Solar EV Charging: How to Charge Your Car From Your Roof

Solar EV charging means using your rooftop solar generation to fill your car instead of grid electricity. Three approaches, simplest to most sophisticated:

1. Timer-based charging. Schedule charging across the middle of the day. If household consumption is modest, most of the charger's draw comes from your panels. Free, and works with any charger or even the portable cable.

2. Solar diversion (CT clamp). Chargers like the myenergi Zappi clip a current sensor at your meter and watch your export in real time. When the house exports, the charger ramps up to absorb the surplus; when a cloud passes or the kettle goes on, it ramps down. Maximum solar usage with no thought required.

3. Whole-system smarts. Pairing the charger with a home battery and a smart tariff lets the system juggle solar, cheap off-peak windows and peak export rates together. More moving parts, more value, more setup: see our battery guide for that layer.

An EV typically consumes 15-20kWh per 100km (roughly 3-4 miles per kWh). Whether your roof can cover your driving depends on your system size, your household's daytime consumption, and how often the car is home in daylight.

As a rule of thumb, a 4kW system (£5,500-7,500 installed, 0% VAT until 31 March 2027) generates meaningful midday surplus in most UK homes once the usual appliances are fed: enough to make a real dent in normal weekly mileage when the car is home to receive it. A larger array gives genuine headroom to run the house, heat water and charge the car simultaneously.

Two design notes:

• If the car is away at work all day, solar charging only works on weekends and work-from-home days; an off-peak EV tariff covers the weekday gap, and the two strategies stack happily.
• If you are buying solar and a charger together, tell the installer about the EV so the system is sized with charging in mind, and consider a hybrid-ready inverter if a battery is on the long-term list.

Two numbers drive the solar charging case in the UK (indicative June 2026):

• Grid electricity: 24.67p/kWh, rising to 26.11p from July 2026 under the Ofgem cap. At 3-4 miles per kWh, that is roughly 6.5-9p per mile at standard rates (off-peak EV tariffs do better).
• Diverted solar: you forgo the export payment, typically around 12p/kWh on the benchmark SEG tariff. That works out to roughly 3-4p per mile.

Indicative arithmetic; your consumption, tariff and SEG rate set the real figures.

So solar miles cost about half of standard-rate grid miles. Worth stating honestly: if you are on a very cheap overnight EV tariff, the gap between solar charging and off-peak charging narrows, and the best strategy is often both: solar by day when the car is home, off-peak top-ups by night when it is not.

For the petrol comparison, both sides pay standard-rate VED (around £195 a year for EVs since April 2025; petrol cars pay VED plus fuel duty inside the pump price, with petrol around £1.45/litre as an editorial estimate). Energy-for-energy, home-charged EVs come out well ahead per mile: run your own numbers in the EV vs petrol comparison.

myenergi Zappi: the UK solar-diversion benchmark, and UK-made. Eco+ mode charges from surplus only, pausing when clouds roll through; Eco mode blends solar with a trickle of grid. Works with any inverter brand via CT clamp.

Hypervolt: the premium UK option with solar capability and a polished app, for buyers who want diversion and design.

Ohme: approaches the same goal from the tariff side: its strength is squeezing the cheapest windows out of smart tariffs, which complements solar rather than tracking it watt-by-watt. From about £999 installed.

Wallbox: compact smart charger with optional solar capability and strong load management.

Typical fitting runs £800-1,200 within any installed price, so compare installed quotes rather than bare units: get installed quotes from local installers.