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@daffy, I'm assuming your baseline is actual data from a year back? (rather than an unreasonable expectation of what you'd generate?)
At the other end of the scale: 12 old panels in a valley (so partially shaded) and East:West (so presumably not as good as 12 all south facing).
Yesterday: 8kw generated!
I think it's the heat holding them back rather than any kind of problem but what's people's view? - get someone out to service/assess they're all working fine? Get up there and clean them?
My challenge is I don't have much in the way of reporting from 12yrs back to say that the generation would have been any different back then
My array wasn’t activated until late November last year, but was installed in September, so no data to directly compare to. What I’m comparing to is generation in March and May.
in March we were getting sustained peaks of 5.3kW, in May, it was sustained at 5.2kW, the rare days in August when it was sunny for longer periods were 4.6kW, now we’re down to 4-4.2kW. It could be simply what happens in September with the sun at a less than optimal angle, it could be dirt, temperature or something else or even a combination, but I think cleaning has to be the first step.
Our generation of the last 4-5days has been around 30kWh a day.
Ah, got you. I'd be surprised 9 months later if you're experiencing degradation as a result of dirty panels but it's a nice easy action to take
It could be simply what happens in September with the sun at a less than optimal angle, it could be dirt, temperature or something else or even a combination, but I think cleaning has to be the first step.
Mine are the same. I doubt it’s dirt - we’re just a long way past the solar irradiance peak of mid June and you should expect similar generation capabilities to early April. Couple this with hot panels and the output looks about right.
FWIW I have a 12 panel east/west split and generated 14 kWh yesterday. That would have been 30 kWh in June. Not helped at this time of year by tall trees to the west of the house.
August figures for us:
Production - 957
Import - 275
Export - 705
Net profit from Octopus for period 20July to 20 August was £91
Octopus give the breakdown of which rates we export at on flux.
We sold: 545 kWh @ 19.3p and 155 @31.4p
Had a quick look at production peaks vs temperature. Comparing two very sunny days. 8th June, whole day average temperature was 14.9, peak output was 5.86kw. This Monday, average temp was 20.9 and peak was 5.01. Panels are 2 years old and never been cleaned (its on the list!)
but what size is the array?
should we be putting together a spreadsheet on this?
From memory @lodger ‘s array is one of the largest in this thread - 10kWp split E/W, is that right?
Yes- well remembered.
10kwp
1/3 East, 2/3 West
10kw battery
6kw max inverter capacity
.
managed to get my export sorted out and onto octopus flux
3.9kw south southeast 30 odd degree roof , 10.4 kwh battery
tiny bit of charge off peak to 30% every morning, usually 1-2kwh at most, and discharging down to 65% on peak has been bringing in £5-7 a day now that the lad is at school and there's no one home. quite interested to see what octopus actually work out on their statement
They’re quite dirty up close - apologies for my drone skills…
from a distance they seem fine.
Our upstairs back rooms (south facing) get very warm at times like now. Expect increased insulation in loft would help to limit solar gain from roof through to upstairs room ceilings, but wondering how much of an effect having solar panels on the roof would make?
Found the following comment online:
For the benefit of the panel life and output, we space the panels 100mm (6″) off the roof surface. This creates a perfect forced cooling area as heated air below the panels rises and flows upward as hot air does, and drags in much cooler more dense air. as heat rises, it remains close to the backs of the panels and hardly ever reaches the actual roof surface at high temperatures. The roof tiles are merely warm to the touch, not almost unpleasant to the touch like exposed to sun tiles are.
Is there an optimum install for this kind of issue?
In my experience. Very very minimal difference to internal temperatures
I've a story and a half and we sleep in the roof space. When it's sunny it's hot.
I did however insulate the eaves last winter with super foil and glass wool. And it's not been so wild this year.
Great thinking to use the drone, I'd not have thought the camera could pick up such good detail.
I'm tempted to get up on my roof and clean my panels now - move over Rod Hull!
this popped up on my insta feed yesterday
https://sunology.eu/en-gb/products/sunology-play-kit-solaire?
Now, I'm not really thinking of getting anything like this, but it made me wonder if, and how it works?
I assume it's solar to inverter, then they say, just plug it into a 13 amp socket and you have power 'feeding in'. If it does indeed feed in, I'm assuming it'll only be for the power ring it's plugged into, and will suppliment the demand on that ring, and of course, only in the daytime.
is it really that simple? I didn't think that you could just plug in say, a generator, into your 13A socket to power the ring up?
I've little idea about house electrics, but as it popped up on insta, it may well be BS.
It's not
It is in Germany and France though
Well, the panels are now clean(er) and there seemed to be a period after cleaning where the power generation stayed stable rather than it’s usual past the high point decline, but this could’ve just been sun intensity change at the time.
if it was as seemed, the change would be around 8-10%. They were surprisingly filthy.
I’ll keep an eye on it and report back.
Are there any tools/mega spreadsheets for calculating ROI on panels/batteries? Our new extension has room for a 3kw array, and we are home 5 days out of 7, using power. I imagine that with a touch of optimisation (schedule washing machine and hot water tank for the days we're out etc), that a no battery option would export a small enough amount of power to make the economics of a battery not worth it (I'd probably want a 200% ROI over 15 years to be worth the faff),
General rule of thumb is annual generation is = kWp of the array, so 3kWp =3000kWh/y assuming unshaded, southish facing and above 30deg.
Without a battery, I’d say you’d be lucky to use 2/3 of that even with someone at home most of the time as, outside of summer, you don’t get smooth, regular power generation.
A small battery is probably worth having, especially given the recent drop in prices as it will allow you to make use of a lot more of what you generate.
@5lab. I'm in a similar position (panels but not a massive amount spare). Added to that I can't get paid (again) for the export as I'm on FIT. What it means is I need to "harvest" every kw as I get paid for it regardless.
I couldn't make the numbers on a battery to work so went with a solar diverter into the hot water tank. Not particularly amazing returns to date but hopefully ballpark returns that you'd hoped for - the key being a much maller initial outlay.
Not sure if that helps but thought I'd say where my head went
I’m thinking about switching to octopus agile over flux.
Is there an easy way to automate usage with WiFi plugs or will it take over my life?
Can I automate the input of the inverter interface too so it charges batteries at the optimum time? ( interface is just input boxes for charge start and stop so it won’t do it by itself)
I'm still on flx, still a better deal for me right now
rnning home assistant with givetcp to control my givenergy inverter and predbat to calcualte best charge and discharge times, also works on agile i believe
-We're still on flux, but're charging in the mornings at 50amps to get upto 8-9kWh into the packs during the cheaper periods. If we then export during the day, it's cost neurtal ish and keeps us off mains power until the next morning.
We're spending around £2.50 a day (inc standing charge) but have also exported around 60kWh, so still close to cost neutral. This is just in the last week and was triggered by several really dull days where we only accumulated 8kWh over 3 days! This meant we were drawing power at expensive rates rather than using the battery smartly.
Sticking with Flux here. Charging each night at the cheap rate, sending any modest surplus to grid each 4-7pm slot. Its a simple to understand tariff so I like it.
Mid Sept -march I just charge at night. If I generate anything meaningful I'm happy to export it.
Not set up any peak export from my batteries
Looking for a little bit of advice if I may..
I’m lucky enough to have had my panels installed back in 2011 when the good feed in tariffs were around. I’m looking to add some battery storage to my system but wondered if it affects my generation payment ? I’m currently earning around £2300 a year in generation so don’t want to lose that.
I’ve recently added an iboost to my system so for 8 months of the year the solar panels heat my water tank so has made a nice reduction to my gas usage.
Next stage is obviously batteries to reduce my electricity bills further.
What should I be looking to pay for say a 9.5kw battery system ? Seems a bit of a minefield out there at the moment. E-on for example are quoting £9000. Assuming this is the higher end of the scale being a big business and offering incentives such as 0% finance bumping up the price ?
Also do we think there will be any schemes such as the ev tariffs for over night charging coming for people with solars and batteries? It’s very unlikely there will be an ev in my household at least in the next 5 years but would be nice to do some cheap over night charging when the solars haven’t filled up the batteries
I’m looking to get something setup for Easter time next year so time to start getting the wheels rolling
Thanks all!!
I don’t think it will affect your FIT as you’re not changing the generation capability of the system, are you? No new panels?
The cost of the battery install will depend on if a new inverter is required. Even so, £9k seems quite high to me. A new inverter is £1500 and a 10kWh battery would be ~£5k and the install should be both easy and fairly cheap. I’d say £7500 Inc VAT for battery, inverter and install would be my ballpark.
They’re quite dirty up close – apologies for my drone skills…
Is your local window cleaner on the ball and up to date? 😀
https://window-cleaning-drones.com/#content-1
Thanks for the reply. I’m assuming I’ll need a new inverter. I suppose the display will still record what has been generated and I’ll add it to the closing figure of the old unit when it gets removed.
Winrya, I'm in a similar position to yourself. I couldn't caculate a reasonable payback on the battery but did look at my FiT administrators T&Cs and see a clause saying that I must notify [i.e. the key being not "ask"] them if I add a battery. Your call if you do, as I'm sure plenty apply the logic of let sleeping dogs lie but my view is that they have no right to say no and I wouldn't want to get kicked off FiT on a technicality.
Are you sure you have enough excess to warrant both the solar divertor and a battery? - sorry to ask as I appreciate everyone's situation is different but I haven't
£9,000 seems a lot considering that the only work required is to replace the inverter and connect up the batteries, as you've already got a grid and solar connection in place. The only issue I can foresee is if the inverter is in the loft, as you won't necessarily want 9 kWh of battery over your head.
I'd be tempted to find a local installer. To be honest I'm a bit surprised that the Government is prepared to slash green subsidies but is keeping the FIT payment scheme going, but I suppose many of their cronies invested early on in the bigger schemes.
I’m looking to add some battery storage to my system but wondered if it affects my generation payment
I may be wrong but I'm pretty sure it will affect your FIT payment.
Under the terms of the agreement you are not allowed to make any changes to your system - so you can't just change the inverter,
my view is that they have no right to say no and I wouldn’t want to get kicked off FiT on a technicality.
I'd say it's not a technicality at all, surely adding batteries is not allowed as that would consume power that you would have exported (and you are being paid on an assumed 50% export of total generation).
Happy to be proven wrong but it's a pretty big risk that I'm happy for you to take - I'm keeping my system as it was installed but may add another separate one as that would be fine.
winrya - We were in a similar situation, and added battery storage on the 'house side' of all the feed in gubbins so didn't make any changes to the solar system for the purpose of the FIT. - Its a bit less efficient that charging directly from the solar inverter, but we didn't want to risk losing the FIT. - Clearly you have to check your own Ts & Cs.
@Flaperon. The FiT scheme is now closed to new applications. Existing FiT schemes have a contract to be paid for 25 years so the government have no say over the matter.
@sharkbait. It's a fair point, I couldn't get payback to work on either a battery or a new array so no risk here.
so the government have no say over the matter.
Just change the law and be done with it? FIT is basically a spectacular bung to the richest in society.
Has Intelligent Octopus with Solar and Storage been done yet.
Import rate is 7.5p
Export rate can move from SEG 4.1p to 15p on this tariff.
Depending on EV mileage and efficiency a net zero bill for home and ev is possible
I even discharge any remaining stationary into the grid before the cheap period.
Happy days!
Just change the law and be done with it?
OK.
Has Intelligent Octopus with Solar and Storage been done yet.
Import rate is 7.5p
Export rate can move from SEG 4.1p to 15p on this tariff.
Depending on EV mileage and efficiency a net zero bill for home and ev is possible
I even discharge any remaining stationary into the grid before the cheap period.
Happy days!
With announcements such as Octopus launching thier own heat pumps as well, is the next step a really tightly integrated and smart home energy management system which 'talks' to all the energy production, storage and use devices in the home?
https://www.independent.co.uk/tech/solar-panel-price-fossil-fuels-energy-b2418124.html/blockquote >
I really dislike these assessments. Whilst the panel price has dropped and the cell price has dropped. The cost of labour has gone up and this is by far the biggest largest cost of installing the array. Materials for my array were £3k, but the installed price for the array was close to £11k (In roof so £2k more). Battery costs for solar haven't really dropped. You're still generally looking at £0.5k per kWh of storage. Labour on a big array might be cheaper, but for houses.It's now looking like a 10y breakeven point.
<p style="text-align: left;">Just climbed up for a closer look and the panels are pretty grubby. Looking online for telescopic poles etc. Was going to get a water-fed one that can also dispense soap, but could be a lot cheaper just to get a squeegie on a pole and only do it in heavy rain? Anyone have a recommendation? 
</p>
Thanks for the replies guys. Looks like I best dig out my t&c’s. I don’t want to break the contract as the generation payment will be worth a lot over the next 13 years. I’d be happy to lose my export money as they only pay me 4.82p per kw currently (for an estimated 50% of my generation) but my generation earns 69p per kw and rises to £1.22 per kw by the end of the term.
I’ll also checkout some reviews of local companies and get some prices and go from there. It should be an easy install everything is inside the garage with plenty of room for a couple of batteries
I bought this from Amazon [url] https://www.amazon.co.uk/dp/B0BL7DV5RW?ref=ppx_yo2ov_dt_b_product_details&th=1 [/url] Which I connected to my pressure washer and foam dispenser...it worked okay from the ladder, but was bloody heavy and unwieldy and not particularly good from that position. In the end I went up to the ridge with the thing and worked from the top down. That worked much better and I actually felt safer.
FWIW - I'm definitely getting more power after cleaning them. Even at this time of year, we're now regularly cracking 5kWp whereas before it was stopping at 4-4.2kWp even in periods of intense sun. .