I recently took delivery on a ID3 Pro Performance 77kw after waiting 18 months, its surpassed my expectations.
My house has very decent south facing roof and I'm considering installing solar panels to charge the vehicle, particularly as my car spends at least 5 days a week parked on the drive. I'd be interested in hearing anyones experiences of charging their vehicle withsolar, ie how much power you can collect in summer / winter in the UK.
Also be interested if anyone has experience of bi-directional charging. I'm thinking in summer my battery may get fully charged and FIT's these days tend to be poor. Is this possible with the ID3, does it require much additional inverter infrastructure?
Solar charging the ID3 / Bi-directional charging
I wasn’t aware the ID3 supported bi directional? Also bi directional chargers are really expensive right now and I am not sure of availability as you may need a VW specific one. Wallbox make and sell one in the USA.
This technology is still in its infancy and so you can't really buy something that works yet. The main consumer deployment I know about is Ford in the US with the F-150 Lightning and the Charge Station Pro (https://www.ford.com/trucks/f150/f150-l ... ation-pro/) which is designed to act as a home backup. The technology isn't fully there though, because it's still limited to the case where your home is powered by the car/truck OR the grid (enforced by a grid connection cut-out switch connected to the charger).
There are a few distinct issues involved. Some of them are shared with PV installs. If you go and get a solar panel and battery set up for your house, it won't make a difference when you have a power cut. That's because the systems aren't allowed to send power back through your electricity meter and onto the shared electricity distribution network unless that network is currently active and able to supply power the other way. The reasoning is that you shouldn't be in control of whether the cables outside of your house are live or not. Therefore, the only way to power things from your PV/battery system during an outage is to disconnect them from the grid entirely. It's common for PV setups to provide an internal-only mains supply that won't be shut off in the event of a power cut, and you can use this to power specific loads (e.g. fridges and freezers). The alternative is to fit a cut-out switch between your consumer unit and your electricity meter so that the entire house can be disconnected and so you don't need to change how things are wired internally.
In a PV install, unless you're doing it all off-grid low voltage, you'll have an inverter to turn the PV DC into AC mains power. These inverters need to be certified to be allowed to be connected to the mains grid, as they could otherwise cause unexpected electrical problems for other customers. Adding a battery onto a PV system is normally cheapest if it can reuse this inverter, so that it can take DC from the panels when there's sun and DC from the battery when there's not enough sun. You normally also get a transformer to turn the AC mains power into DC for the battery, so that you can charge it up from the mains when that makes sense (e.g. on Economy 7).
EVs have a battery that needs DC. To make home and public charging as easy as possible, they come with an onboard AC-DC transformer which can take raw mains power from the grid and use it to charge up the battery. The car gets 230V at 32A for a normal domestic 7kW charger. All the EVSE actually does is act as a smart switch to turn on and off the 230V mains supply to the car, and to communicate with the car about how many amps it's allowed to pull from that mains connection. All the other smart features like integration with PV are just about telling the car exactly how many amps to pull at that moment in time.
Public fast chargers are based on DC. The mains grid is turned to DC power in big AC-DC transformers normally sitting near to the fast charging unit. CHAdeMO (older Japanese models) and CCS (everything else) work in different ways but the basic principle is the same - that the DC pins are connected pretty much directly to the battery terminals and the car's onboard computers talk to the fast charger's onboard computers about exact voltage and current requirements.
Cars have inverters on board. That's how the DC power from the battery ends up as the three-phase AC needed to run the motor. However, they can't easily reverse the onboard charger and turn DC battery power back into AC power coming back over the AC pins in the charging connector. Some car models can do it, but only as Vehicle-to-Load. This is equivalent to the power outage supply capabilities of home PV systems. The inverter on board the car is not certified to be connected to the mains grid, because of certification reasons and because an isolator would still be required to separate your home electrics from the public network. It's fine to plug some specific thing into the car, like how Hyundai/Kia offer the adapter that gives you a 13 amp mains socket.
The F-150 Charge Station Pro is actually a home DC charger. That means it's a much more expensive bit of kit than a normal EVSE, because it actually needs to have the electrics to turn mains AC into DC for the car. Inside the box they've also added an inverter, so that the battery DC can be turned back into mains power for the house. To work during an outage, that isolator switch also needs to be installed and the charger and isolator switch talk to each other. I think the slightly odd split-phase power they have in the US is the reason it needs to be a DC home charger and inverter setup. In principle, the F-150 should be able to have an onboard inverter and supply 80A at 240V back to the house, where a simpler EVSE could still talk to the isolator switch and make it all work. But, in the US, single family homes are provided with two 120V AC mains connections at opposite phases; anything needing 120V gets connected from one of them to neutral and anything needing 240V like a stove, AC, water heater or EVSE is connected across both of them. The J1772 and Tesla AC connectors only have a single live, so even though they can provide 240V back, it's not trivial to turn that back into the 120V needed for most home appliances.
In the UK, the only vehicle-to-grid trial used a CHAdeMO DC home charger and inverter. That meant it was only available to Nissan Leaf/NV200 drivers. The inverter in this charger was grid certified as part of the trial, as the whole purpose of it was to feed power back to the public grid. It would still need to turn off during a power outage, unless an isolator was fitted, but being grid-certified means in non-blackout situations it's still fine for it to feed power back to things in the house like any normal PV/battery setup. These chargers will always be much more expensive than a simple EVSE, because they are doing much more than just being a switch.
The real perfect end state is that cars are fitted with AC inverters on board which are grid-certified, so they can supply power back to your home without needing an expensive home DC charger/inverter combo. This will cover the case when there aren't power outages. If power outages are really a problem, then fitting an isolator and having it talk to the EVSE is the simplest solution. We're relatively lucky in the UK that our power is relatively reliable, as we don't have as many extremes of weather/natural disasters and our last mile supply infrastructure is largely underground rather than elevated. It's unlikely most people would ever justify fitting the isolator.
The main challenge remaining in a power outage is that either a home PV/battery system or an EV providing V2H won't be able to provide as much current as the electrical system might have been designed for. With battery power being precious, you probably don't want to waste it on things you don't need either. A house can have a 100A supply, meaning that it's fine to run an electric stove at the same time as someone has an electric power shower, but you'd only be able to do one of those two things at the same time if you're running off battery power.
There are a few distinct issues involved. Some of them are shared with PV installs. If you go and get a solar panel and battery set up for your house, it won't make a difference when you have a power cut. That's because the systems aren't allowed to send power back through your electricity meter and onto the shared electricity distribution network unless that network is currently active and able to supply power the other way. The reasoning is that you shouldn't be in control of whether the cables outside of your house are live or not. Therefore, the only way to power things from your PV/battery system during an outage is to disconnect them from the grid entirely. It's common for PV setups to provide an internal-only mains supply that won't be shut off in the event of a power cut, and you can use this to power specific loads (e.g. fridges and freezers). The alternative is to fit a cut-out switch between your consumer unit and your electricity meter so that the entire house can be disconnected and so you don't need to change how things are wired internally.
In a PV install, unless you're doing it all off-grid low voltage, you'll have an inverter to turn the PV DC into AC mains power. These inverters need to be certified to be allowed to be connected to the mains grid, as they could otherwise cause unexpected electrical problems for other customers. Adding a battery onto a PV system is normally cheapest if it can reuse this inverter, so that it can take DC from the panels when there's sun and DC from the battery when there's not enough sun. You normally also get a transformer to turn the AC mains power into DC for the battery, so that you can charge it up from the mains when that makes sense (e.g. on Economy 7).
EVs have a battery that needs DC. To make home and public charging as easy as possible, they come with an onboard AC-DC transformer which can take raw mains power from the grid and use it to charge up the battery. The car gets 230V at 32A for a normal domestic 7kW charger. All the EVSE actually does is act as a smart switch to turn on and off the 230V mains supply to the car, and to communicate with the car about how many amps it's allowed to pull from that mains connection. All the other smart features like integration with PV are just about telling the car exactly how many amps to pull at that moment in time.
Public fast chargers are based on DC. The mains grid is turned to DC power in big AC-DC transformers normally sitting near to the fast charging unit. CHAdeMO (older Japanese models) and CCS (everything else) work in different ways but the basic principle is the same - that the DC pins are connected pretty much directly to the battery terminals and the car's onboard computers talk to the fast charger's onboard computers about exact voltage and current requirements.
Cars have inverters on board. That's how the DC power from the battery ends up as the three-phase AC needed to run the motor. However, they can't easily reverse the onboard charger and turn DC battery power back into AC power coming back over the AC pins in the charging connector. Some car models can do it, but only as Vehicle-to-Load. This is equivalent to the power outage supply capabilities of home PV systems. The inverter on board the car is not certified to be connected to the mains grid, because of certification reasons and because an isolator would still be required to separate your home electrics from the public network. It's fine to plug some specific thing into the car, like how Hyundai/Kia offer the adapter that gives you a 13 amp mains socket.
The F-150 Charge Station Pro is actually a home DC charger. That means it's a much more expensive bit of kit than a normal EVSE, because it actually needs to have the electrics to turn mains AC into DC for the car. Inside the box they've also added an inverter, so that the battery DC can be turned back into mains power for the house. To work during an outage, that isolator switch also needs to be installed and the charger and isolator switch talk to each other. I think the slightly odd split-phase power they have in the US is the reason it needs to be a DC home charger and inverter setup. In principle, the F-150 should be able to have an onboard inverter and supply 80A at 240V back to the house, where a simpler EVSE could still talk to the isolator switch and make it all work. But, in the US, single family homes are provided with two 120V AC mains connections at opposite phases; anything needing 120V gets connected from one of them to neutral and anything needing 240V like a stove, AC, water heater or EVSE is connected across both of them. The J1772 and Tesla AC connectors only have a single live, so even though they can provide 240V back, it's not trivial to turn that back into the 120V needed for most home appliances.
In the UK, the only vehicle-to-grid trial used a CHAdeMO DC home charger and inverter. That meant it was only available to Nissan Leaf/NV200 drivers. The inverter in this charger was grid certified as part of the trial, as the whole purpose of it was to feed power back to the public grid. It would still need to turn off during a power outage, unless an isolator was fitted, but being grid-certified means in non-blackout situations it's still fine for it to feed power back to things in the house like any normal PV/battery setup. These chargers will always be much more expensive than a simple EVSE, because they are doing much more than just being a switch.
The real perfect end state is that cars are fitted with AC inverters on board which are grid-certified, so they can supply power back to your home without needing an expensive home DC charger/inverter combo. This will cover the case when there aren't power outages. If power outages are really a problem, then fitting an isolator and having it talk to the EVSE is the simplest solution. We're relatively lucky in the UK that our power is relatively reliable, as we don't have as many extremes of weather/natural disasters and our last mile supply infrastructure is largely underground rather than elevated. It's unlikely most people would ever justify fitting the isolator.
The main challenge remaining in a power outage is that either a home PV/battery system or an EV providing V2H won't be able to provide as much current as the electrical system might have been designed for. With battery power being precious, you probably don't want to waste it on things you don't need either. A house can have a 100A supply, meaning that it's fine to run an electric stove at the same time as someone has an electric power shower, but you'd only be able to do one of those two things at the same time if you're running off battery power.
ID.3 Family Pro - 145PS, 58kWh
Kings Red - Assistance Pack Plus - Heat pump
Ordered 8th December 2021
Build week 49/2022
Delivered to dealer 11/01/2023
Collection date 17/01/2023
Front safety camera stopped working 1 hour, 30 miles into ownership.
Kings Red - Assistance Pack Plus - Heat pump
Ordered 8th December 2021
Build week 49/2022
Delivered to dealer 11/01/2023
Collection date 17/01/2023
Front safety camera stopped working 1 hour, 30 miles into ownership.
We have a 4KW solar panel array on a south facing roof, it produces about 3.7kWh a year of which the house uses about half and the rest is exported, or more recently is put into a house battery system. I would definitley consider getting solar panels and possibly a battery to reduce your house bills, but don't expect too much in terms of charging the car.
We have a relatively small set of solar panels (4kw was the max under old FIT rules), but my experience of car charging as follows:
- if you have a charger that can do solar dvert you can set it to only charge when excess generation is greater than 1.4kW (the min the car needs to charge). This means that when excess drops below 1.4kW (e.g. you've put the kettle on) charging stops which makes charging very slow and stop/ start can result in the car giving up and I have to plug in again. If you have a larger array this would of course be less of a problem, but a cloud passing over will result in the same stop start
- the FIT scheme has been closed for some years, you can now only get SEG payments of about 4 p/kWh for energy you actually export. Given you can still charge for 7.5p/kWh overnight on say Intelligent Octopus, you are only saving about 3p/kWh if you charge the car instead of export the power
- its all a bit of a faff to plug in, change the charger and Octopus settings and then check 2 hours later and see car has only charged 2 kWh!
As a result, I rarely bother to try and set up to charge the car, unless going to be a day of no cloud and bright sunshine (so about 10 days a year). If you have a space for 6- 8 kWh array then may be more useable to charge the car
I can't comment on availability of bi-directional charging, I know my smaller life battery will never be bi-directional, but think I would be using it to charge up with cheap power overnight to run the house duirng the day
We have a relatively small set of solar panels (4kw was the max under old FIT rules), but my experience of car charging as follows:
- if you have a charger that can do solar dvert you can set it to only charge when excess generation is greater than 1.4kW (the min the car needs to charge). This means that when excess drops below 1.4kW (e.g. you've put the kettle on) charging stops which makes charging very slow and stop/ start can result in the car giving up and I have to plug in again. If you have a larger array this would of course be less of a problem, but a cloud passing over will result in the same stop start
- the FIT scheme has been closed for some years, you can now only get SEG payments of about 4 p/kWh for energy you actually export. Given you can still charge for 7.5p/kWh overnight on say Intelligent Octopus, you are only saving about 3p/kWh if you charge the car instead of export the power
- its all a bit of a faff to plug in, change the charger and Octopus settings and then check 2 hours later and see car has only charged 2 kWh!
As a result, I rarely bother to try and set up to charge the car, unless going to be a day of no cloud and bright sunshine (so about 10 days a year). If you have a space for 6- 8 kWh array then may be more useable to charge the car
I can't comment on availability of bi-directional charging, I know my smaller life battery will never be bi-directional, but think I would be using it to charge up with cheap power overnight to run the house duirng the day
Life Pro Performance/Assistance Pack/Scale Silver/ East Derry Wheels
-
CmdrKrunchy
- Posts: 12
- Joined: Fri Nov 25, 2022 1:32 pm
To add my tuppence...
So, we have an approximately 4.2 kW solar array linked to a 3.6 kW inverter. This means it is classed as Microgeneration so the paperwork and dealing with the DNO is more straightforward/cheaper for the installer. Also, oversizing the array to the inverter seems to be a pretty common thing to make more efficient use of the inverter (there is a good explanation of oversizing here: https://www.solaredge.com/uk/solaredge-blog/oversizing )
Attached to that we have two MyEnergi products – an Eddi hot water diverter and a Zappi car charger. The idea being that when there is a small amount of excess, we fill the hot water tank, when there is a larger excess, we charge the car. Anything to reduce the amount of export.
Also, with the Zappi, we can set a percentage of electricity to import when charging on surplus solar. The IEC 61851 standard for electric vehicle chargers dictates a minimum charge current of 6 Amps i.e. 1.4kW. With the Eco+ percentage setting, the Zappi will take a set amount from the grid to allow charging to continue instead of exporting the surplus solar electricity e.g. if we have 1kW of excess solar, the car will still charge with 400W coming from the grid.
Our use case for the car and the solar system is to try and charge off surplus solar as much as possible, the ID.3 will generally be averaging around 40/50 miles per day, plus longer journeys every now and again, so in the summer months we are hoping solar should cover a lot of our mileage, with the odd nighttime charge when necessary.
We are trying to get a proper smart meter installed to allow a cheap night tariff – the previous 'smart' meter was installed when the mobile signal at our house was non-existent, thus it was never commissioned properly.
We haven't had the car long, but so far the setup has been working well. Now if we could only get some better weather!
Overall, I would really recommend solar, just as long as you have somewhere to put it that isn't the grid and preferably more than one place - EV, batteries, hot water tank, even just moving your clothes washing or dishwasher to sunnier hours, anything to reduce the amount you take from the grid and export to the grid.
PS as others have said, V2G still isn't really a thing yet and all the VAG MEB platform cars aren't capable of it.
PPS for blackouts, there are battery/inverter systems on the market with what is known as Island Mode to cover that use case.
So, we have an approximately 4.2 kW solar array linked to a 3.6 kW inverter. This means it is classed as Microgeneration so the paperwork and dealing with the DNO is more straightforward/cheaper for the installer. Also, oversizing the array to the inverter seems to be a pretty common thing to make more efficient use of the inverter (there is a good explanation of oversizing here: https://www.solaredge.com/uk/solaredge-blog/oversizing )
Attached to that we have two MyEnergi products – an Eddi hot water diverter and a Zappi car charger. The idea being that when there is a small amount of excess, we fill the hot water tank, when there is a larger excess, we charge the car. Anything to reduce the amount of export.
Also, with the Zappi, we can set a percentage of electricity to import when charging on surplus solar. The IEC 61851 standard for electric vehicle chargers dictates a minimum charge current of 6 Amps i.e. 1.4kW. With the Eco+ percentage setting, the Zappi will take a set amount from the grid to allow charging to continue instead of exporting the surplus solar electricity e.g. if we have 1kW of excess solar, the car will still charge with 400W coming from the grid.
Our use case for the car and the solar system is to try and charge off surplus solar as much as possible, the ID.3 will generally be averaging around 40/50 miles per day, plus longer journeys every now and again, so in the summer months we are hoping solar should cover a lot of our mileage, with the odd nighttime charge when necessary.
We are trying to get a proper smart meter installed to allow a cheap night tariff – the previous 'smart' meter was installed when the mobile signal at our house was non-existent, thus it was never commissioned properly.
We haven't had the car long, but so far the setup has been working well. Now if we could only get some better weather!
Overall, I would really recommend solar, just as long as you have somewhere to put it that isn't the grid and preferably more than one place - EV, batteries, hot water tank, even just moving your clothes washing or dishwasher to sunnier hours, anything to reduce the amount you take from the grid and export to the grid.
PS as others have said, V2G still isn't really a thing yet and all the VAG MEB platform cars aren't capable of it.
PPS for blackouts, there are battery/inverter systems on the market with what is known as Island Mode to cover that use case.
ID.3 Kings Red, 58kWh Family Pro Performance, Steelies, Heat Pump
Order submitted Dec 21 (Tusker Salary Sacrifice), confirmed Jan 22
Delivery date Sept 22, then Oct 22, then Nov 22, then Feb 23, then March 23, then mid April 23.
Delivered late April 2023
Order submitted Dec 21 (Tusker Salary Sacrifice), confirmed Jan 22
Delivery date Sept 22, then Oct 22, then Nov 22, then Feb 23, then March 23, then mid April 23.
Delivered late April 2023
Thanks, some interesting feedback which is educating me fast on the subject. The bi-directional things seems a few years off so will discount that idea for now. I currently pay 25p per unit off peak for a truly green tariff to charge overnight, so I see the potential saving a lot more than current SEG payment which seem very low. I hope this will change in future
I wasn’t aware there was a minimum 1.4kw generation to charge a vehicle, so how big does a system have to be to generate 5-6 hours of vehicle charge a day for 6 months a year, I’m assuming the winter half of the year won’t be much use. I have quite a large south facing roof so an oversized system does seem a possible option, ie 8kw / 40sq/m. What does an 8kw system with 4kw inverter cost?
I wasn’t aware there was a minimum 1.4kw generation to charge a vehicle, so how big does a system have to be to generate 5-6 hours of vehicle charge a day for 6 months a year, I’m assuming the winter half of the year won’t be much use. I have quite a large south facing roof so an oversized system does seem a possible option, ie 8kw / 40sq/m. What does an 8kw system with 4kw inverter cost?
4KW solar- fit south facing lowish miles- at home 5 days a week.
put the charge rate to low and plug it in at the hint of sunshine. Get 50 - 75% of the electrons free (I know thats not how it works really). paying standard electricity rates. The increased cost of daytime units greatly exceeds the reduced nighttime ones even if I completely charged at night. Reluctant to go onto the smart tariffs as at present my FIT assumes a 50% export when I think in reality it is lower. Divert remaining electricity to heat water
put the charge rate to low and plug it in at the hint of sunshine. Get 50 - 75% of the electrons free (I know thats not how it works really). paying standard electricity rates. The increased cost of daytime units greatly exceeds the reduced nighttime ones even if I completely charged at night. Reluctant to go onto the smart tariffs as at present my FIT assumes a 50% export when I think in reality it is lower. Divert remaining electricity to heat water
Here we have 6.4kw of panels (south east roof) and 10kw battery, cost around £14 k to install (March 23). Also Hypervolt charger which is supposed to charge just from solar when there is enough. I still need to get the car to know if that bit works!
We're currently on Octopus Flux so 32.4p through the day, but a decent 21p for export. Overnight is 19.4p from 2am to 5am which isn't as good as Go, but Go is only compatible with the 4p for export tariff. Flux has a peak rate from 4pm to 7pm of 45.3p, but this is when the battery works its magic.
So far this month (May) we've used 6.68kWh from the grid and exported 103kWh. For April we used 25.4kWh and exported 295.3kWh. So spring and summer will be great, but Winter will be pricier.
We tend to stick the washing machine and dryer on when the sun is out
We're currently on Octopus Flux so 32.4p through the day, but a decent 21p for export. Overnight is 19.4p from 2am to 5am which isn't as good as Go, but Go is only compatible with the 4p for export tariff. Flux has a peak rate from 4pm to 7pm of 45.3p, but this is when the battery works its magic.
So far this month (May) we've used 6.68kWh from the grid and exported 103kWh. For April we used 25.4kWh and exported 295.3kWh. So spring and summer will be great, but Winter will be pricier.
We tend to stick the washing machine and dryer on when the sun is out
—
ID3 Max Moonstone & Bike rack - Order #31554***
Week 45 22 est. Then 2023 wk 17
and then 2023 wk 14 
now (may 23) it's here! 
Hypervolt & 6.4k solar with 10k battery
ID3 Max Moonstone & Bike rack - Order #31554***
Week 45 22 est. Then 2023 wk 17
and then 2023 wk 14 now (may 23) it's here! 
Hypervolt & 6.4k solar with 10k battery
