Solar + Zappi + MG4 = ?

[FiferMG4]

I’ve finally been able to convince my wife that the initial outlay for a Zappi, solar PV and battery storage installation has been worth it. I showed her our solar being diverted to the car (instead of British Gas) via the Zappi app and I got a big smile and thumbs up, which coming from my wife is a big win. ?

Feels great to be charging the MG4 with solar energy. 3kWh is not too shabby for Fife.

 

[Ian Key]

My trouble is that I'm arguing with myself about solar,and a home battery or just a home battery or leave it as the technology improves. Unfortunately I'm loosing...?

 

[FiferMG4]

My trouble is that I'm arguing with myself about solar,and a home battery or just a home battery or leave it as the technology improves. Unfortunately I'm loosing...?

That’s a nice argument to have! ?The panels (Trina Vertex S) I’ve had installed are rated at 425 watts with an efficiency of 20.8%. It’s a lovely sunny day and I’m getting over 4kW, so as my 9.5Kw GivEnergy battery has already been filled to 100%, I thought, “Hold on a minute. I’ve got a massive storage battery in the form of the 64kW MG4!”, so I’ve connected it to the Zappi in its Eco++ mode which maximizes solar charging as opposed to grid charging. I would say if you didn’t have an electric car then just having a home battery and charging it on cheaper off peak electricity would be the way to go.

But having the MG4, you’ve essentially got a huge home battery on your driveway which can store plenty of excess solar. When I thought about all this a year ago, having watched so many Youtube videos on electric cars, home chargers, solar panels, inverters and batteries, I had one goal in mind, to be able to power the house and car using as little grid import as possible, thus insulating myself from volatile petrol and gas/electricity prices. I feel I’ve gone quite a long way in achieving that now.

Ofcourse, everyone’s circumstances are different, but if you’re able to Ian, I’d go for a solar and battery storage system.

 

[cbowen]

My trouble is that I'm arguing with myself about solar,and a home battery or just a home battery or leave it as the technology improves. Unfortunately I'm loosing...?

If you have Solar and Battery you get the VAT removed. If you only go with a Battery install only, you have to pay VAT. I've got a Givenergy battery and inverter which has a SoC issue which they can't seem to resolve. Been going on for 12 months and they ignored it until everyone kicked off on the community pages. Wouldn't recommend them at the moment.

I'm about to have my solar array increased from 3.2kwh to 6.7kwh in the next few weeks. Excellent return on the investment when you include all the free charging in the summer!

Also worth looking at a solar hot water diverter if you have a hot water tank. I've got a Solar iBoost as I managed to get one brand new for £100 just over a year ago. They go for about £400 now. The My energi Eddi is excellent and integrates well. They go for quite a bit now so you need to heat a lot of hot water to justify it!

 

[Ian Key]

I took early retirement a couple of years ago and spent some of my inheritance on the MG4 so now I'm veering towards leaving it for another 2.5 years until I reach 66 and can maximise my pension pots.
Hopefully the technology will have improved and be easier to integrate as I'd be looking at solar, battery and some form of heat pump as my central heating is on it's last legs.
But nothing is written in stone and I'm just starting on the whole EV solar journey.

 

[IanMK]

I’ve finally been able to convince my wife...

I've still got to have this conversation

 

[FiferMG4]

I've still got to have this conversation

Best of luck to you! ???

 

[Themist0]

With the money you are now saving, I highly recommend you buy flowers

 

[StanBowlesb]

Interesting stuff. I have 2kwp solar pv on the house at the moment. I have just accepted a quote to put an additional 8.1kwp on the garage to provide 10.1kwp. I have a zappi 2 charger and am on the Octopus Agile energy tariff. I am very happy with the Zappi 2 so far. With my three phase supply I am able to charge the MG4 at 10.4kw per hour. I have been running the spreadsheet calcs, though, over having a battery installed at the same time as the solar and really can't justify the extra expense. My calcs are below. I figure battery prices need to come down a long way yet to get a decent return. As the car is home for three or four days a week, I reckon it is better just to use the solar for the car. After all there is 61kw there to fill. Not having a battery at the same time as the solar means I do lose out on possible nil VAT and, of course, there is additional labour and inverter costs if I added batteries later. It goes against my instinct not to have a battery with the solar now but I figure I have limited funds and I will revisit the issue in ten years' time. Here's my calcs:

Extra cost of hybrid inverter + 4.56kw usable cap battery (Pylontech)	£2,310.00​
Capital cost per cycle (6,000 cycles)	£0.39​
Cost per kw (4.56kw usable per cycle)	£0.08​
Saving if displacing 29p grid electricity	£0.21​
But 15p export income foregone	£0.15​
net gain per kw	£0.06​
net gain per annum (assuming battery can be used 75% of the year)	£69.37​
ROI	3.0%​

 

[Diggsy]

I’d imagine if you were to add a solar panel to your existing installation whilst adding a battery, you might not have a VAT bill. Not sure though, as haven’t really looked into it

 

[StanBowlesb]

Diggsy - yes, I could do that if the VAT concession is still on offer if I added a battery(ies) in the future. The installation I am planning is nil vat as I am having 20 extra panels. Like the original poster (fifer), my goal is to use as little grid import as possible. Having built a passive house, I have very low home energy demand anyway. The case for the added solar panels comes from using them to charge the MG4 whenever possible. Plus the economic case for the solar panels is also greatly helped by the current fixed outgoing Octopus 15p export tariff - although that could change in the future so can't be hard-baked into the financial assumptions.

 

[FiferMG4]

Interesting stuff. I have 2kwp solar pv on the house at the moment. I have just accepted a quote to put an additional 8.1kwp on the garage to provide 10.1kwp. I have a zappi 2 charger and am on the Octopus Agile energy tariff. I am very happy with the Zappi 2 so far. With my three phase supply I am able to charge the MG4 at 10.4kw per hour. I have been running the spreadsheet calcs, though, over having a battery installed at the same time as the solar and really can't justify the extra expense. My calcs are below. I figure battery prices need to come down a long way yet to get a decent return. As the car is home for three or four days a week, I reckon it is better just to use the solar for the car. After all there is 61kw there to fill. Not having a battery at the same time as the solar means I do lose out on possible nil VAT and, of course, there is additional labour and inverter costs if I added batteries later. It goes against my instinct not to have a battery with the solar now but I figure I have limited funds and I will revisit the issue in ten years' time. Here's my calcs:

Extra cost of hybrid inverter + 4.56kw usable cap battery (Pylontech)	£2,310.00​
Capital cost per cycle (6,000 cycles)	£0.39​
Cost per kw (4.56kw usable per cycle)	£0.08​
Saving if displacing 29p grid electricity	£0.21​
But 15p export income foregone	£0.15​
net gain per kw	£0.06​
net gain per annum (assuming battery can be used 75% of the year)	£69.37​
ROI	3.0%​

That sounds like a great setup you have now, especially as you are able to charge the car at 10.4kW per hour depending on the sunshine. If you get a decent day’s weather you’d easily be able to fill up the MG4’s battery.

 

[Themist0]

I suspect that once CATL and BYD start to fully ramp up sodium ion batteries, then home storage prices will start to drop, and Tesla will again strategical drop its power wall prices… might be worth waiting another 12-18 months

 

[MG4London]

Home battery is so expensive like a Tesla powerwall.

If you have solar panels then why not use the battery in your MG4 as your powerwall?

MG4 has V2L.

I understand the issue is that when the sun is shining is not necessarily when you want to use lots of power but the car can store it for you.

 

[FiferMG4]

Home battery is so expensive like a Tesla powerwall.

If you have solar panels then why not use the battery in your MG4 as your powerwall?

MG4 has V2L.

I understand the issue is that when the sun is shining is not necessarily when you want to use lots of power but the car can store it for you.

A quick search on the internet brought up prices for the Tesla Powerwall anywhere from £7,000 to £12,000, so let’s just say it’s around ten grand. The GivEnergy 9.5kWh battery I’ve had installed was just over £3,000.

You’re right MG4London that our cars are like a giant home battery, but the problem is when solar production is at its peak during the day, I’m at work, so the home storage battery is helping to store excess solar while I’m away with the car. Don’t get me wrong, if I’m at home and the car needs charged I shall be plugging it into the Zappi. That’s a win win.

 

[tsedge]

A quick search on the internet brought up prices for the Tesla Powerwall anywhere from £7,000 to £12,000, so let’s just say it’s around ten grand. The GivEnergy 9.5kWh battery I’ve had installed was just over £3,000.

Was the installed cost £3,000? and is that with VAT and inverter separately?

 

[FiferMG4]

Was the installed cost £3,000? and is that with VAT and inverter separately?

No, that’s just the price of the battery. The installation for the battery came to £2,407. I’m not sure exactly how much the GivEnergy 3.6 inverter was as they didn’t give me the breakdown for that. Fortunately, there’s a government scheme at the moment for homeowners installing a solar pv/battery storage system to waive VAT, so if you are in a position to do it, now’s the time I’d say tsedge. Not having to pay VAT on top makes for a big saving!

 

[FiferMG4]

Despite it being very overcast and drizzling here in bonny Fife this morning, thanks to the diffuse nature of the sunlight, all fifteen panels (5 east facing, 4 south facing and 6 west facing) are coming into play, so I’m still getting a decent amount of generation.

 

[Ayoull]

Despite it being very overcast and drizzling here in bonny Fife this morning, thanks to the diffuse nature of the sunlight, all fifteen panels (5 east facing, 4 south facing and 6 west facing) are coming into play, so I’m still getting a decent amount of generation.
View attachment 17089

I know someone I work with is with octopus and they get 15p per unit exported back to the grid, they don't have an EV so no octopus go, but covers their standing charge costs.

As do think it's criminal the minimal amount they recompense people for generating at home

 

[FiferMG4]

I know someone I work with is with octopus and they get 15p per unit exported back to the grid, they don't have an EV so no octopus go, but covers their standing charge costs.

As do think it's criminal the minimal amount they recompense people for generating at home

Interesting. The system was commissioned on Thursday afternoon and it says we’ve consumed 64kWh of solar generation and exported 83kWh, so does that mean were we on Octopus we would have made £12.45p? That would certainly cover the standing charge.

Yeah, the worst is, if I import back that same energy, they’d (British Gas) charge me an arm and a leg.