Can You Charge an Electric Car with Solar Panels?

Options for Charging an EV at Home

There are three possible ways to charge an EV at your property:

1. Using a standard three-pin plug. This option is not recommended and takes around 12 to 15 hours, but it can be a backup in an emergency!
2. Fitting a standard home charging station, which takes roughly four to eight hours to charge an EV, depending on the battery size. The charger is connected to your home electricity supply but usually has a dedicated charging unit installed on the wall.
3. Installing an EV charging unit as above with a converter that uses solar energy collected from panels on your roof and a solar storage battery to run your EV charger and other appliances.

Public chargers are also available but cost more than charging at home. Rapid chargers, commonly found at motorway service stations, are useful for long journeys. Still, continued use can degrade your battery and cause your EV's battery capacity to fall faster than it should.

How to Charge an EV With Solar Power

Solar PV systems use a grid of solar cells erected on your roof, which absorb solar energy and convert it into electricity suitable for use on a standard home circuit. You will need a compatible EV charger to link with your solar circuit and can charge the car for free!

If you are at home during daylight hours, you can charge an EV directly from a solar panel. However, most homeowners prefer to charge an EV overnight since it can take some time.

A battery storage system preserves solar energy for later use – to power appliances or use for charging. One of the positive aspects of a modern solar panel system is that it can generate power through UV light even in poor weather conditions.

An inverter changes the electrical current from DC to AC, making it safe and compatible with your home electrical system. Any surplus energy is kept in the battery for on-demand use whenever you need it.

If you are registered with the Smart Export Tariff, you can sell extra energy back to the national grid and earn a small income stream to supplement the savings you are already making by reducing reliance on electricity.

Possible Savings Using Solar Energy to Charge Your EV

Switching from a diesel or petrol car can save a considerable amount on fuel costs. However, depending on how frequently you need to charge your EV, it may mean a potentially higher electricity bill.

Electricity costs have risen, from a previous average of £0.28 per kWh to £0.34 per kWh under the Energy Price Guarantee – but regardless of your tariff, charging an EV has become more costly, albeit less expensive than refuelling.

One option is to look at tariffs specifically designed for EV drivers, which charge rates as low as 4.5 pence per kWh, although you need to recharge overnight, with the lowest rates available from around 11 pm.

Another cheaper alternative is to use solar power, particularly if you already have solar panels installed and need an adaptor to recharge your EV directly from your solar battery.

As a rough idea, the table below shows the battery size in kWh of some popular EV models and what it might cost per charge to power your battery using electricity at standard and low-tariff rates. The amount you stand to save is either of these costs multiplied by the number of times you expect to charge your EV per week or month.

Advantages of Recharging an EV With Solar Power

The cost saving is the primary advantage of using a solar system to recharge your EV. If you have a set of solar panels already installed and have a solar battery, it is as simple as fitting a charging station and connecting this to the system.

Alternatively, you can install a new EV charging dock and have a solar power system installed at the same time; the initial outlay will pay for itself once you switch from electricity usage to solar power.

Homeowners interested in free solar power and sustainable living considering a solar system can combine both projects to minimise their carbon footprint, reduce or eliminate electricity bills, and ensure they can charge their EV for free at any time of day or night.

There are several other benefits to recharging an EV with solar panels:

• Installing a solar battery means you store surplus electricity for any time you need it, for example, powering appliances and lights in the evenings. Surpluses can be sold back to the national grid in return for payment, so if you collect more than you use, your solar panels could return an income stream.
• Green footprint: many people opt for an EV because they are cleaner, environmentally friendly and have a significantly smaller carbon footprint than any petrol or diesel car. Using solar to charge your EV reduces your carbon emissions even further.
• Solar charging is available as and when you need it. You won’t need to wait until late in the evening to take advantage of lower electricity tariffs and can charge your car at your convenience.
• EV chargers are flexible, so you can connect your charging station to both your solar system and the grid, with the option of using mains electricity if your solar battery ever happens to be empty.

Having a solar EV charger installed at your home may also mean that you increase the value of your property, with the change to car sales rules coming in 2030. A free solar electricity system and free EV charging are big selling points.

Drawbacks to Solar Charging for EVs

While there are considerable benefits to charging an EV with solar power, it’s important to understand the negatives before you make any decisions.

There is an initial cost, and fitting a large solar panel grid, inverter and battery can be expensive – but you may be able to take advantage of government grant schemes currently focused on reducing the cost of installing charging points and renewable energy equipment.

Another is that solar power may be less reliable. If you use a significant amount of power or have a larger home, you may still need to use national grid electricity if your solar battery cannot store the full amount of energy required for other purposes.