The Solar Thread

4kW east/west array in North Yorkshire. Tends to do OK in the morning if it’s bright but significant drop-off in afternoon as the sun goes behind a line of tall trees. It doesn’t cover the roughly 4kWh daily draw of the house, but it’s still pretty rare to end up with empty batteries when I go to bed.

Heat pump tumble dryer helps with this and will largely run off solar provided it’s not raining.

Panels go above 200W at 8am, peak at about 800W at lunchtime, and are offline at about 3.30pm. Weather has been rubbish for weeks now though. Having said all that my net balance with Octopus is £140 in credit with the direct debit set to £1. The £200 oil credit means that I’m cost-neutral for energy this winter (if it ever happens, I can’t see any realistic way of implementing it).

So we now have a solar system installed, 9 x 425 Watt panels plus 10 kWh battery..

Solar panels on south facing part of roof by Ben Freeman[/url], on Flickr

Solar panels on South facing part of the roof by Ben Freeman[/url], on Flickr

10 kWh battery and inverter by Ben Freeman[/url], on Flickr

I seem to recall some public website where you can link your system to and it tallies up everyone’s generation (of those who have connected) – does such a thing exist?

That’s a really tidy precise install ! No margin for error on that roof.

That’s a really tidy precise install ! No margin for error on that roof.

They were very good, the electrician was very tidy on cable runs etc.

The roofers were tidy as well – lovely under tile brackets:

Solar install by Ben Freeman[/url], on Flickr

Solar install by Ben Freeman[/url], on Flickr

Solar install by Ben Freeman[/url], on Flickr

Solar install by Ben Freeman[/url], on Flickr

They also replaced every cracked tile with a brand new slate one – which is impressive given no one would probably notice…

So mines installed and up and running. looks a little like this

https://photos.app.goo.gl/GwUXYEG8cnMhuUjQ9

Its got 11x 400W Ja pannels with a luxpower hybrid invertor and US5000 pylontech battery.

So far so good but since install its not been giving a lot (weather) on average its pulling in about 200W at any one time between 10am and 3pm. this just covers the house base load. this gives about 1.5KW a day. i was hoping that it might be able to power an immersion heater during winter but this clearly isn’t the case

The battery is interesting as im looking to use it to move some of our dependence outside of peak. but not enough to make me move tarrifs yet.

Best thing is the energy monitoring. its really interesting graphing the usage but unlikely to get me to stop using anything.

looking forward to the summer.

I seem to recall some public website where you can link your system to and it tallies up everyone’s generation (of those who have connected) – does such a thing exist?

pvoutput?

. i was hoping that it might be able to power an immersion heater during winter but this clearly isn’t the case

Obvs this depends on what you’ve got running in the background in the house – I saw some immersion activity* a couple of days ago.
Basically the winter is a bit crap though. I’m still looking to add a separate 2Kwp ground mounted array set up to maximise winter production.

* Top tip. If your immersion diverter does not have an always on display fit an immersion switch with an old school filament bulb in it to give an immediate view of what’s happening.
It will light dependent upon how much power is going to the immersion (i.e. flickering dimly up to a solid bright light).

pvoutput?

That looks like it, just need to figure out how to get it to talk to the Huawei system….

. i was hoping that it might be able to power an immersion heater during winter but this clearly isn’t the case

Our predicted generation is only 1Kwh per day in December, so unlikely to be able to heat much water.

We have bought an Eddy Power Diverter for the immersion, but that hasn’t been installed yet.

I do mine with a Raspberry Pi talking to the inverter with a python script and then uploading data to pvoutput every 5 minutes.

We’re having a new, south-facing roof built on an extension next year, which at some point (probably 6 months later, due to finances) we’ll have solar added to.

We’re thinking about having the builder put countersunk solar panel holders on (ratehr than brand new tiles that then have a solar panel whacked on top of them) as they build the roof. I know that these marginally effect peak output due to heat, but we’re not too worried about that.

How much varience is there in panel sizing? what we don’t want to do is have a bunch of holders put in then be stuck with availability of panels, either when we go to put the panels in for the first time, or if we need to replace a panel down the line..

I do mine with a Raspberry Pi talking to the inverter with a python script and then uploading data to pvoutput every 5 minutes.

Yes, just found a project on GH, was hoping I wouldn’t need a local host to run something and could just connect PV to Huawei direct via an API. Will have to get a Raspberry PI….

How much varience is there in panel sizing? what we don’t want to do is have a bunch of holders put in then be stuck with availability of panels, either when we go to put the panels in for the first time, or if we need to replace a panel down the line..

Panels vary a lot eg ours are different to the neighbours ones. However, the panels are clamped to rails, with ‘over the lip’ clamps, which means there is some flexibility to accommodate panel size variations on the same rails.

Solar install by Ben Freeman[/url], on Flickr

Fitting clamps:

Solar install by Ben Freeman[/url], on Flickr

Nest guard? Couldn’t obviously see any on the recent install pics.

Did you go for optimisers?

Considering theses options at the moment for an install.

Did you go for optimisers?

AIUI you only need those if you expect partial shade on the panel array.

Nest guard?

Wasn’t suggested nor offered, so no.

Can’t see any nests on the neighbour’s arrays..

@footflaps – they’ve done a super job. You must be happy with how the panels are presented?

Nice set up and i like the Python script element. I have some panels going onto one of my outbuildings in the next couple of weeks to service the home office. I have the Powerwall set up for my house, but have opted for an SLA battery cluster so will enjoy getting this working with the Pi.

@footflaps – they’ve done a super job. You must be happy with how the panels are presented?

Yep, they were very slick and have done a very neat job.

One of our neighbours had some cowboys in to do hers a few years back – they just drilled through the slate roof into the rafters shattering all the tiles in the process. It then rained and the roof leaked like a sieve. She spent about 2-3 years with tarpaulins all over the roof and eventually sued them for a new roof. Her install was finally finished by another company earlier this year!

Nest guard?

Wasn’t suggested nor offered, so no.

Never had an issue with birds on either of my arrays so I’m not sure it’s actually a thing (similar to cleaning the panels)

Did you go for optimisers?

AIUI you only need those if you expect partial shade on the panel array.

Yep and if you have a split array (E/W for instance) then you can just fit an inverter that takes multiple strings. They also add a layer of complication: on the one hand if one goes down then you just replace one optimiser rather than a more expensive inverter. But, generally, inverters are easy to get to and replace while optimisers involve getting onto the roof and finding which one has died before you can replace it – hard work , tricky (especially as panel removal is possibly involved), and spendy!

Useful thread this. We’re having the roof off next summer and planning to fit flush panels (18 of) with inverter/10kw battery. The way our house is orientated it gets sun on one side of the roof in the morning and then other roof in the afternoon (it’s an odd shape but it’s a big roof so we can fit lots of panels).

It was interesting working out how many panels we should go for. But as we have no gas, no oil (ground source only and elec cooking) we were going to be better off with ‘quite a lot’. Along with proper roof insulation, new windows upstairs, fixing the other roof (long story) and reboarding/insulating the house length loft we’re hoping for significantly less use of main supply – esp outside winter.

I’m really looking forward to mining the data 🙂 We might not get a return in the 10 years we intend to stay here but it just feels the right thing to do for whoever has the house after us as well.

Now trying to align roofer/builder/solar installers at the same time is going to be fun….

then you can just fit an inverter that takes multiple strings.

Our inverter takes two strings and they split the 9 panels into a run of 5 and a run of 4.

I didn’t ask why they just didn’t have one string – I guess having two means it works slightly better with partial shade eg clouds?

We might not get a return in the 10 years we intend to stay here but it just feels the right thing to do for whoever has the house after us as well.

I did the sums on ours, approx 20 years payback at 28 pence per kWh – so not a great business case….

Obvs this depends on what you’ve got running in the background in the house – I saw some immersion activity* a couple of days ago.
Basically the winter is a bit crap though. I’m still looking to add a separate 2Kwp ground mounted array set up to maximise winter production.

yea im taking it into the battery atm. no immersion heater or divertor installed at the moment. Im going to see how summer goes.

I didn’t ask why they just didn’t have one string – I guess having two means it works slightly better with partial shade eg clouds?

Yep, without it a couple of shaded panels could bring your output down considerably. It also means that a fault on one part of the string does not stop your entire production.

yea im taking it into the battery atm. no immersion heater or divertor installed at the moment. Im going to see how summer goes.

From April/May our PV produces all our hot water – it’s a great use of PV.

i was hoping that it might be able to power an immersion heater during winter but this clearly isn’t the case

I have an iBoost which heats the immersion from spare solar once the battery is charged. I have been fully charging the battery during the Eco7 period which ends at 7:30. Between 7:30 and 8:30 the battery takes a hit then generally tops itself up depending on the solar. Yesterday it topped up fully by around 10:30 then heated the water fully an hour or so later then I did a bit of cooking and a slow pot for tea, washed some clothes and ran the tumble dryer for an hour. The battery was around 100% when the sun went down and I had sent a couple of kW back to the grid (15p per kW) All good on a winters day but other than the iBoost and grid feed it does require me to monitor to take advantage.

The issue for us is the early evening use. If we use the oven and electric hob for more than a short period we are running out of power around 8-9pm. Our battery is 8.7kw but with 90% usable. Another battery module would sort it but at £1500 I am reluctant just to save a kW or 2 a day in winter. Once we have even an hours more of daylight the problem will disappear.

So far I am happy with the investment even in November… A large upfront cost however..

I did the sums on ours, approx 20 years payback at 28 pence per kWh – so not a great business case…

Yeah having looked at the quote, we’re not even going to get that! Ours is quite a big system tho

GSE in Roof System, 18x Panels on two roofs. (10 at road side and 8 on rear roof).
Huawei Optimisers with 6kW Inverter and 10kW Battery Storage.”
The panel area will measure about 19.2M2 on the rear roof.
The panel area will measure about 24M2 on roadside roof.

We also have ground source with the facility to plug solar into the immersion, but the advice we’ve had from multiple experts is that’s not a good use of the power compared to a battery.

If we can get the farmer to chop the trees down on the other side of the road before they fall INTO the road, our afternoon panels will see quite a lot of sun. Still he’s only been promising to do that for the last 9 years so maybe next year 😉

@footflaps

Is your battery outside? Is the capacity not affected by cold?

Yesterday it topped up fully by around 10:30 then heated the water fully an hour or so later then I did a bit of cooking and a slow pot for tea, washed some clothes and ran the tumble dryer for an hour.

So what was your generation yesterday?

but the advice we’ve had from multiple experts is that’s not a good use of the power compared to a battery.

If you have a battery then the spare generation should go there – otherwise send it to the ‘water battery’

If we can get the farmer to chop the trees down on the other side of the road before they fall INTO the road, our afternoon panels will see quite a lot of sun.

Oh the irony!

@sharkbait – we need to see what’s left before deciding on some extra plumbing. It’s not ideal in terms of location of pipes. But I anm stealing water battery 🙂

In terms of trees, just to be clear our lane is sunken, the three trees are dead/near dead on the opposite bank. One already fell into teh road and just missed next doors house! I’m not advocating hacking down healthy trees as part of a greener energy solution!

So what was your generation yesterday?

Try to look later. I have a Foxess system and the software is not intuitive. I will be installing home assistant at some point which gives more data. I am out at the moment but my pv is providing >3kw right now.

Councils around here are having a purge of overhanging trees on safety grounds, especially as there is so much Ash die back in the area. I recently got a snotty letter from the council informing me of my legal obligation to ensure there are no branches or trees at risk of falling on the road. I was able to smugly reply that I have no roadside boundary whatsoever so they should direct their request to the correct landowners 🙂

So might be worth raising a query with your local council highways dept if you really do feel the tree represent a hazard. If there are any dead or dying ash trees there I bet they will be removed pronto!

Thanks Matt. I wrote a longer reply but the forum ate it. Short version- farmer is a lovely fella, he will get round to it, he has lots of the councils tree cutting contracts so he’d probably get a letter to himself asking him to clear the trees. I will take a look to see what the trees are – never bothered as they are covered in ivy.

I’ve just seen this thread! We have a solar + battery on order – 4.68kW solar panels and an Alpha ESS battery.

Seems that the Alpha ESS batteries have a supply-chain problem so we’ve been offered alternative batteries – Solax or Givergy. I use Home Assistant and have read that Alpha ESS doesn’t easily allow web data scraping. Has anyone got either a Solax or a Givergy battery? Any good?

We have a 10kwp roof – roughly 35% east, 65% west facing. Great for 9 months of the year, useless in the winter. Even on a bright sunny day like today, we’ll be lucky to get 7 or 8 units for the day. Most days are closer to 4. Since we are an electric-only house, it doesnt go far.

Have just managed to persuade our provider, utilita, to shift us to Economy 7. They wouldn’t before for some reason, but seem to be amenable now. This will hopefully mean we can use the overnight window to heat the floors, hot water and, importantly, charge the 10kw battery. If this system works, the battery alone will be a £2.50 a day saving versus current costs, and heating etc will save loads more (on a bad day, with a house-full we used 80 units last xmas).

We don’t have an EV, and this tariff isn’t designed for that, but i don’t see any restrictions in the T&Cs.

Will change again in March as they only pay 3p/unit export.

@sharkbait

So what was your generation yesterday?

Circa 7.3kW which is pretty good for December and more than I expected although I am sceptical of the stats from the Foxess web/app. Its a realistic number though as I did all of the above, had a full battery when the sun went down and hadnt pulled anything from the grid since 7:30.

That’s impressive given the lack of daylight at this time of year. I presume your array is fairly big (missus)!

5.6kW

@footflaps

Is your battery outside? Is the capacity not affected by cold?

Yes, and probably a bit, but if they had put it in the attic – it wouldn’t be much warmer….

We’re getting 3 kWh a day when it’s clear (array is 3.8 kWh max). At the low angle we’re getting shadowing from next door’s chimney which is probably nobbling it a bit, plus the second row never clears partial shadow. I do wonder whether adding optimisers whilst the scaffolding is still up might be a good idea….

Solar array by Ben Freeman[/url], on Flickr

Solar 0912022 by Ben Freeman[/url], on Flickr

Another winter day reference point, 4kwp south array, North Yorkshire, 7.7kwh generated today, almost all day blue sky, little bit of light cloud an hour or so early afternoon. Just under 6kwh to HW as we have been out most of the day, just the dishwasher ran around midday.
At 7 years, I do think my panels are starting to drop in performance mind.

Well, It’s all finally installed with the battery having gone in today and the array having its G99 Approval given 3 weeks ago after having been installed in Mid September.

5.5kWp Array – 13kWh Battery. In 19 days of operation (since November 21st) we’ve generated 115kWh (the period of unending fog really killed it) with just over 10kWh today. Not too bad given that almost the entire lower 1/3 of the array is in shade until 11:00AM.

5.5kWp Array – with just over 10kWh today.

That suggests ours is under performing – 3.8 KWp array, so 60% of yours, but only 3 KWh today and a pretty clear day…

test! Can’t seem to reply to thread!