How much does it cost to charge an EV with solar panels?
A sunny roof and the right charger can run your car for free from April to September; winter is a different story.
Charging an EV with solar panels costs nothing per kWh at the margin once the system is installed: a typical UK 4kW array generates about 3,000 to 3,500kWh a year (Energy Saving Trust), enough to cover most of an 8,000-mile driver's roughly 2,300kWh annual charging need between spring and autumn. You need a solar-aware charger such as the myenergi Zappi or Hypervolt Home 3 Pro, and winter charging still comes from the grid.
Can you charge an EV directly from solar panels?
Yes, and the piece of kit that makes it work is a solar-aware charger. It watches your home’s export, the power your panels are making beyond what the house is using, and feeds exactly that surplus into the car. On a bright day the car drinks sunshine that would otherwise have gone to the grid for a few pence per kWh.
The two established options are the myenergi Zappi, which built its reputation on solar diversion and integrates with the myenergi ecosystem, and the Hypervolt Home 3 Pro, which does the same job via a CT clamp.34 Any charger can use solar power indirectly (your home draws less from the grid while the sun shines), but only a solar-aware unit can charge the car only on surplus.
How much of your charging can solar cover?
The annual sums line up surprisingly well. A typical UK 3.5 to 4kW domestic system generates about 3,000 to 3,500kWh a year, per Energy Saving Trust estimates.1 An 8,000-mile-a-year driver at 3.5 miles per kWh needs about 2,286kWh a year for the car.
The catch is timing, in two senses. First, seasonality: UK solar produces the bulk of its energy from April to September, and very little in November to January, so solar can plausibly cover most of your summer charging and only a sliver of winter. Second, daily timing: the sun peaks at midday and most cars charge at night. A solar-aware charger helps if the car is home by day; if it is at the office, your options are a home battery to time-shift the power, or simply charging at weekends.
A realistic expectation for a commuter who charges at weekends and is home some weekdays: solar covers a third to a half of annual EV energy, at a marginal cost of 0p/kWh. The grid, ideally on an off-peak EV tariff, does the rest.
What does the setup cost?
Solar is not cheap, and it should be bought for the whole-house case rather than for the car alone. A 4.5kW system with a 3kW battery runs to about £9,800 installed as of mid-2026, according to the Federation of Master Builders; panels-only systems cost less.2 Payback comes from avoided grid electricity (at 26.11p/kWh from July 2026), export payments via the Smart Export Guarantee, and, yes, free miles.
The EV angle strengthens the case rather than making it: every kWh you put in the car is a kWh you would otherwise have bought at 8 to 26p. Households with an EV use more electricity than average, which means they self-consume more of what their roof makes, which is exactly what solar economics rewards.
Is your roof suitable?
The quick checks before any installer visit: orientation (south is best, east-west split is a decent second), shading (chimneys, trees and the neighbour’s extension all cost you output), roof space (a 4kW system needs roughly 15 to 20 square metres of clear roof), and tenure (you need to own the roof, which rules out most renters and many leaseholders). Flat roofs work with angled frames. A north-facing main roof usually kills the case.
What is the Smart Export Guarantee worth?
When your panels generate more than the house and car can use, the surplus goes to the grid and your supplier pays you for it under the Smart Export Guarantee. SEG rates are set by each supplier and vary widely, so the golden rule of solar economics applies: self-consumption beats export. Every kWh you put into the car displaces electricity bought at 8 to 26p, while exported kWh earn only the SEG rate. An EV, being a large flexible load that can soak up midday surplus, is close to the ideal solar companion.1
Do you need a home battery?
Not necessarily. Without a battery, solar charging works when the car is home in daylight, which suits remote workers and weekend drivers. A home battery time-shifts your surplus into the evening and overnight, which suits commuters, but it adds thousands of pounds to the system (the FMB’s roughly £9,800 figure for a 4.5kW system includes a 3kW battery).2 Run the house-plus-car numbers both ways before deciding; for many households the battery pays back more slowly than the panels.
Is solar EV charging worth it for you?
Worth it if: you own your roof, it faces roughly south without shading, you are home by day often enough to catch the surplus, and you were already considering solar for the house.
Not worth it if: the car is away every weekday, your roof is shaded or north-facing, or you rent. In those cases an off-peak EV tariff delivers most of the saving for none of the capital. For the grid-side numbers, see how much it costs to charge an electric car at home, and for the hardware, our best home EV chargers guide.
- Key facts
- 4kW system annual output
- 3,000-3,500kWh
- Annual EV demand (8k miles)
- About 2,300kWh
- Solar system cost
- About £9,800
- Marginal cost of solar charging
- 0p/kWh
Sources
- Energy Saving Trust, solar panels advice Accessed 18 July 2026
- Federation of Master Builders, solar panel costs Accessed 18 July 2026
- myenergi, Zappi Accessed 18 July 2026
- Hypervolt Accessed 18 July 2026