Circular reasoning (Rolfe's solar energy system)

[salty]

I should perhaps point out that this is my house. The roof faces just slightly east of south.

View attachment 25690

Nice Pad, Rolfe. ??

 

[bobbarley]

Thanks for the video links folks, I'll watch them later today.`

I should perhaps point out that this is my house. The roof faces just slightly east of south.

View attachment 25690

Most certainly not an EV on the drive

 

[Rolfe]

Most certainly not an EV on the drive

Nope, that's Prospero, my 2009 Golf GTi. Hit by an idiot in a BMW in December 2022, insurance decided uneconomical to repair in March 2023, so succeeded by Caliban in April 2023. That Google Streetview image is from July 2021.

Here's a picture from 2007 (I think), showing Ariel, Prospero's predecessor. Peugeot 306 GTi6.

 

[Bam Bam]

Nope, that's Prospero, my 2009 Golf GTi. Hit by an idiot in a BMW in December 2022, insurance decided uneconomical to repair in March 2023, so succeeded by Caliban in April 2023. That Google Streetview image is from July 2021.

Here's a picture from 2007 (I think), showing Ariel, Prospero's predecessor. Peugeot 306 GTi6.

View attachment 25698

Nice place - big roof space!

I think batteries will increasingly make sense as the grid gets more renewables - there will be times of plenty and times of scarcity and with a battery you can buy cheap/free leccy and sell when the price is high.

But then don't you need an inverter to go with the battery? In which case is it better to get a hybrid solar inverter? In which case you are back to solar on the circle!

My regrets with the solar after year one are:
1. Not squeezing more panels on there.
2. Not getting the Pidgeon netting. Our house is now a pigeon hotel and the neighbours are threatening to bill us for car cleaning costs. Also have had dead pigeons on our lawn, driveway and in our guttering which was gross!

 

[m4rmite]

Nice place - big roof space!

I think batteries will increasingly make sense as the grid gets more renewables - there will be times of plenty and times of scarcity and with a battery you can buy cheap/free leccy and sell when the price is high.

But then don't you need an inverter to go with the battery? In which case is it better to get a hybrid solar inverter? In which case you are back to solar on the circle!

My regrets with the solar after year one are:
1. Not squeezing more panels on there.
2. Not getting the Pidgeon netting. Our house is now a pigeon hotel and the neighbours are threatening to bill us for car cleaning costs. Also have had dead pigeons on our lawn, driveway and in our guttering which was gross!

Get a kids nerf gun.
The pigeons hate it as they don't know where the bullets are coming from( out the bedroom window)
Keeps them on their toes, and i only sniping the bird feeder?

 

[Rolfe]

My installer has included bird netting in the quote. He tells me that 18 panels is the maximum he would recommend for a system like this, maybe could go to 20 but on the whole better to stick with 18 because [technobabble].

 

[johnb80]

My installer has included bird netting in the quote. He tells me that 18 panels is the maximum he would recommend for a system like this, maybe could go to 20 but on the whole better to stick with 18 because [technobabble].

But while the scaffolding is up and the guys are on site 2 extra panels would make a difference. The panels will wired in two 'strings' of 9 or 10 in your case. The inverter will have a start voltage when it can start to generate electricity to feed your house. As daylight increases the voltage from panels increase eventually meeting that start voltage. One extra panel in each string will hit that start voltage sooner and therefore be providing your energy sooner.
If I were in your position, I would go for the extra panels unless there was a very good reason not to, it would help dramatically in wintertime.

 

[GaryMG4]

It goes like this.

1. I really should get a home charger.
2. If I get a home charger, I need a variable electricity tariff.
3. A variable electricity tariff will make my daytime usage more expensive.
4. The answer is to get a home battery and fill it with cheap electricity overnight.
5. Look at your roof, if you have a home battery it would be criminal not to install solar.
6. That will be £13,700 altogether.
7. But I could buy a hell of a lot of electricity for that. Um.
8. But I really should get a home charger.

How do you get out of this loop?

I'm in a similar quandary, although I have solar on FiT, and oil fired heating (no mains gas here). I decided that a I'd see how I got on over the winter without a 7.2kW charger, after all I have a few DC chargers 5 or so miles away and although expensive I could use them in a pinch. In the last 6 months I have used the DC chargers twice, spending a total of £22 with £10 of that on 'ooh lets try the new Sainsbury charger'.
As it stands with one car to charge using the granny isn't an issue, at no point have not been able to go where I want when I want because the car didn't have enough charge. If I take solar out of the equation, just the cost of a charger will take 2-3 years to recover using cheap electricity with my 8K a year mileage, using my solar pushes that out to around 10 years.
So for me just take item 1 out of the list and the circle is broken, but circumstances may change and if they do I will reassess.

 

[Robf]

My experience was a bit different. I am not sure that now I would bother with the panels and just go for a good capacity battery, charged via intelligent octopus (or similar) when not charging car and use battery during day outwith cheap rates. Definately would go for the 7kw car charger (that works with Octopus intelligent, but Zappi might be a bit over the top) again as its cheap and so easy to charge from home.

 

[GaryMG4]

My experience was a bit different. I am not sure that now I would bother with the panels and just go for a good capacity battery, charged via intelligent octopus (or similar) when not charging car and use battery during day outwith cheap rates. Definately would go for the 7kw car charger (that works with Octopus intelligent, but Zappi might be a bit over the top) again as its cheap and so easy to charge from home.

I think if was still doing my 100 mile round trip daily commute, it would tilt the balance in a different direction, IO go would be a no-brainer. Being retired making use of the solar is a non event and even in winter I can add a significant proportion for free. using the granny means that even when the panels are only producing 1.2kW I'm still getting half price charging whereas using a Zappi it would either stop charging or add 6kW of grid to charge my car, (although in summer the Zappi would use all of the 3.5-3.9 kW the panels can produce).
Being fortunate enough to be on FiT I get paid 20+p per kWh for producing solar even if I then use it myself, if electricity prices continue to drop I will be back in the position where the FiT payments cover my annual electricity bill.

 

[johnb80]

My experience was a bit different. I am not sure that now I would bother with the panels and just go for a good capacity battery, charged via intelligent octopus (or similar) when not charging car and use battery during day outwith cheap rates. Definately would go for the 7kw car charger (that works with Octopus intelligent, but Zappi might be a bit over the top) again as its cheap and so easy to charge from home.

100% spot on. Using a wallbox is well worth the money for the convenience alone IMHO.

I think if was still doing my 100 mile round trip daily commute, it would tilt the balance in a different direction, IO go would be a no-brainer. Being retired making use of the solar is a non event and even in winter I can add a significant proportion for free. using the granny means that even when the panels are only producing 1.2kW I'm still getting half price charging whereas using a Zappi it would either stop charging or add 6kW of grid to charge my car,

No it wouldnt, it would reduced charge level down and follow the export amount. I think the minimum on AC charging is 1.4kW but it will modulate all the way up to 7.2 kW as the panels produce etc.

(although in summer the Zappi would use all of the 3.5-3.9 kW the panels can produce).

Only if thats what you were exporting, it's usually configured to keep export to zero dumping excess energy into the car.

Being fortunate enough to be on FiT I get paid 20+p per kWh for producing solar even if I then use it myself, if electricity prices continue to drop I will be back in the position where the FiT payments cover my annual electricity bill.

IOG is a no brainer, you can be exporting all what you generate at 15p and you can charge your EV at 7.5p, theres the no brainer!!

 

[GaryMG4]

No it wouldnt, it would reduced charge level down and follow the export amount. I think the minimum on AC charging is 1.4kW but it will modulate all the way up to 7.2 kW as the panels produce etc.


Only if thats what you were exporting, it's usually configured to keep export to zero dumping excess energy into the car.


IOG is a no brainer, you can be exporting all what you generate at 15p and you can charge your EV at 7.5p, theres the no brainer!!

I stand corrected regarding the Zappi, although you have confirmed that the Zappi will quit below 1.4 whereas the granny will use grid to bring it up to 2.2, which I am happy to do as its still half price electricity.
Re buying at 7.5p and selling at 15p, with FiT I get paid 20+p for producing and charge my EV for free using the same solar power.

 

[Rolfe]

Why do you say the Zappi is a bit over the top?

 

[johnb80]

I stand corrected regarding the Zappi, although you have confirmed that the Zappi will quit below 1.4

Thats a limitation of the car charger standard, the pilot signal can set the demand to levels from 1.4 KW up to maximum.

whereas the granny will use grid to bring it up to 2.2, which I am happy to do as its still half price electricity.

You also have that option with Zappi and you use it in many ways eg top up the solar by 1.5 kW from the grid or add from the grid to make the total 3 kW, whatever you want really, it's a very flexible wallbox with most conditions catered for.

Re buying at 7.5p and selling at 15p, with FiT I get paid 20+p for producing and charge my EV for free using the same solar power.

Yep but you could be getting your 20p FiT payment plus 15p export and then charging via IOG at 7.5p. You would be selling your energy to the grid at 15p and buying it back later at 7.5p making 7.5p profit on every kWh used in your car and home overnight.

 

[Robf]

Why do you say the Zappi is a bit over the top?

The Zappi is a very good charger and does works very well with solar, battery etc. However it is a bit on the expensive side and you may take a bit of time to get used to the different settings. When I had solar panels and Zappi (1st release) in my previous house I eventually gave up on the solar to charge car (was not comfortable with the off / on cycling during cloudy days), and as I was on a good FIT payment exported solar and charged car at night on cheap 5p OG rate (as it was at the time).
Without solar panels and using OIG with battery, I would use the cheaper charger with simpler functionality.

 

[GaryMG4]

Thats a limitation of the car charger standard, the pilot signal can set the demand to levels from 1.4 KW up to maximum.


You also have that option with Zappi and you use it in many ways eg top up the solar by 1.5 kW from the grid or add from the grid to make the total 3 kW, whatever you want really, it's a very flexible wallbox with most conditions catered for.


Yep but you could be getting your 20p FiT payment plus 15p export and then charging via IOG at 7.5p. You would be selling your energy to the grid at 15p and buying it back later at 7.5p making 7.5p profit on every kWh used in your car and home overnight.

The Zappi sounds like a flexible device, I did see an installer was having issues with warranty claims with them where they changed installation requirements after the item was installed and refused the claim as it didn't meet their 'current' requirements.
I think to receive FiT and export payment you need to replace the generation meter with an export meter and lose the deemed usage payment part of FiT.

 

[johnb80]

The Zappi sounds like a flexible device, I did see an installer was having issues with warranty claims with them where they changed installation requirements after the item was installed and refused the claim as it didn't meet their 'current' requirements.

I saw the video too which in my view was click bait. I personally would have challenged MyEnergi if theyd taken that stance with me. I installed my own Zappi and they have been spot on when I had an issue with a stuck relay after about 18 months.

I think to receive FiT and export payment you need to replace the generation meter with an export meter and lose the deemed usage payment part of FiT.

Not sure on that one, for me they added a virtual meter inside the smart meter which records export and also the Octopus Mini can show it in realtime

 

[GaryMG4]

I saw the video too which in my view was click bait. I personally would have challenged MyEnergi if theyd taken that stance with me. I installed my own Zappi and they have been spot on when I had an issue with a stuck relay after about 18 months.


Not sure on that one, for me they added a virtual meter inside the smart meter which records export and also the Octopus Mini can show it in realtimeView attachment 25740

My IHD shows realtime usage so I guess the information is available in the smart meter.

 

[Bam Bam]

No it wouldnt, it would reduced charge level down and follow the export amount. I think the minimum on AC charging is 1.4kW but it will modulate all the way up to 7.2 kW as the panels produce etc.


Only if thats what you were exporting, it's usually configured to keep export to zero dumping excess energy into the car.


IOG is a no brainer, you can be exporting all what you generate at 15p and you can charge your EV at 7.5p, theres the no brainer!!

Intelligent OG is great, but the Givenergy EV charger we've got isn't yet compatible with it.

Currently Octopus Go Outgoing gives you 8p export rate, not 15p.

Otherwise you could buy electricity at 7.5p overnight and sell it during the day for 15p!

Hopefully IOG will be available for Givenergy charger by the Autumn when I'll be looking to switch over from Flux to get cheap charging.

 

[johnb80]

Currently Octopus Go Outgoing gives you 8p export rate, not 15p.

Otherwise you could buy electricity at 7.5p overnight and sell it during the day for 15p!

You think ?

So they wouldn't do this then: ?

Hopefully IOG will be available for Givenergy charger by the Autumn when I'll be looking to switch over from Flux to get cheap charging.

It seems dependent on the manufacturer releasing the API details and giving access to it.