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How to charge your electric car with solar panels
Here's how solar works with EV charging, how many panels you need, and rough costs.
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At a glance
💷 Solar charging is £700 cheaper per year than public charging, on average
A solar-compatible electric car charger costs the same as a standard model – around £1,000 – and by combining it with solar panels, you can save around £700 per year compared to charging in public.
With this setup, you can typically power your car with 82% solar electricity throughout the year – and you can use the excess solar energy in your home.
And if you're on the fence about getting an electric vehicle, let alone a charger, you should know that it costs around £1,100 less every year to charge an electric car than a petrol model.
🔌 An EV charger typically costs £1,000
An electric vehicle charger costs £1,000, on average.
There are some top-tier models available for around £700, while you can also purchase chargers with additional features for anywhere from £1,200 to £3,000.
🌍 You can save 248 kg of CO2 per year
You can save 248 kg of CO2 per year by charging your car with solar electricity, in addition to the 1.5 tonnes you save every year by driving an EV instead of a petrol car.
Electricity from the national grid is considerably greener than it used to be, but it still emits 149g of CO2 per kWh.
The average EV owner requires 2,029kWh to power their annual driving distance of 6,600 miles, around 82% of which can typically be supplied with solar panels, according to our calculations.
Due to seasonal variations in amounts of daylight, the remaining 18% will typically be supplied by the grid. You can power your car with 100% solar electricity, but it’ll require an inefficient, oversized system.
🔋 A battery helps enormously with solar EV charging
A storage battery helps with EV charging by storing solar electricity so you can use it to charge your car after the sun goes down.
Without a storage battery, your solar panels can only charge your EV when they’re producing electricity, during the day.
And if your solar panel system produces a lower output than your EV charger – for instance, if it’s a 4kWp (kilowatt-peak) array powering a 7kW charger – you’ll still use some grid electricity alongside your solar energy.
And you won’t be able to use any solar electricity in this process if your car’s not usually home when the sun’s up.
🌞 You'll generally need a 5.9kWp solar panel system to power your home and EV
The average three-bedroom household that’s looking to power its appliances and charge an EV will need a 5.9kWp solar panel system, which is 15 solar panels at 400W each.
However, you can only put this plan into effect if your car is home during all daylight hours, or if you have a storage battery.
Since the typical three-bedroom home requires a 3.5kWp solar panel system, you should view 2.4kWp as the amount you need to add on to the size of solar panel system you’d usually get for your property, if you didn’t have an EV.
Solar panels generate free, clean electricity – so naturally, you’ll want to use it to power everything in your life.
Charging your electric vehicle with solar electricity can save you hundreds of pounds, slash your carbon footprint, and reduce your dependence on public charging stations and the grid.
In this guide, we’ll explain how using solar panels to charge an electric car works, what the best setup is, how much it costs upfront, and how much you can save.
To find out how much a solar & battery system could save you in the long run, answer a few quick questions below and we'll generate an estimate.
Can you use solar panels to charge an electric car?
You can absolutely use solar panels to charge an electric car.
Your solar panels will come with an inverter that converts the DC (Direct Current) electricity that comes from the sun to AC (Alternating Current) electricity, which you can use in your home and to charge your car.
So once you’ve bought your solar panel system and EV, you can technically plug your car into a wall socket – but that would be slow, inefficient, and potentially hazardous.
Instead, you should get an EV charger, which will use solar electricity to replenish your car’s battery as it’s being generated by your panels.
Unless you have a particularly large solar panel system, your charger will usually combine the solar energy you generate with electricity from the grid, to reach its standard output level.
Alternatively, you could buy a solar-compatible charger, which allows you to choose when you charge your car, and use exclusively solar electricity when you do so.
This works even more productively when combined with a solar battery, which enables you to store your solar energy up during the day, then charge your car at night.
Verified expertElectric cars and solar panels go together hand in hand, so it’s no surprise that an EV driver is seven times more likely to have solar panels than the national average. Driving an EV makes you greener and cuts your costs - throw in some solar and both of these things improve even further. If you’re thinking of getting one of these technologies, we thoroughly recommend the other!
Alfie Ireland
Head of Operations & Technical at Sunsave
Alfie has worked in green tech for over a decade. During his four years at OVO, he helped develop the world’s largest domestic vehicle-to-grid trial.
🤔 Thinking of going solar? Here's why a larger system makes sense ⬇️
When you’re switching to solar, it's worth getting as large a solar & battery system as you can.
A few extra solar panels won't add much to the overall cost, but in most cases they'll have a big impact on your energy bill savings.
And for the majority of homes, a larger battery will significantly increase the value you get from your solar panels.
To understand all the key reasons in detail, check out the articles below.
How does it work?
If you buy an EV charger that isn’t fully compatible with solar panels, it will still use the electricity your panels generate, either while it’s being produced or from your solar battery, if you have one.
However, you won’t be able to control what source your charger uses; it’ll simply draw electricity from wherever it can.
That means it’ll probably use some grid electricity if you charge your car during the day, to meet the peak power rating of your EV charger.
You could also buy a technologically advanced ‘solar charger,’ which allows you to charge your car with solar electricity more effectively, with more options.
These chargers usually come with a CT (Current Transformer) clamp that automatically turns the charger on when it senses your solar panels are generating electricity.
The rest of the time, your charger either won’t fill your car’s battery at all, or will do so using grid electricity – but relatively slowly.
When compared to a regular EV charger, a solar charger can significantly increase how much of your solar electricity you use to charge your car.
This will allow you to cut your electricity bills, and ensure your EV is always sufficiently charged.
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Do you need a battery as well?
A storage battery helps with EV charging by storing solar electricity so you can use it to charge your car after the sun goes down.
Without a storage battery, your solar panels can only charge your EV when they’re producing electricity, during the day.
And if your solar panel system produces a lower output than your EV charger – for instance, if it’s a 4kWp (kilowatt-peak) array powering a 7kW charger – you’ll still use some grid electricity alongside your solar energy.
And you won’t be able to use any solar electricity in this process if your car’s not usually home when the sun’s up – which is the case for at least some of the year if, for instance, you’re among the 68% of Brits who drive to work.
If you wait until the sun’s gone down, your home charger can only use grid electricity to fill up your EV – a process that typically costs around £450 per year, according to our calculations – instead of free solar electricity.
The only way to effectively use solar panels to charge an electric car that’s not home during the day is by using them alongside a storage battery.
What are the advantages of charging your EV with solar?
There are several pros – and not many cons – of charging an electric car with solar panels.
After all, once you’ve bought the system and charger, you can generate free, clean electricity to run your car.
This can save you hundreds of pounds per year, reduce your carbon footprint, and protect you against rising energy prices – plus you can use the additional electricity your panels produce to power your home.
1. Save money on charging
You’ll save around £350 per year on charging costs by getting electricity from your solar panels instead of the grid, on average.
This saving rises to £700 when you compare it to using public charging stations, which typically charge a significant premium.
And just in case you were still wondering whether you should switch to an EV, it’s around £1,100 cheaper to run a car on your own solar electricity rather than petrol.
2. Maximise your savings with smart tariffs
If you use a smart tariff like Intelligent Octopus Go, you can save as much as possible, reaching and even exceeding the figures mentioned above.
You can use the app to set how much charge you need and when you need it, and Octopus will automatically charge your car when it’s cheapest.
This may mean using the solar electricity your panels generate, or if it’s nighttime and you don’t have a battery, the charger may use grid electricity – but for just 7p per kWh (kilowatt-hour).
Some other energy suppliers offer EV tariffs with a cheap off-peak rate that means you can save by charging your car at a specific time of the day – which is much less flexible.
3. Cut your carbon footprint
With the sun powering the great majority of your driving, you’ll typically save 248kg of CO2 per year, in addition to the 1.5 tonnes you save by driving an EV instead of a petrol car.
Electricity from the national grid is much greener than it used to be, but still emits 149g of CO2 per kWh.
The average EV owner requires 2,029kWh to power their annual driving distance of 6,600 miles, around 82% of which can typically be supplied with solar panels, according to our calculations.
Due to seasonal variations in daylight hours, the remaining 18% will typically be supplied by the grid.
Your solar panels will still likely produce excess electricity during the summer and spring, which you can use at home or sell to the grid, reducing your carbon footprint even further.
4. Protect yourself against energy price rises
Solar panels enable you to cut your reliance on the electricity grid.
This softens the blow of any price cap rises, as your EV charging needs can mostly be fulfilled by your solar panels.
For example, if the price of electricity rose by 10%, this would naturally add 10% to your EV charging costs – but if you only rely on the grid for 18% of your car’s electricity every year, you’ll barely notice the difference.
As of July 2024, it’d work out to an increase of £8 per year, on average.
How many solar panels do you need to charge an electric car?
On average, you need six solar panels to charge an electric car – assuming each panel has a peak rating of 400W.
However, the average three-bedroom household that’s looking to power its appliances and charge an EV will need a 5.9kWp system, which is 14 solar panels at 400W each.
3-bedroom house (no EV) | 3-bedroom house (plus EV) | |
---|---|---|
Annual electricity consumption | 2,700kWh | 4,729kWh |
Number of solar panels (400W) | 9 | 15 |
Solar panel system size | 3.5kWp | 5.9kWp |
Battery size | 5kWh | 5kWh |
Drivers rack up 6,600 miles per year, on average, or 550 per month, and the typical EV travels 3.25 miles per kWh – meaning it requires 169.1kWh per month, or 2,029kWh per year.
To generate this much electricity in the average UK location, you’d typically need a 2.35kWp (kilowatt-peak) solar panel system – or 2.4kWp, to be safe.
However, you can only put this plan into effect if your car is home during all daylight hours, or if you have a storage battery.
You’ll also only be able to power your EV with this solar panel system, and none of the rest of your home.
You should therefore view 2.4kWp as an amount to add on to the size of solar panel system you’d usually get for your property, if you didn’t have an EV.
The average three-bedroom household requires a 3.5kWp solar panel system, which equates to nine 400W panels. If you add an EV, you’ll typically need a 5.9kWp system, which is 15 panels overall.
Verified expertIf you’re planning on switching to solar and you expect to buy an electric car at some point in the future, it’s worth getting a bigger solar system so that you’re ready for it. An electric car in the UK typically uses around 2,000kWh per year, so you’ll want to have a system that can support that (or at least contribute to it).
Alfie Ireland
Head of Operations & Technical at Sunsave
Alfie has worked in green tech for over a decade. During his four years at OVO, he helped develop the world’s largest domestic vehicle-to-grid trial.
How much does it cost to charge an electric car with solar panels?
It costs £14,500 to install a solar panel system and home charging point that can charge your electric car with solar panels.
First, you need a 5.9kWp solar panel system, which typically costs around £11,500. If you add a solar battery, allowing you to store your solar electricity and use more of it to charge your car, the price tag rises by £2,000.
You’ll also need a home charger, as you can’t efficiently use solar electricity to power your car without one. These typically cost around £1,000, for an overall cost of £14,500.
The average EV needs 2,029kWh per year, which this system will produce – and thanks to the solar battery, you’ll be able to use it whether your car is home during the day or not.
However, due to seasonal variations in the amount of light that hits your solar panels, this supply of solar electricity isn’t consistent.
You’ll therefore need to import around half of your electricity from the grid in winter, plus a small amount during autumn, according to our calculations.
The good news is you’ll typically generate more than you need in order to charge your EV in spring and summer, which you can use in your home, cutting your electricity bills further.
This means even if you already have a home charger, solar panels will still save you hundreds of pounds per year on your electricity bills.
If you don’t already own a home charger, and use public chargers to top up your car’s battery instead, this setup will typically save you £700 per year.
To find out how much a solar & battery system could save you in the long run, answer a few quick questions below and we'll generate an estimate.
When is the best time to charge an electric car with solar panels?
The best time to charge an electric car with electricity from your solar panels is around the middle of the day, when the sun is highest in the sky and your system is generating the most energy.
This is often the point when your panels are generating more electricity than you can use, so instead of sending it to the grid through one of the best export tariffs, you can use it to charge your car.
However, if you have a solar battery, you can store this electricity to use in the evening or night, meaning your car doesn’t have to be home during the day to be charged.
If you’re on a smart charging tariff like Intelligent Octopus Go and you need to top-up your car’s battery further, you can then charge your car from the national grid for just 7p per kWh, any time between 11:30pm and 5:30am.
How long does it take?
It takes around six hours to charge the average electric vehicle from 20% to 80%, using a standard 7kW charger.
It’s usually best to charge your car to no more than 80%, both to lengthen your battery’s lifespan and because it takes roughly the same amount of time to charge up to 80% as it does to charge from 80% to 100%.
You can absolutely charge your car to 100%, but it’ll degrade the battery slightly every time you do, so it’s best to only do so before a long trip. When you do so, it’ll take around 10 hours.
There’s also no harm in discharging your electric vehicle below 20% – as long as you don’t leave it that way for weeks or months – but it’s always safer to have some electricity left in your battery, just in case.
If you’re using a solar charger, it’ll automatically charge your car’s battery when your solar panels are generating electricity, and use grid electricity the rest of the time – but more slowly.
This means it could take longer to charge your car, especially during winter when your panels are less productive.
Charging in the summer vs winter
Since we have seasons in the UK, the amount of daylight hours varies across the year – which means your solar panels will generate more in some months than others.
That means you’ll need to use more grid electricity to charge your car during the winter months, when the days are shorter and the skies are cloudier.
On the flip side, your panels will usually generate more electricity than you can use in summer, which means you can massively cut your EV charging bills and sell the excess to the grid with a solar export tariff.
You can see this generation pattern in the output chart below, which is based on a four-bedroom home in Essex with a 6kWp solar panel system and 5kWh battery. The system produces almost 25kWh of electricity per day in May and July, but just 4.9kWh each day in December.
What are the best EV chargers for solar charging?
These are the best electric car chargers for solar charging, because they’re designed to be compatible with solar panel systems.
Most chargers aren’t designed in this way. They can still use the electricity your solar panels produce, but you won’t be able to choose how much solar electricity they use.
Fortunately, at this stage in their technological development, it’s relatively easy to find solar-compatible EV chargers.
Here’s a rundown of all the models you can currently use to efficiently charge your EV.
Company | Charger | Solar tracking method |
---|---|---|
Easee | Equalizer | CT clamp (included) |
EO | Mini Pro | CT clamp (optional) |
EVBox | Elvi | Energy meter (optional) |
Fronius | Wattpilot (Home & Go) | Solar inverter (included) |
Hypervolt | Home 2.0 or Home 3 Pro | CT clamp (included) |
Indra | Smart PRO | CT clamp (included) |
Marlec Engineering | Veva | CT clamp (included) |
Myenergi | Zappi v2 or v2.1 | CT clamp (included) |
Rolec | WallPod SolarCharge | CT clamp (included) |
Smappee | EV Wall Charger | CT clamp (included) |
waEV-charge | EV1, EV1i, or EV1s | CT clamp (optional) |
Wallbox | Pulsar Max or Pulsar Plus | Energy meter (optional) |
What’s the best tariff for solar EV charging?
The best tariff for solar EV charging is usually Intelligent Octopus Go.
Between 11:30pm and 5:30am each day, it offers a low import rate of 7p per kWh for both your EV and domestic electricity consumption.
You can also use it alongside the Octopus Outgoing export tariff, which offers either a generous fixed rate of 15p per kWh or a variable rate.
If you use a sizable proportion of the electricity your solar panels generate, and consume less than 5,000kWh of electricity per year – as the majority of UK households do, even with an EV – this is the tariff for you.
However, if you export an unusually large amount of your solar electricity and use more than 5,000kWh per year, you may be better off on Intelligent Octopus Flux.
This tariff allows you to export solar electricity for an above-market rate during a peak period between 4pm and 7pm.
You may also want to look into Octopus Power Pack, a pioneering vehicle-to-grid tariff that allows you to store electricity in your car’s battery, then export it to the grid when it’s most profitable to you.
It’s currently only available to households with a Wallbox Quasar charger and one of the following cars: the Nissan Leaf, Nissan e-NV200, and Mitsubishi Outlander PHEV.
Next steps
You now have all the information you need to decide whether or not you want to use solar panels to cut hundreds of pounds off your annual EV charging costs.
All that’s left is to choose a solar panel system – and ideally, a solar-compatible EV charger to go with it.
If you’re wondering how much a solar & battery system could save you, just answer a few questions below, and we’ll provide you with an estimate.
Charging an EV with solar: FAQs
Is it worth installing solar panels to charge an electric car?
It’s absolutely worth installing solar panels to charge your electric car.
If you already have an EV charger at home, solar panels can save you hundreds of pounds per year, eliminating your charging bills entirely and allowing you to use the excess solar electricity to power your household.
If you don’t have a home charger, a solar-compatible one costs the same as a standard model – around £1,000 – and by combining it with solar panels, you can save £700 per year compared to charging in public.
Related Reading
Are solar panels worth it in the UK?
By Josh JackmanWhat is the cheapest way to charge an electric car?
The cheapest way to charge your electric car is with solar panels and a home charger.
With this setup, you can typically power your EV with 82% solar electricity throughout the year – and you can use the excess solar energy in your home.
Overall, this will save you hundreds of pounds per year in domestic electricity bills and EV charging costs.
Can you charge a Tesla with solar panels?
You can definitely charge a Tesla with solar panels.
Just make sure you have a Tesla-compatible home charger, and you’re good to go.
If you also have a Tesla Powerwall battery, you can use the Charge on Solar feature, which automatically sends excess solar electricity to your Tesla as it’s being generated.
How long does it take to charge a car on solar electricity?
It typically takes eight hours to charge the average electric car up to 80% with solar electricity.
This is the same amount of time that it takes to charge a car with grid electricity, since in both cases you’ll need a domestic EV charger, which usually charges at a rate of 7kW per hour.
That means you can charge your car overnight – though this setup only works if you have a solar battery that can store the electricity that your panels produce throughout the day.
Otherwise, you’ll only be able to charge when the sun’s up, which may take longer.
What size solar panel system do I need to charge my electric car?
You'll generally need a 2.4kWp solar panel system to produce enough electricity to charge your electric car.
This should work perfectly, as long as your car is either home during all daylight hours, or you have a solar battery.
You’ll also only be able to power your EV with this solar panel system, and none of the rest of your home – so make sure you factor in your other electricity usage when you’re getting a system.
The average three-bedroom household needs a solar panel system sized around 3.5kWp, so you’ll probably want to look at a 5.9kWp system, or thereabouts.
Related Reading
How many solar panels do you need?
By Josh JackmanCan I use my EV to power my house in the UK?
You can use your electric vehicle to power your home in the UK, as long as you sign up to Octopus Power Pack.
This pioneering vehicle-to-grid tariff allows you to store electricity in your car’s battery, then export it to the grid when it’s most profitable to you.
It’s currently only available to homes with a Wallbox Quasar charger and one of the following cars: the Nissan Leaf, Nissan e-NV200, or Mitsubishi Outlander PHEV.
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Read full storyWritten byJosh Jackman
Josh has written about the rapid rise of home solar for the past five years. His data-driven work has been featured in United Nations and World Health Organisation documents, as well as publications including The Eco Experts, Financial Times, The Independent, The Telegraph, The Times, and The Sun. Josh has also been interviewed as a renewables expert on BBC One’s Rip-Off Britain, ITV1’s Tonight show, and BBC Radio 4 and 5.