A guide to solar panel EV charging

Looking to cut ties with fossil fuels further and charge your EV with even greener energy? You’re not alone - more and more people are plugging into green energy, and solar-powered EV charging is fast becoming a go-to solution. It’s clean, it’s clever, and it can save you money too. Sunshine and savings? Yes please.

In this guide, we’ll take you through how solar charging works, how many panels you might need, and why it’s a great move for both the planet and your pocket.

Let’s start with the basics. Solar panels (usually perched proudly on your roof) soak up sunlight and convert it into electricity using photovoltaic (PV) cells. That energy can then be used to power your home and charge your EV.

When your panels generate more electricity than you use (think sunny summer afternoons), you’ve got options:

• Use it immediately
• Store it in a home battery for later
• Send it back to the grid and earn a little back

By connecting your solar PV system to your EV charger, you can feed all that sunshine straight into your car - but if you’ve got a smart tariff (like Intelligent Octopus Go), it might actually be savvier to export that sunshine and charge when grid rates are low. Either way, you’re cutting carbon and driving greener energy.

Yes! With the right setup, you can fully charge your electric car using nothing but solar power.

The typical UK home solar PV system generates around 3 - 4 kilowatts peak (kWp), which equates to roughly 3,000 - 3,400 kilowatt-hours (kWh) a year. That’s enough to cover a significant chunk of your annual driving - especially if you don’t do huge daily miles.

For example, if you’ve got a 40kWh EV battery and a 4kWp solar system, you could fully charge your car in around 10 hours of decent sunshine. Naturally, output varies with the seasons (hello, British weather), so in winter months, you might need to top up from the grid now and then.

Even if you can’t rely solely on solar year-round, it’s a brilliant way to slash emissions and costs – especially through spring and summer.

It depends on a few things:

• Your EV’s battery size
• How often you drive
• Your solar panel efficiency
• The average amount of sunlight where you live

But as a rough guide? A solar system with 8 to 12 panels is enough to support regular EV charging for most drivers. The best way to get an accurate setup is to chat with a solar installer - they’ll tailor everything to your energy needs and lifestyle.

Not necessarily. Most home EV chargers can work perfectly well with solar energy - as long as your system includes an inverter.

Here’s why: Solar panels produce direct current (DC) electricity, but your home and your EV charger need alternating current (AC). That’s where the inverter steps in, flipping the current so it’s usable. Most solar installations include one as standard, but always double-check.

Want to store your solar energy and charge up overnight? You’ll need a home battery system. This stores any surplus solar power generated during the day and dishes it out when you plug in at night. Ideal if you’re not around to charge when the sun’s shining.

Charging your EV from the grid is still far greener than filling up with petrol - but charging it with sunshine? That’s next-level clean.

EVs already slash tailpipe emissions, but using grid electricity can still come with a carbon footprint (depending on how it’s generated). Solar charging ensures you’re powering your car with 100% renewable energy, directly from your rooftop.

After the upfront cost of installing solar, the energy is free. The Energy Saving Trust estimates a typical 4kW system can save UK households over £400 a year on electricity bills. Add EV charging into the mix, and the long-term savings only grow.

Modern solar panels need very little TLC. Once installed, they quietly get on with the job for 25+ years, helping you drive greener and spend less.

Solar charging isn’t perfect for everyone, and it’s worth weighing up:

• Installation costs - Solar PV systems can be a big upfront investment, although government incentives and long-term savings help balance things out.
• Space and sunlight - You’ll need enough roof space and a decent amount of sunshine to get the best from your system.
• Seasonal performance - Solar energy output dips in winter, so you may need to rely more on the grid during darker months.

That said, even if solar can’t meet all your charging needs, it can still cover a good portion - especially during those brighter British months.

Here’s where things get tactical.

Solar is a brilliant way to reduce your overall energy use – especially during the day when you’re running things like fridges, appliances or a home office. But when it comes to charging your EV, using solar might not always be the cheapest option.

Thanks to export tariffs like Outgoing Octopus, you can sell your excess solar power to the grid for around 14 - 15p/kWh. Meanwhile, with smart tariffs like Intelligent Octopus Go, you can charge your car overnight for as little as 7p/kWh. So if you use your solar to charge your car instead of exporting it, you're effectively paying double the rate you need to.

So what’s the smartest strategy?

• Use solar during the day to power home essentials you can’t shift (like cooking or the fridge).
• Charge your EV overnight using low-cost, green energy via Intelligent Octopus Go or similar smart tariffs.
• Store solar in a battery if you have one – and use that to top up during peak times.

In short; if electricity is cheaper than your export rate, it's usually better to sell your solar and buy in cheaper grid energy later. Or you could also use the solar energy stored in your battery when you need to charge your car outside of the cheapest times, keeping costs low throughout the day. It’s a win-win – you earn more from your panels and spend less on charging.

If solar panels aren’t an option, you can still charge your EV with 100% renewable electricity through a green EV tariff - like Octopus Energy’s Intelligent Octopus Go. These tariffs ensure your charging is backed by clean, green sources like wind and solar farms. So, even if your roof isn’t sun-ready, your conscience still can be.

In a word: absolutely. Solar-powered EV charging is one of the cleanest, most cost-effective ways to power your journeys. With the right setup, you can:

• Drive on 100% renewable energy
• Lower your running costs
• Reduce your carbon footprint
• Even earn a little back from surplus power

So, if you’ve got the space, the sun, and the drive (pun fully intended), it’s well worth exploring further.

Learn more about EV Charging in our EV Charging Hub.