Should You Charge Your EV from Solar?

With solar installations on the rise, many homeowners ask the same question: should I use my solar panels to charge my EV? At first glance, the answer seems obvious. Solar provides free electricity, so why not use it to power your car and enjoy zero-emission miles?

The reality is more nuanced. Thanks to modern EV tariffs and export payments, there are smarter ways to combine EV charging and solar energy that could put more money back in your pocket.

How EV Charging and Solar Interact

A typical EV requires around 2,800–3,000 kWh of electricity each year to drive 10,000 miles. A standard 6 kW solar system in the UK generates about 5,900 kWh annually. That means, in theory, your solar panels could cover most of your EV charging needs.

However, solar doesn’t always generate power when you need to charge. Daytime generation peaks when many EVs are parked at workplaces or schools. Unless you charge at home during daylight hours, you may not capture that “free” solar power.

Tariffs Make All the Difference

The decision to charge an EV from solar is heavily influenced by your electricity tariff. Smart EV tariffs, like Octopus Intelligent Go or E.ON Next Drive, let you charge overnight at very low rates (around 7p/kWh). At the same time, suppliers often pay generous export rates for solar sent back to the grid, sometimes over 15p/kWh.

This creates an interesting dynamic. Instead of charging directly from solar, many households find it more profitable to export their excess solar to the grid and then charge the EV cheaply overnight. For example:

- Charging overnight: Pay 7.5p/kWh

- Exporting solar: Earn 16.5p/kWh

- Net effect: Profit of ~9p per kWh by exporting instead of diverting into the car

This means using a smart tariff can be financially stronger than plugging in your EV during the day.

Click below to watch us run the maths live on a Tesla screen!

Is It Worth the Effort?

The good news is that setting up time-controlled charging is simple. Modern EV chargers and many EVs allow you to set charging windows. You can plug in at any time, and the system will only draw electricity during the cheap off-peak window. There’s no extra faff involved, and you always retain the option to override for an urgent top-up.

So, while charging directly from solar may save you around £185 per year, combining export payments with off-peak charging can increase this to about £222. The difference isn’t life-changing - roughly £36 a year - but it demonstrates how a smart strategy maximises savings.

What About Batteries?

Some households wonder if charging an EV from a home battery full of solar energy makes sense. In most cases, it doesn’t. Factoring in battery costs and efficiency losses, each stored unit of solar can cost 14–15p before it reaches your car. That’s more expensive than charging from an off-peak EV tariff.

The best role for a battery is covering household evening demand or maximising export value on tariffs like Octopus Flux.

Solar + EV = Energy Independence

Financial logic aside, there’s still something appealing about driving on pure sunshine. Even if the annual saving is modest, many households value the independence and sustainability of powering their car directly from their roof.

The most effective strategy is to design a system with flexibility: a solar array sized for both household and EV use, paired with a smart charger that gives you control. This way you can decide when to charge your EV from solar and when to optimise for tariffs.