Can You Charge an EV from Solar Panels?
Yes, and it is one of the most financially rewarding things you can do with a home solar system. When your solar panels generate more electricity than your home is using, that surplus can be diverted directly to your electric vehicle instead of being exported to the grid.
The process works seamlessly with a solar-integrated smart charger. The charger communicates with your inverter to detect surplus solar generation and automatically adjusts the charging rate to match. On a sunny day, your car charges for free while you are at work or home, using electricity that costs you nothing to generate.
Even on cloudy days or during winter, a solar-plus-battery system can charge your EV using stored solar energy or cheap overnight grid electricity via a smart tariff. The total annual driving cost for a typical EV owner with solar panels in Hampshire can be as low as £100-200 per year, compared to £1,500-2,000 for petrol.
A 4kW solar system in Hampshire generates enough electricity to drive approximately 10,000-12,000 miles per year in a typical EV. Most UK drivers cover 7,000-8,000 miles annually, meaning solar can comfortably cover your entire driving needs.
How Much Solar Do You Need for EV Charging?
The amount of solar capacity you need for EV charging depends on your annual mileage, your car's efficiency, and how much of the charging you want to cover with solar. Most electric vehicles consume between 3 and 4 kWh per mile driven, so covering 8,000 miles per year requires approximately 2,400-3,200 kWh of electricity.
A 4kW solar system in Hampshire generates 3,600-4,400 kWh per year, which is more than enough to cover average driving distances plus a significant portion of household electricity use. However, not all of this energy can be used for EV charging, as some will power your home during the day and some will be generated when your car is not plugged in.
For the best balance between home energy use and EV charging, we typically recommend a 5-6kW solar system with battery storage for households with an EV. The battery stores surplus solar during the day and can top up your car in the evening when you return home, even after the sun has gone down. This combination maximises the proportion of free solar miles you drive.
- Typical EV: 3-4 kWh per mile driven
- 8,000 miles per year needs approximately 2,400-3,200 kWh
- 4kW solar system: covers average EV mileage in Hampshire
- 5-6kW system recommended for home + EV combined
- Battery storage maximises solar-to-EV energy transfer
If you work from home or your car is parked at home during the day, you can charge directly from solar without needing a battery. A timed charging schedule set for 10am-3pm captures peak solar generation when your panels are producing the most electricity.
Solar EV Charger Options
There are three main categories of EV charger for solar integration, ranging from standard smart chargers to advanced bi-directional systems. The right choice depends on your budget, your solar system, and whether you want vehicle-to-home capability.
Standard 7kW smart chargers are the most common and affordable option. These are AC chargers that connect to your home electrical supply and can be configured to prioritise solar generation through smart scheduling. They work well when paired with any solar system and a separate battery.
The Fox ESS L Series is a 7.3-11kW smart charger designed specifically for integration with Fox ESS solar and battery systems. It communicates directly with the Fox inverter to optimise charging based on real-time solar generation, battery state of charge, and household consumption. This tight integration provides more seamless solar charging than a generic smart charger.
The SigEnergy DC bi-directional charger represents the pinnacle of solar EV charging technology. Available in 12.5kW and 25kW configurations, it charges your car directly with DC power from the solar and battery system, eliminating the conversion losses of AC chargers. Most significantly, it supports vehicle-to-home (V2H) functionality, allowing your car battery to power your house.
- Standard 7kW smart charger: £850-1,300 installed
- Fox ESS L Series 7.3-11kW: £800-1,200 installed
- SigEnergy 12.5kW DC bi-directional: from £2,500
- SigEnergy 25kW DC bi-directional with V2H: from £3,500
Vehicle-to-Home (V2H) Explained
Vehicle-to-home technology allows your electric vehicle to act as a massive home battery. Instead of electricity flowing only from your home to your car, V2H enables bi-directional energy flow, meaning your car can also power your house. A typical EV battery stores 40-80 kWh of energy, far more than any home battery system.
The practical applications are significant. During a power cut, your EV can keep your home running for days rather than hours. In everyday use, you can charge your car cheaply overnight on a time-of-use tariff and then use the stored energy to power your home during expensive peak evening hours, profiting from the price difference.
Currently, V2H capability in the UK is limited to specific combinations of charger and vehicle. The SigEnergy DC bi-directional charger is one of the few residential systems that supports V2H in the UK market. Compatible vehicles include most models with CCS charging ports from manufacturers that have enabled bi-directional charging in their vehicle software. The list of compatible vehicles is growing rapidly.
- Your EV becomes a 40-80 kWh home battery
- Power your home during grid outages for days
- Charge cheap overnight, discharge during peak pricing
- SigEnergy DC charger supports V2H in the UK
- Growing list of compatible EV models with CCS ports
V2H technology is still maturing in the UK market, but SigEnergy is leading the way with their integrated DC charger. If you plan to future-proof your home energy system, choosing a V2H-capable charger now ensures you are ready as more vehicles support bi-directional charging.
Cost Savings: Solar EV Charging vs Petrol
The financial case for charging an EV with solar panels is compelling and grows stronger each year as petrol prices remain volatile and electricity tariffs evolve. At current prices, the cost per mile of driving an EV on solar power is approximately 1-2p, compared to 12-16p per mile for a petrol car.
For a driver covering 8,000 miles per year, a petrol car costs approximately £1,000-1,300 in fuel annually. The same mileage in an EV charged from solar costs approximately £80-160 per year if using surplus solar and smart tariff electricity. Even charging entirely from the grid at standard rates costs around £500-650 per year, still a substantial saving.
The combined savings of solar panels reducing your electricity bill and providing free EV charging typically accelerate the payback period of the entire system. A solar-plus-battery-plus-EV-charger installation that might cost £12,000-15,000 can pay for itself within 7-9 years when the EV fuel savings are factored in, compared to 10-12 years for solar and battery alone.
- Solar EV charging: 1-2p per mile
- Grid EV charging: 6-8p per mile
- Petrol driving: 12-16p per mile
- Annual saving vs petrol: £800-1,200 per year
- System payback accelerated by 2-3 years with EV savings
Keep a log of your fuel costs before switching to an EV with solar. Many of our customers are surprised to discover their total annual savings exceed £2,000 when combining reduced electricity bills with eliminated petrol costs.
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