Why solar panels + EV charging is the ultimate combination
If you drive an electric vehicle and own your home, pairing solar panels with a home EV charger is one of the smartest financial decisions you can make. Here's why the numbers are so compelling.
The maths: solar-powered driving
| Metric | Without Solar | With Solar | Saving |
|---|---|---|---|
| EV charging cost (10,000 mi) | £800/year | £0-£200/year | £600-£800 |
| Home electricity | £900/year | £200-£400/year | £500-£700 |
| SEG export income | £0 | £100-£300/year | £100-£300 |
| Total annual savings | — | — | £1,200-£1,800 |
With a 4kW solar system (£6,000-£8,000) and a home charger (£800-£1,200), total investment is around £7,000-£9,000. At £1,500/year in savings, the combined payback period is often around 5-7 years. After that, solar generation can materially reduce both household electricity bills and EV charging costs for many years.
How it works technically
Direct solar charging (daytime)
During daylight hours, your solar panels generate electricity. A smart EV charger (like the Ohme Home Pro or Zappi) can detect when solar generation exceeds your home's demand and automatically start charging your car with the surplus. You're literally driving on sunshine.
Battery storage (evening/overnight)
Adding a home battery (£3,000-£6,000) lets you store solar energy generated during the day and charge your EV overnight. This maximises self-consumption to 70-80% and means you're barely using grid electricity at all.
Smart tariff integration
On cloudy days when solar isn't enough, a smart charger paired with an EV tariff like Octopus Go charges at 7.5p/kWh overnight — still 70% cheaper than public chargers and 60% cheaper than a standard tariff.
How many solar panels do you need to charge an EV?
| Annual Mileage | Electricity Needed | Solar System Size | Number of Panels |
|---|---|---|---|
| 5,000 miles | ~1,500 kWh | 1.5-2kW | 4-5 panels |
| 8,000 miles | ~2,400 kWh | 2.5-3kW | 7-8 panels |
| 10,000 miles | ~3,000 kWh | 3-3.5kW | 8-10 panels |
| 15,000 miles | ~4,500 kWh | 4.5-5kW | 12-14 panels |
The average UK driver does 7,400 miles per year. A modest 3kW system (8 panels) would cover this with enough surplus to offset a chunk of your home electricity too.
Grants available for the solar + EV combo
Stack these grants to minimise your upfront cost:
- EV charger grant: Up to £500 off eligible charger installation routes
- Electric car grant: Up to £3,750 off eligible new EVs
- 0% VAT on solar: Saves £1,000-£2,000 on a typical system
- ECO4: Free solar panels for eligible households on benefits
- Smart Export Guarantee: Earn 4-15p/kWh for electricity exported to the grid
Best case scenario: An ECO4-eligible household gets solar funded, qualifies for a current EV chargepoint grant, then uses a cheap off-peak tariff or solar surplus for charging. That can reduce EV running costs dramatically compared with petrol.
Best EV chargers for solar
- myenergi Zappi: Specifically designed for solar integration. Eco mode automatically uses only surplus solar power. From £850 installed.
- Ohme Home Pro: Smart tariff integration + solar-aware scheduling. From £900 installed.
- Wallbox Pulsar Plus: Works with SolarEdge and other monitoring systems. From £800 installed.
The Zappi is the standout choice for solar owners — its "Eco" mode is uniquely designed to match charging speed to real-time solar generation, ensuring maximum use of free solar energy.