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Solar Panels UK - is it worth it?

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whats your worst ‘average’ case (so not extremes)? Eg winter, cloudy week, cold. Your HP won’t be as efficient so will need more power, and maybe not so much generation. will off peak battery charging cover you through higher energy usage and little/zero solar, or do you estimate some level of peak usage for those times?
 
whats your worst ‘average’ case (so not extremes)? Eg winter, cloudy week, cold. Your HP won’t be as efficient so will need more power, and maybe not so much generation. will off peak battery charging cover you through higher energy usage and little/zero solar, or do you estimate some level of peak usage for those times?
naa, no chance. The HP soaks up ~40kw on a really cold day, and the PV could generate as little as 0.8kwh over the day in Jan. Average of Jan is more like 4.3kw, + 10kw of off peak used in the morning, saving 14kw of peak time usage. The heat pump consumption is both daily and seasonally opposite of the PV - my focus with the PV is to (conceptually) cover that 10kw baseload as much as possible, and continue insulating to reduce the HP usage.

Currently have filled cavity walls, but looking to put external insulation on too. Should bring the U value down from 0.3 to 0.17, saving another chunk each day (I have the calcs, but I think they may be wrong...)
 
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Is solar worth it?
Yes I believe so, but it depends on location.
Yesterday, Aberdeenshire 5.6kWh solar panels ( inverter limited to 4kW) into 17.5 kWh pylontech batteries running the house and 9kW Samsung heatpump all day. The peak is a small charge for the car. Saying that with complete cloud cover today the batteries will run out after about 12 hours.
Red:Grid Orange: solar Blue: Batteries
 
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Yea, looking at my 'good day' and setting the battery as if it had had the same good day the day before does create a lot of excess :(

View attachment 770585

That is indeed 22kwh exported :(. Baking? Cake is nice and must use some power?

Haha... well funnily enough 'baking' can be applied to you, as well as cake mix 😁 ... which is why we had a reversible air-to-air heat pump.

During repeated hot weather days (and they do happen even in the UK), we reverse our heat pump for Air Conditioning. So the excess solar can be trimmed to provide cool air comfort in the house, especially during the night time (again, decent battery storage powers this with stored Solar, so the batteries remain low ready for the next day sunshine topup).

During the day time, mid day peak (maximum generation) can be exported into the cars, but only if they're at home plugged into the charger. So there's nothing to export to grid 👍... if the cars are not at home, we then rely on our 27kWh Tesla storage batteries to soak up that excess, then we charge the cars from those when we get home.

Finding creative ways to salvage peak Summer power can be interesting, rather than just keep exporting it for very low return.
 
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Interestingly, I think I could potentially save more using an eco 7 tariff that runs through to 7am as it covers an extra 3 hours of background power and the heatpump firing up to bring the house up from night time temp (18degC) to day time temp (21). With that on 'cheaper' power the battery and solar can then cover much of the rest of the day and evening on an average day, only dipping into the grid late in the evening.

Comes down to the exact tariffs available and the amount of charging the car will need (and how much we can use solar in the summer), but I think the e7 actually works out better. At least at [email protected]/30p vs 7.5hr@15p/21p.
 
Interestingly, I think I could potentially save more using an eco 7 tariff that runs through to 7am as it covers an extra 3 hours of background power and the heatpump firing up to bring the house up from night time temp (18degC) to day time temp (21). With that on 'cheaper' power the battery and solar can then cover much of the rest of the day and evening on an average day, only dipping into the grid late in the evening.

Comes down to the exact tariffs available and the amount of charging the car will need (and how much we can use solar in the summer), but I think the e7 actually works out better. At least at [email protected]/30p vs 7.5hr@15p/21p.

Six hours of Intelligent? 23:30-05:30 guaranteed off-peak plus possible additional slots outside of this window.
 
Haha... well funnily enough 'baking' can be applied to you, as well as cake mix 😁 ... which is why we had a reversible air-to-air heat pump.

During repeated hot weather days (and they do happen even in the UK), we reverse our heat pump for Air Conditioning. So the excess solar can be trimmed to provide cool air comfort in the house, especially during the night time (again, decent battery storage powers this with stored Solar, so the batteries remain low ready for the next day sunshine topup).

During the day time, mid day peak (maximum generation) can be exported into the cars, but only if they're at home plugged into the charger. So there's nothing to export to grid 👍... if the cars are not at home, we then rely on our 27kWh Tesla storage batteries to soak up that excess, then we charge the cars from those when we get home.

Finding creative ways to salvage peak Summer power can be interesting, rather than just keep exporting it for very low return.
Your setup sounds brilliant for down south - no real need for cooling up here tho. Maybe a week a year it would be nice, and the HP could have done it, but it needed more expensive and less connected control system - wasn't worth it for the use we would get. We do have a portable aircon we wheel out when needed, but the extra insulation in the roof has very much reduced our need for it,
 
Your setup sounds brilliant for down south - no real need for cooling up here tho. Maybe a week a year it would be nice, and the HP could have done it, but it needed more expensive and less connected control system - wasn't worth it for the use we would get. We do have a portable aircon we wheel out when needed, but the extra insulation in the roof has very much reduced our need for it,

Yep, every home is very different...

I've invested on the basis of more 'extreme' weather in the future.

If we get a very hot Summer, then we're covered.

Lots of talk about temps rising, heat stroke killing people etc... so it made sense in my Man-Maths 😁
 
One question I haven't been able to get answered reliably (and the Powerwall owners might be able to help me with!)

How do you stop the Powerwall draining into the car when you plug the car in for a charge?

i.e if I get a home solar setup with Powerwall, the solar charges the PW during the day, powers the house at night.
When I plug in the car at 2030 for the Go faster, I'd want the car charger to draw from the grid only and not the battery.

Is there a setting on PW that it doesn't discharge during off peak?
 
You configure the off-peak period(s) into the Powerwall in this scenario. During that period, the Powerwall will not discharge.

Actually, it's not quite that simple from my observations. The Powerwall usually downloads some angry pixies during the off-peak period. At some point, the algorithm decides it has enough charge to last until sunrise. At that point it will either sit idle, with the house powered from off-peak grid electricity until the off-peak period ends, or it'll immediately switch to powering the house from battery.

There doesn't seem to be any pattern to the above behaviour, but I've never (yet) seen the Powerwall discharge into the car during the Octopus Go period (I monitor Powerwall and charger very closely using HomeAssistant).
 
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How long do you have to wait for a tesla installer to make contact after going through the website? Thought I'd kick that off for a quote while I wait for so.energy to pull their finger out.
I understand that virtually all solar supplier/installers are overwhelmed with enquiries in light of the rapidly rising energy costs. I’d start looking around and contacting suppliers direct rather than wait.
 
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One question I haven't been able to get answered reliably (and the Powerwall owners might be able to help me with!)

How do you stop the Powerwall draining into the car when you plug the car in for a charge?

i.e if I get a home solar setup with Powerwall, the solar charges the PW during the day, powers the house at night.
When I plug in the car at 2030 for the Go faster, I'd want the car charger to draw from the grid only and not the battery.

Is there a setting on PW that it doesn't discharge during off peak?

How I do this...

On the car cabin screen, I set the scheduled charge time to mirror my Octopus Go Tariff. So configure it to charge between 00:30 - 04:30

Then on my 7kW Zappi charger, I set this on Fast Charge and "avoid battery drain" and then leave it at that.

So when I plug the car into the 7kW charger during the day, the Zappi Car charger sits there "awaiting EV to start charging" ... nothing will happen until the Car's schedule starts charging at 00:30

The Powerwalls on the Tesla App are on Time Based Control, and have a dual-rate Tariff setting. 00:30 - 04:30 off-peak rate.

At 00:30 the Powerwalls start charging, and the Car starts charging... all at the same time, both from the Grid at cheap rate.

During the daytime, the Powerwalls now take in all the Solar during the day, and power the house only.

If I want to charge the car during the day from free Solar Power, I plug into the 7kW charger, manually go into the App and select 'Start Charging'... because we have Two Powerwalls, they can discharge at 10kW continuous so the car gets the full 7kW from the Powerwalls... until it stops at the charge percentage I've set.

In the background the Solar Generation continues to fill the Powerwalls at whatever power they're generating. It's not restricted to the 1.4kW minimum limit.

Now, if I want GRID ONLY during the day at peak rate, I use my second Zappi 22kW charger, which is connected to a 3 phase distribution board. Nothing to do with the Powerwalls or Solar. So that unit just rapid charges from grid only, night time at cheap rate or day time at peak rate...

Just depends which charger I want to use, how fast, or where I want the electricity to come from.

Having two EV Chargers at home also gives me a failover option if one breaks down.
 
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In the past, I used a very crude method of charging from the Grid during the day... if it was an Emergency and I couldn't be arsed to reset all the App and Device menu settings...

... I'd physically just turn off the Powerwall during the Car Charging period. As it's the daytime, it didn't matter.

Can't pull power from it if it's turned off...
 
How long do you have to wait for a tesla installer to make contact after going through the website? Thought I'd kick that off for a quote while I wait for so.energy to pull their finger out.

It took a week between me filling in the form on the Tesla site and someone contacting me.

I've already started talking direct to people locally however, though that isn't progressing very quickly either. One of the people I contacted directly was the one that got the nod from Tesla.
 
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I am going to Solar Panel, and I have done my homework and unfortunately, I cannot consider anymore the Tesla battery because they are too expensive, and I cannot see how I will recover the money in time. Then I have found a good compromise with In2gr8ted company (www.in2gr8tedsolutions.co.uk) with some Good Material. I did have the choice of PV/Inverter/Battery I could use, and the Guy (Paul G) was very useful to give me all the informations I need and answering all my questions. We have exchange more than 10 emails and spend 2 to 3 hours (4 phone call) then I can get anything I need to understand what I need. I have decided to go for:
  • 12 Solar Panels: Tiger Mono-Facial N-Type All black 400-watt form JINKO Solar (400Wh - Power output warranty Year 30 year at 87.4% - Maximum power efficiency at 20.96% - Lowest Temperature Coefficient (PMAX) at -0.34%/⁰C) - 25 years product warranty
  • 1 Hybrid Inverter 5Kw: GivEnergy GIV-HY5.0 – 10 years product warranty – IP65 – Compatible with Octopus - Flexible rate tariff compatible - Dual MPPT - WIFI or/and 3G connectivity - (https://givenergy.co.uk/pdf/Version-2021/hybridinverter.pdf)
  • 1 Battery 8.6Kwh: GiveEnergy Hybrid - 10 years unlimited cycle guarantee - 100% depth of discharge (https://givenergy.co.uk/pdf/Version-2021/Bat8.2.pdf)
There is an interesting YouTube video about the GivEnergy system:
it is not new, but it is quite self-explanatory, and the guy is pretty cool 😉 (from Yorkshire)

The overall bill will be £9960, and I will ROI (return on investment in year 9). I am only living in the country for 6 months, but I was living 100% in UK my model will give years 6 instead of year 9

I have compare the price between ShellEnergy, OctopusGo and EDFGoELectric and The overall cost is pretty much similar between EDF and Octopus Go (the night cost is lower, but the Daily rate and the day cost are higher)
The difference as far I know is OctopusGo give me a fixe price for 1 year and for EDF no fixed price is mentioned on the quote. So not sure what will the tariff in few month time.

I think I am going to GO with OctopusGo

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