Solar / Battery Storage considerations

He had three daughters and two sons. Lots of them now. The Crawfords now have his farm.

Phil

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What’s the Uncles family name?

Perhaps @Richard.Dane will pass you my email address. Thanks Richard

It’s a small place - he married a neighbour’s daughter (a Walker) - other descendants still live there.

Phil

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We finally had a sunny winters day yesterday. We generated about 26 kWh, covering all our daylight use (including a spa :sunglasses:) with about 11 kWh exported that we then bought back at a higher rate when it was dark. Pretty good for mid winter.

The solar app gives up this data (but is less accurate than the incoming meter):

Our power companies app shows how that breaks down into power charges:

Today was cloudy and we generated about 11 kWh. I found the solar radiation records for the airport next to where we live. Basically, we are at the lowest monthly average for the year, and it will double by the equinox and quadruple for summer, so let’s to look forward to over the year.

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That is a good question, it does seem to depend where you live and your climate … but if you live in arable rural location you can expect after 5 to 7 years a film of algae on your roof (and walls) certainly in the climate of East Anglia … and any tile or panel cells.
There are treatments, but in my experience they are useless after 5 years or so, and you will need to clean.

I do detest panels on pitched roofs… but looking at option of new high efficiency panels on some of my flat roofs… which probably offer the most consistent locations at my property. I understand one should slightly pitch the panels to optimise solar reception (but not too much such that requires planning permission) and help mitigate water ingress and ice damage. Also the flat roofs are easier to maintain the panels (clean etc)
Anyone done this?

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My summer project is to chop the wood for the winter. I bought a Fiskar log splitting axe a few weeks ago and have been chopping lately. I probably have 2-3 years of wood stacked neatly. It is yew and fir cut about 5-6 years ago from an aunt’s property where we tried getting planning permission for a new house at the bottom of a large garden. The trees grew into the highway a bit. The logs from the bottom are at least 600mm but cut thinner. Yew is very sappy but the seasoning seems to have left dry wood. It should burn well. This is nature’s energy storage.

The sledge hammer is to deal with logs that the axe doesn’t chop through. The axe is about 2.5kg with a carbon fibre handle. The handle is a little shorter than I like so the logs are placed on a chopping block so there is something to stop the axe. I’m trying to avoid my legs doing that job!

Phil

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I really messed up my shoulder one log season from the constant jarring which needed a few visits to the chiropractor at some cost. I then bought an electric log splitter for future seasons.

My axe is quite light and the handle seems to cushion the impact. If I hold the handle tight while using the sledge hammer their is intense vibration- obviously I don’t! The axe metal is much harder than the average axe. Quite impressed.

I don’t think my logs would go in an electric log splitter.

Phil

Why should pitching them require planning permission? We are in an emergency and a lot has to give.
Here in Ireland the law is still that panels must not cover more than 50% of roof space. That ‘permission’ was ‘granted’ in 2007, restricted at the behest of the energy suppliers. We may be already too late, but we must maximise our use of Solar with no delay.
My consumption today is 14.9kw of which 12kw is from my roof, despite not much sun. I have also run completely off the sun during peak demand periods, due to my battery storage.
We need ‘foot to the floor’ on this!!

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What size battery are you running? Does it cover your peak demand periods in winter as well?

I understand if you raise the profile above a certain amount above one’s roof line. If you look up planning permission requirements for solar panels you will see the details.

Now on a slightly different but connected matter… how does one keep panels cool in sunny but hot weather… I was quite surprised the extent to which most current solar panels loose their efficiency and effectiveness when they get hot. It would appear smaller more efficient cells with shrubs or liquid between them is an answer. Having them closely side by side on a roof or wall appears a very bad idea with regard to hot weather performance and the local heating effect. This configuration optimum for sunny cooler weather, not sunny hot or very hot weather with current technology.

I guess we can expect see more on this in coming months, especially with greater understanding of local heating and heat hazard effects… we might need to rethink solar panel installations with climate change…. and current technology…

Perhaps spaced flexible panels on tree tops or a woodland canopy is an idea.

Hey Mike - That’s a good size system! We had to stop at 5KW with 20 panels otherwise any additional panels would have been sub-optimally placed which is inefficient I guess. From a Feb 19 installation we have now reached 28600 KW so roughly 23KW/Day. You should be cracking 35kW/Day with any luck!!!

You also get a very good feed-in rate @ .1438 kwh which is double what we get, that said we are paying a flat-rate 18 cents a kWh so I can’t complain. Good luck!

David

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Thanks David. Yes, it’s an 8.74kW system with 23 panels. 8 facing NE tilted on a flat roof over our kitchen, and 15 on the sloping main NW facing roof.

We could have squeezed in 2 more panels on the flat roof - we have micro-inverters, so it’s still an option, but will see how it looks after a year of use and maybe reconsider the option of a battery. I’m picking that the price of the barriers needs to come down, and power prices go up, to hit a reasonable cost/benefit return.

Yesterday, we were peaking at a production of 5.6kW, with 20.3kWh for the day. The forecast peak summer production is 48.4kW per day.

I’m really pleased we have done it. We work from home, so we can match our power use to the daytime as best we can. Our power plan also has a free hour of off-peak power a day, that you can change before midnight each day on their app. Now we have solar, I just check our use for the day and select a free hour of power. That’s pretty good for winter. Come summer we will have too much power and will banking those buy-back credits!

For me, I would say the peak generation is not that important. My peaks are up to 5KWh, but to be honest all I really need is about 3KWh which covers by 300W default house usage, plus allows 2.4KWh for things like kettles/Washing machine, etc. Anything above 3KWh doesn’t get used. Of course if I had an EV that would be different.

In practice, what’s far more important for me is what they generate in winter, which is when I want the best efficiency.

Your app is way better integrated than my Fronius. Our peak is 41 KWh; I am backing your system to peak at some stage +50…!!
I am resisting a battery for now because we have a really good flat rate 24/7, the cost per KW storage is off the scale, and we heat with gas… for now. When our planet-friendly Volvo petrol SUV is at least 4-5 years old I think it will make a lot of sense to replace it with an EV with a 70+ KWH battery that will offer 2-way power exchange. Our modest mileage will make using it as the house battery a very good option: we need more manufacturers to jump into power to grid transfer tech, or something like that…

The final piece of the jigsaw is to see if I can put a separate off-the-grid array on the sun-facing shed/garage roof to directly power the pool heater/pump thing when we put the pool in…

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Battery is 4.8 KW. When I refer to peak demand periods I am thinking in terms of the grid, rather than my own peak demand. I haven’t measured clinically, but I would say that I am effectively ‘off grid’ during the 5pm to 7pm peak about 90% of days, all year round.

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Has anyone here had solar panels installed on an outbuilding?

Whilst our house would be ideal as it has a large roof being a chalet house we’re not sure that we could tolerate the look of panels on the house. We’re coming round to the idea though that having panels could be beneficial.

Down the end of the garden we have modern a Comptons sectional garage. This is like the Marley garages of old with reinforced concrete walls bolted together on a concrete base. It has a steel A frame roof with concrete roof pitched at an ideal angle. The garage is 28ft long and 14ft wide so there’s quite a lot of roof area available.

I’m wondering if such a building could take solar panels?

It would require a long run of cable back to the house but presumably most of the other paraphernalia could be installed in the garage?

I can’t think of a reason as to why that wouldn’t work, as you say you just need a cable that will connect your inverter to your incoming power cables.

Solar panels can be mounted pretty much anywhere from a functionality viewpoint

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It sounds ideal really, provided there is a system for fixing the panels to the roof. What exactly do you mean by a concrete roof? Tiles?

Concrete isn’t really correct having looked it up.

They are called fibre cement roof sheets. Corrugated and pretty thick and heavy.

The garage is similar to this. It’s a double tandem garage which is wide enough that if you get a car dead centre you can fully open all the doors.

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