay)
Obviously many factors can change and the amount and way that we use electricity is key to these savings however what I am pleased about is how closely our monthly usage appears to align with the PVGIS Solar model. (PVGIS) which estimated around 160kW for January. If I take even a conservative average to compensate for the early days missed (they were shorter days) then I am slightly above this which is encouraging.
At this rate our payback will be 6.6 years which is impressive.
Surfer, how much effort was setting all of that up on Home Assistant? It’s loosely on my list of things to look at for keeping an eye on energy consumption.
Is it talking to a smart meter to monitor power in from the grid?
I know many of you are neck deep in the detail, but please can I go back to a basic 'what if?' question.
I have a SSW facing, low angle roof on two different storeys.
The higher roof gets sun most of the year, with a about a month where the shadow of the hill behind cuts across the roof mid-winter. The upper roof is only 6m wide and 3m deep.
The lower roof is shaded from sun for about 16 weeks of the year, due to the hillside. 10m wide and 2m deep.
This gives you an idea of the roofs and the slope we face. The back of the house is exactly SSW.
[url= https://live.staticflickr.com/2899/33244196413_7e7b5eeb3f_k.jp g" target="_blank">https://live.staticflickr.com/2899/33244196413_7e7b5eeb3f_k.jp g"/> [/img][/url][url= https://flic.kr/p/SDFcoe ]Garden[/url] by [url= https://www.flickr.com/photos/matt_outandabout/ ]Matt[/url], on Flickr
We are pricing up all sorts of renovation and improvement - we have no underfloor insulation, replace internal 'dot and dab' drafty plasterboard with proper plaster, remove and replace cavity wall insulation, re-plumb the heating system, new bathroom and kitchen. As part of this, solar seems another 'ought to do'.
I really don't want to spend huge sums and either not add enough value (and I know energy efficiency doesn't payback in the house selling market) or enough return on reduced bills.
Is the best thing to do to get a local company to do a survey and cost? I am planning same with our builder for other costs..
low hanging insulate first.
Sort the plumbing - Fit a tank not a combi.
solar later
Expensive / hard/ problematic insulating after
Anyway it seems that the suns back - our 4kw system is peaking over 3kw for prolonged periods for the first time this year. - its 11.30am and we have got 5kWh yield already - North east scotland
hasnt been past 1.5kw since about mid november - which isnt unusual.
remove and replace cavity wall insulation
How on earth do you do this without hacking lumps out of your walls? Is there some non-intrusive way of doing it?
Like trailrat says insulate first if practicable and fit a tank. Make sure heating pipework is at least 15mm so you have the option of fitting a heat pump later. In fact it might be worthwhile doing some homework on a heat pump anyway if you are replacing a boiler. Get a solar installer to do a survey. Wont cost you anything as they use Google Maps but make sure they know about and take into account your topography.
Anyway it seems that the suns back – our 4kw system is peaking over 3kw for prolonged periods for the first time this year. – its 11.30am and we have got 5kWh yield already – North east scotland
hasnt been past 1.5kw since about mid november – which isnt unusual.
only getting 500w on average bout 2kw a day
I'm just having my solar fitted today, not a pro by any stretch but have just been through the process for my situation.
A 6m x 3m roof is quite small compared to some of the systems discussed on here, i expect you'd get 5 or 6 panels on
top giving 2.7kwp, assuming 450w / panel. If motivated by financial savings the question will be how much of your generation you can get from your roof sizes given the shading issues. And whether its worth adding panels to the lower shaded pitches.
I'd first educate yourself a bit in the basics so you know what to ask for. I went in blind, was baffled, so spent some time researching. If you let suppliers dictate the solution you might just get what they want to sell. It's the easiest way so if you just want a quick look it might be fine for you - i was disappointed with the quality of the replies I got, they didnt tell me what i needed, so I think work it out for yourself first.
Find your average electricity consumption (average is around 10-12 kwh per day i think). See how much generation you could fit on your roof (start with 2.7kwh for just the top) and put that into an online tool like PVGIS. This will give you a figure for average generation you can expect for a given system size on your home (your azimuth and roof pitch). It doesn't estimate shading so you might have to add a fudge factor. When you factor in your electricity costs it'll quickly show you how much you might save on the bills. Then I'd start asking for quotes. Likely you'll want battery storage if your load patterns are average, probably quite small if you only put panels on the top roof, maybe 5-6kwh of storage. Too big and you might not charge it, unless you want to start charging during off peak rates (another kettle of fish).
How on earth do you do this without hacking lumps out of your walls? Is there some non-intrusive way of doing it?
Remove a few bricks from the bottom and the tops of the windows, place a length of flexible plastic/rubber into the end of a drill and slowly work the drill/plastic up from the bottom and down from the top. It'll mulch what's in there and allow it to be extracted at the bottom with a vacuum cleaner. The you block the lower holes and refill from the top ones with new stuff and block the holes.
It's time consuming compared to a first fill, but not overly difficult.
You’re in Wirral aren’t you?
I’m in Higher Bebington with a big South facing roof so your figures are pretty encouraging. I’m at home all day so could maximise usage.
It was pretty straightforward. Ethernet cable into the Inverter back to my home router then set up an Raspberry Pi that I already had. Hardest part was getting the cable through an outer wall (garage and house) and finding a USB keyboard.... After that it was straightforward and there are lots of Youtube videos outlining the steps and you can just download the HA image for your Pi. The inverter does all the clever stuff and you can then choose the entitie's that you want to monitor. It doesn't touch the smart meter but its easy to calculate the savings once you have accurate PV data.
@colp Yes, I would use the PVGIS site to calculate your estimated PV as I said I have found it accurate. Fortunate that we dont have any shading.
low hanging insulate first.
That's a given. The issue being, and why we've not done it so far, is that it is so intrusive and involves new kitchens etc
Cavity wall - part of the house is timber frame so can't be insulated. Part of the house is narrow cavity and cannot be insulated. The part that can be insulated has basically a few mm's of dusty, degraded foam. A quick hoover out from the bottom will be all it takes. But that means less than a third of the house can be cavity wall insulated.
Sort the plumbing – Fit a tank not a combi.
Sadly we've a 5 year old combi that I'm not replacing, but I will consider what we can do to make a tank easier when it does die.
It's a proper 'hard to treat' house insulation wise. It sits out of sun in the deep freeze for 12 weeks a year - meaning our winter heating is 30% more than friends with similar house in the sun.
I'm so tempted to sell and move...
Cheers, sadly I don’t have an inverter to plug it into as battery and solar is probably not on the list for this house. I was thinking about getting something set up so I’d had a bit of practice in monitoring useage when it did come to sizing a solar/battery system.
My figures are in for January (lets ignore tomorrow which is set to be a very sunny day and take it as given it will cover all my energy needs). Until this evening the panels have generated 191 KWh for the month (I fully expect another 12 KWh minimum tomorrow). In reality it has meant I have been completely disconnected from the grid for 20 days out of 30. Not bad for January. As production of solar ramps up we will be connecting in my brothers house next door to use the excess and if that doesn't use it all we will be fitting an immersion heater and turning off the oil-fired Rayburn that heats our hot water for a few months I hope.
I did some sums earlier today. I have used £116 worth of electric this month if I was buying it on my current contract. Because of the solar I will only have to pay £14.40
How many panels do you have strapped to the sheep though @welshfarmer? To give you that sort of production - 10kw?
lol. I have 12x400W panels on my house and 3 375W panels on the workshop. So just shy of 6KW total
I’m having 15 400w panels installed tomorrow. I hope to get as good production as you do! Probably not at optimally aligned as yours though. Only 5kw battery though so will need to try and use the power as generated.
Still haven’t worked out if the inverter they are fitting will enable an EPS or other form of grid disconnection.
188kWh for us with 94.5% self use. Not bad given that at this time of the year almost half our array is in shade until just before midday.
We still used almost another 300kWh from the grid, though I did try to charge the battery during the greenest periods.
The darkest 4 months of the year produce about 10% of my annual output, so it's not a killer if they are shaded. You might consider micro-inverters, ie, each panel has a separate inverter so that it can be optimised individually when part of the array is shaded. If you have string inverters (ie, serving a string of panels) and one panel is even partly shaded, the inverter has to reduce the output from all of them.
That’s not entirely true with modern panels. Most modern panels have multiple diodes that allow partial suspension of a panel with affecting the whole string.
On ours in the early morning 2/3rds of 6 of the 7 panels that make up the lower string are in shade from the neighbouring roof. That string produces less power, but not nothing. It’ll be something like 1500W for the unshaded string and maybe 450-500W for the string with one clear panel and 6 panels which’re 2/3 shaded.
@muddyjames so long as your panels are orientated roughly south-SW at around 35-40 degree pitch you should be able to outdo me as we are in a fairly narrow valley between 2000 foot hills. In Dec-Jan the direct sunlight doesn't hit the panels until 10 am and then is gone again by 4 pm. In fact there were 2 days during the snow when the panels shut down due to the batteries being full and we had no other way to use the energy. Based on the previous sunnny days we missed out on another 10 KWh of solar there. However, I think we have been lucky this year with it being a particularly bright January. In comparison, during December we only produced 111 KW in total, though I didn't fit the 3 extra panels until the middle of the month.
Hang on. I seem to recall I know who Muddyjames is so you know exactly where I live and what the topography is like! 😉
I didn’t realise that shading isn’t such a problem for modern panels sounds like I have wasted some money on the optimisers.
I don’t know about wasted. In theory the optimisers should be more efficient at load balancing than the diodes as the diodes have a discrete capability where the optimisers are continuous, so you should still get more. It’s just less of a clear case than when panels were without or with only a single diode.
If you have string inverters (ie, serving a string of panels) and one panel is even partly shaded, the inverter has to reduce the output from all of them
Not exactly true. We have a dual MPPT inverter with an input of each of our E/W strings - this way the east facing string does not pull down the generation when the sun is in the west.
I didn’t realise that shading isn’t such a problem for modern panels sounds like I have wasted some money on the optimisers.
I don't think you have. The issue I have with micro-inverters/optimisers is that if one fails you need to get back on the roof (so scaffolding cost), find out which one has failed and replace it. Or just leave the panel dead.
I don't know how reliable they are but you've certainly got many (?) more points of failure compared to a single inverter that is easily accessed!
My roof is split about 50/50 sw/se so semi optimal.
Myeddi - diverter of choice? Easy diy install?
@matt_outandabout I have a solar calculator I built for my project you can have, it's an excel spreadsheet that just needs angles for the panels inputting, you can then overlay the top of the hill (pretty sure I built that in) and see what kind of operating envelope you have. If trail rat's figures are anything to go by it's accurate enough.
That might be worth a look at - can you PM me?
Myeddi – diverter of choice? Easy diy install?
Cant comment on the Myeddi but I have an iBoost which was fitted as part of my overall install and I would have done it myself in a few minutes.
Does anyone have a recommendation for tidying up the wires of an external pair of batteries, connectors, coupler, inverter?
I was thinking of galvanised conduit, but the cables are pretty thick 20mm and I'm not sure they're go round corners very easily and even when they do, they'll terminate near the various boxes and just sort of pop out near them.
Any suggestions? At the moment it's only 3 cables from the battery to the inverter, but it'll soon be 9 cables in a mix of black red and orange.
Wouldnt it be easier to just trim and crimp them to the right and matching length and colour and leave them exposed. I hate untidy cables (I worked in IT infrastructure for years) but sometimes if the colours are coded correctly, straight and parallel lengths and neatly installed they can look better than some conduit or containment. If they are not pristine then you could look at something like this, flexible conduit from the top of the stack of batteries then a wide conduit on the wall with the same conduit breaking out.
Does gas & electric kwh produce the same amount of heat for water, trying to work out if it's worth switching off the iboost?
Just using round figures, if you can sell excess electricity for 15p per kwh and only pay 10p per kwh for gas, surely you're better off switching off the iboost and taking the 5p difference ... unless for some reason a kwh of gas isn't as efficient at heating water?
Also any idea how many kwh it takes to make a difference to hot water, we have a 300 L tank with 2 x 3 kwh immersions of which one is wired via the iboost, 0.83 kwh went to heating hot water yesterday (after fully charging batteries) which I'm guessing would have diddly squat impact on a tank that size?
Electric water heating is close to 100% efficient, gas boilers around 94% + losses from pipes between the boiler and the tank. I think gas heating the tank should come out ahead if the pipe run is well enough insulated. On top of that, add in the pump at 1 kW electric...
"Just using round figures, if you can sell excess electricity for 15p per kwh and only pay 10p per kwh for gas, surely you’re better off switching off the iboost and taking the 5p difference"
Your assuming that they use the same amount of kW for each to deliver the same amount of hot water. My boiler is ancient so efficiency is not great but I suspect all boilers use comparably more gas per hot water heated.
I only use my iBoost for free solar not as our main way of heating water. We use gas heating at the moment and hot water is a by product.
Edit: what has happened to the quote feature...
Your assuming that they use the same amount of kW for each to deliver the same amount of hot water.
I wasn't assuming at all it's the whole reason I posted it as a question and the post starts off .... "Does gas & electric kwh produce the same amount of heat for water"
As Murray says, electricity is more efficient however it is also more expensive.
