Who has solar?

Sangoma said:
I think a potential problem could be tax.
It won't be long before a hefty tax is applied to electricity used to charge EVs, which would mean if you have that tariff to charge batteries, you will be paying the extra tax on it.

I don't believe any government here is going to just lose the tax on car fuel :)
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How will they determine what the electricity is used for once it passes the meter? If they introduce metering of individual circuits, how would they determine that the power charging the EV is not coming from solar or a solar-charged battery, rather than from the grid?

So many problems to overcome to implement that.
 
FWIW, my ~5 yo EV charger Podpoint Wifi completely stopped working end of last month.
It reverted back to being a "dumb" unit, doesn't report usage to Podpoint app, cannot control it via schedulling. So if tax were to be based on reporting by "smart" EV chargers, do they then have to retrospectively make manufacturers fix all broken ones? 'cos I ain't spending money to fix this one small thing purely for tax purposes.

Just like the "start engine" button, range and re-fuel mentality, one cannot simply replace fossil fuel car with EV and do everything the same: "tax was charged on re-fuel, so we must add tax to the charging process"
 
So.....7 months since I started all of this and nearly 2 months since I *thought* it was all finished.....it's finished.

6k of solar in 16 panels split into east / west arrays, 7.2k of batteries running off an AC inverter and a Zappi to charge the Tesla :) We haven't (yet) fitted the iBoost to heat the water because our HW tank is old and fragile so fitting an immersion may break it.

Total cost was £11,250 for solar, batteries, all the fitting and far more wiring than I expected plus £1,174 for the Zappi. (Since I started this and fixed prices I believe they have gone up by at least 20%).

I'm currently on Intelligent Octopus paying 10p / kw between 23:30 and 5:30 and *a lot* during other hours - I missed the 7.5p deal because Octopus took so long to get the Zappi working (4 engineer visits to do what I said they needed to in the first place). But I'm actually selling surplus for 15p so it isn't too bad. Now the days are short, I set the batteries to charge overnight and pretty much never hit the grid in the day - everything comes from solar and battery.

Here's my Octopus power usage for October

1667290214110.png

That's 81KwH exported and 177 imported. Of that 177, >90 was to charge the car.

Here's what a day looks like (Octopus glitch export is from a day earlier than the import - it rained pretty much all day on the export day which is why following import is so high.)

1667290463738.png

In the summer I won't be hitting the grid at all.

If you can afford it and have the space, get it. If you don't have the space or money for a full install then look at batteries. I reckon for £4-5k you may be able to shift all your power to night time which will cut electricity bills by about 65%. That's a reasonably simple payback calculation.

Oh and don't get me started on how awful the app for a Solis inverter is. next step is Home Assistant. @wyx087 - I'll have questions :)
 
"Total cost was £11,250 for solar, batteries,"

I won't be around long enough to make a saving on that.

I'd have to break a few mirrors :)
 
Nice one. That's awesome you have a good solar install. I agree battery these days make a tonne of sense. Shift the usage to cheaper periods, help the grid and save money, it's win-win.

A quick search for Home Assistant Solis inverter, it doesn't look like it's a simple integration, need some DIY. https://community.home-assistant.io/t/communication-with-solis-inverter/292502/24

I've gotten past the first filter for Indra V2H trial. https://www.indra.co.uk/v2h
This is £1600 for Nissan Leaf V2H charger/inverter. Then I'd effectively have access to ~18 kWh of battery on my driveway. Then I should be able to achieve similar to what you are doing, storing my solar excess production and time-shifting my usage to 7.5p cheap periods.
Total cost for me: £7000 for 2.9 kW-p solar install back in 2015, £1600 for 6 kW inverter to access car battery, £8900 for second hand EV in 2017 = £17,500 for home energy and mobility.

I've nearly got return-on-investment for the £7000 solar panels. £8900 for EV, driven 40k so far at ~3p/mile, saving 10p/mile over a very efficient diesel means saved £4000 on fuel alone, so far! £1600 for V2H inverter will need less than 2 years for payback based on time-shifting usage alone, not counting free energy from solar.
 
JonathanRyan said:
In the summer I won't be hitting the grid at all.
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So....just over a year since I started this thread and just under a year since the panels went on the roof. If you've been keeping up with the thread you'll know that it basically took all summer to get the batteries and then a lot more faffing to get everything sorted with the Zappi (I skipped over many amusing tales of CT clamps in the wrong direction....) and finally, almost when I could have predicted it, we're there.

Screenshot_20230507-154405.png
That's my entire electricity bill for roughly April (the overnight rate changed on 21st hence the 2 lines).

Including standing charge, all usage including charging my car (100% home charged) my bill for the month is minus £35.71. Which is roughly what I expect my gas bill to be because we still don't have an immersion. So for April I'm paying roughly 0 overall. I'll expect to make money in May - August, break even in September and pay a little for the rest of the year. That's compared to about £150 dd a month. So payback now looks to being somewhere around 6-7 years and I get free motoring. Though of course the Tesla wasn't cheap :)
 
Is that payback including the fuel savings you're making now your charging is free?
 
OP got EV after solar, IIRC. The £150 a month is most probably without EV consumption in the bill. £150 pm for 7 years is over £12k, about price of his system.

So adding in EV equivalent fossil fuel cost will see the payback period slashed greatly. But I'm not sure people would calculate that way, because most people would switch to EV focused tariff for cheaper off-peak and gain 2.5p/mile instead of using 10-16p/mile in fossil fuel cars.


I'm so jealous of OP's larger solar install. I've only got a 7 years old 2.9 kWp W-E, no Zappi, no battery. But here is me using Tesla API and my own software solution to achieve something similar in a slightly cloudy day, recharged 5% into the battery zero cost. Goal is to charge the car and export as little as possible because I am on old feed-in tariff and have deemed 50% export payments.
1683493855605.png
 
I know but he had petrol/Diesel costs before he got his Tesla. I was just wondering if he had factored his fuel savings into his payback timing.
 
Nod said:
I know but he had petrol/Diesel costs before he got his Tesla. I was just wondering if he had factored his fuel savings into his payback timing.
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No I didn't.

My quick calc was my DD was set at £150 / month. I'm aiming for roughly a zero fuel bill for the year so 11,000 / (150 * 12) = 6.11 or 6 - 7 years (though fuel is only likely to go up).

I didn't factor in the fuel costs of my Honda Estate because then I'd have to factor in that the Tesla was really really expensive :) Financially it was almost certainly not worth it, but it's so nice to drive.
 
And I reckon RHD ones will hold their money pretty well too!
 
Very nice. you are a net-producer home.

Meanwhile, I've used Home Assistant automations to allow me to drive on sunshine:
www.speakev.com

Charging off excess solar using dumb charger and Home...

www.speakev.com www.speakev.com

For me, I get "deemed export payment" meaning I on top of feed-in tariff for generation, export is assumed to be 50% always. So I have incentive to export as little as possible. About a third of the mileage I've done over last few weeks had been powered by sunshine.
 
wyx087 said:
Very nice. you are a net-producer home.

Meanwhile, I've used Home Assistant automations to allow me to drive on sunshine:
www.speakev.com

Charging off excess solar using dumb charger and Home...

www.speakev.com www.speakev.com

For me, I get "deemed export payment" meaning I on top of feed-in tariff for generation, export is assumed to be 50% always. So I have incentive to export as little as possible. About a third of the mileage I've done over last few weeks had been powered by sunshine.
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I'm about to lose deemed export as I have a smart meter and the FIT provider (Good Energy) has told me now it has the data from that it's going to pay my actual export, which is more like 10% of my generation across a year than 50% :(
 
onomatopoeia said:
I'm about to lose deemed export as I have a smart meter and the FIT provider (Good Energy) has told me now it has the data from that it's going to pay my actual export, which is more like 10% of my generation across a year than 50% :(
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Do you have home storage?

I'm also with Good Energy and they informed me of this a few months ago. Because I'm getting V2H installed soon, which is a form of home storage, the rule says I cannot be switched over to metered export. I've got confirmation from Good Energy after sending them a schematic.

Check out this thread, other people in similar situation had success staying on deemed because have home storage:

Stupid, I know. People who later installed home storage are able to stay on deemed 50% export, effectively never export and still get paid as though exported 50%.

JonathanRyan said:
We will be in a couple of hours :)
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Why does the screenshot show 0 self-consumption?
Out of interest, what tariff are you on? What do they pay you for each kWh exported?
 
wyx087 said:
Why does the screenshot show 0 self-consumption?
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I really don't know - the Solis app is......unusual. I don't really use it or anything other than checking SOC - MyEnergi gives me a much better view of what's going to / from the grid.. I think it's misreading the self consumption due to a clamp somewhere or a strange interpretation of self -consumption. But now that everything I care about works I've never looked at it :)
 
onomatopoeia said:
I'm about to lose deemed export as I have a smart meter and the FIT provider (Good Energy) has told me now it has the data from that it's going to pay my actual export, which is more like 10% of my generation across a year than 50% :(
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We are with good energy as well and the FIT payments we get are pitiful :(
One would have thought that with the rise in electricity prices the FIT payments would go up, well it seems not.
 
Several neighbours have had panels installed in the last few months, none so far have boasted about hugely* reduced bills so I’m hanging back, all 8 have used different installers so no guidance there either.
I did enquire using wind power but seems planning regs here means no neighbours for 50 yards, that idea is down the pan then, probably one of the few advantages of staying on high ground gone, still, we’re unlikely to suffer from flooding.
*or even slightly.
 
mj4456 said:
Several neighbours have had panels installed in the last few months, none so far have boasted about hugely* reduced bills so I’m hanging back, all 8 have used different installers so no guidance there either.
I did enquire using wind power but seems planning regs here means no neighbours for 50 yards, that idea is down the pan then, probably one of the few advantages of staying on high ground gone, still, we’re unlikely to suffer from flooding.
*or even slightly.
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There is an article in the latest edition of the Centre for Alternative Technology's magazine looking at personal wind turbines and to paraphrase, the outcome was "don't"!
 
Seemed like a good idea because we rarely have a ‘still’ weather day, and looked less faf the solar, ah well.
 
jerry12953 said:
We looked into it as well, as we're on the top of a normally very windy ridge. But I think you need quite a lot land as well, so that you can getthe turbine away from the house (yours and everyone elses) .
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Yes. As far as I can see right now, wind turbines only make sense for groups of people. To buy one bigger than a caravan one costs serious money and as you say needs a lot of clear space. The ROI isn't currently there for a single property.

mj4456 said:
Several neighbours have had panels installed in the last few months, none so far have boasted about hugely* reduced bills so I’m hanging back, all 8 have used different installers so no guidance there either.
I did enquire using wind power but seems planning regs here means no neighbours for 50 yards, that idea is down the pan then, probably one of the few advantages of staying on high ground gone, still, we’re unlikely to suffer from flooding.
*or even slightly.
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It can take longer than you expect to "see" the savings. See some of the posts in this thread and then imagine all the ones I spared you :) They will need a DNO and G98/99 notice before the electricity company will start payments. There can also be a lag between bills so I would expect it to be 3 months or so before they notice a difference - then the difference will effectively be backdated.

It's the longest day tomorrow and export is currently 164 kw > import so we're on track to be a net generator of electricity this year including motoring. It's touch and go whether that relates to a negative bill overall or not because of differential pricing and standing charge but we should have a much reduced bill this year.

In other solar related news....I got sick of all the spam emails from Octopus about heat pumps so despite my prejudices I asked them for a quote. I was very pleasantly surprised with a figure of £6.900 all in - including a brand new hot water cylinder (so I can run the HW off solar at least in the summer). Then I mentioned I had microbore and they said it would be an extra 5k for a repipe which may well go up when they find out what lovely floors we have......
 
So.....just spent a little time with Excel to work out how my first full (Jan - Dec) year has gone. The disappointing news is I don't *quite* live in a power station ;(

For calendar year 2023, I imported 3,808 kwh and exported 3,655. So I net imported 153 kwh to run my entire house and all my motoring (all charging was done in house). Sadly, I don't have electric heating/cooking and for reasons I have to heat all my water via gas so I also used 4,660 kwh of gas.

Looking at the costs is slightly more cheerful reading. It's complicated because of different billing cycles and incentives Octopus use and there's also the HMG subsidy from last winter to take into account. But.....gas cost me an alarming £655.88 for the year. Electricity cost me minus £76.21 but I also accrued 45.659 Octopoints which I can trade in any time I want for £57.07 so I'm going to claim that Electricity including all motoring cost me minus £133 for the year. At standard tariff, standing charge + 3,800 kwh of electricity would have cost me £1,350. Without working out how much I used overnight excluding house batteries (and that's too much geekery even for me) it's hard to say what I would have spent but back of an Excel tab suggests that I have another 6ish years to go before they have paid for themselves.
 
I have something strange happening with my system
It went off , Dead , Flat battery , I noticed this and did a re set , All back and running.
Some time later I noticed my smart meter was showing Amber, Strange what is causing this , I went round the entire house switching everthing off , It still showed amber ? Humm strange,
Then the penny dropped , what is happening now , At 9.45 am the inverter is acting as a battery charger and using mains electric to re charge my storage battery at import KWH price
Then if the sun comes out the energy collected can't go into my battery so goes into the grid at the export price , Yes a lot less , So I am being charger import tarif to charge then export tarif for my export , What I would like to know is who controls my inverter ?
 
Do any of you have gateway or similar, which ensures you never feel effect of blackout?

Even though I have V2H and solar, all are grid-tied. Grid power cuts and I am still living in the stone ages.

Come February, fitting batteries by itself will also qualify for 0% VAT. So I'm considering getting something like Tesla powerwall with gateway or GivEnergy AIO with gateway. But will probably wait a few months so installers will be less busy.
 
wyx087 said:
Do any of you have gateway or similar, which ensures you never feel effect of blackout?

Even though I have V2H and solar, all are grid-tied. Grid power cuts and I am still living in the stone ages.

Come February, fitting batteries by itself will also qualify for 0% VAT. So I'm considering getting something like Tesla powerwall with gateway or GivEnergy AIO with gateway. But will probably wait a few months so installers will be less busy.
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In South Africa that would be great, almost essential for those who can afford it. My kids sometimes have power for less than half the day.

But with reference to grid power cuts, in the UK I don't see it being worth the cost.
Most homes would not have enough solar cells to fully recharge the battery on dull days.
The frequency and duration of power cuts is very low here, we have a back-up generator, and it has been used once in 22 years for a power cut.

We have 12V lighting through the house, and ability to run the boiler from an inverter for heating and hot water, and without the generator could keep going for 3 days without power.
I installed this a couple of years ago when the likelihood of short duration cuts became greater.
A cheap and simple answer, proportionate to the possible and currently likely inconveniences,
When the national grid starts collapsing, which looks like in about 7 - 10 years at the current rate, we will look again :)
 
wyx087 said:
Do any of you have gateway or similar, which ensures you never feel effect of blackout?
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I have a powerwall and the gateway ensures it doesn't send 240V back to the grid during a powercut, so it can still power the house without electrocuting the person from the DNO working on fixing the cables down the road, unlike most battery systems which can't isolate so would just pump the power back out to the grid.

It works, with caveats. One is the maximum continuous power it can supply which I think is around 4kW, so no taking an electric shower, the other is there is a fraction of a second of outage during the switch from grid to battery so it won't stop the clock on the oven needing to be reset or your router from restarting, and most likely any computer that is powered on from being forcibly rebooted (some will have enough capacity in the capacitors in the power supply to survive). I also have a UPS behind my server for this specific reason.

It was certainly useful at Christmas when there was a two hour grid failure at 10am on the 25th for 40 properties here including mine, then others of similar length on the 26th and 27th. I generally get about one grid failure a month on average here so it's definitely worth it to me.

One thing that has to be considered is the amount of charge you leave stored in the battery to handle extended outages, particularly at this time of year when there is limited sun for solar charging.
 
The Tesla powerwall contains AC inverter, so presumably the UPS function will maintain the grid-tied solar inverter?

I have grid-tied V2H on my Nissan Leaf. I'm wondering if I can keep it functioning during a power cut. This would mean if the grid collapses :ROFLMAO:, I can carry electricity from public charger to use at home.

Living in Greater London, power cuts are indeed very rare occurrence, about once every 10 years for a few minutes at most. But it's really annoying to have installed all those hardware to still sit in the dark.

Yes, UPS on sensitive equipment is still required. The equipment with longer the switch-over time (to a few seconds) understandably are slightly cheaper.
 
Sangoma said:
You will have to put another couple of foot of insulation on your converted telephone box :)
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5 bed detached built with 80s "insulation" actually :) we have a lot of sweaters.
wyx087 said:
Do any of you have gateway or similar, which ensures you never feel effect of blackout?
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I don't. I looked at this and with the rareness of power cuts here it didn't seem worth the effort. I'm looking into upgrading the house fuse and it's possible that would be a good time to add something.
 
We have a south backing garden but as the house is a chalet style the roof area, even if we wanted it could justify PV panels is not that large.

However, I have wondered about a UPS especially with the impending switch to Digital Voice.

Therefore, a quick question to you guys using a UPS, what make and model have got & do they now use Li-ion or are they still 'sealed lead acid batteries ' ???

TIA :)
 
wyx087 said:
The Tesla powerwall contains AC inverter, so presumably the UPS function will maintain the grid-tied solar inverter?
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If you mean does the inverter still work during a power cut then yes it does, to supply the house from either the battery or panels or both depending on demand. If there's no grid, no sun and the battery is empty it doesn't.
 
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