For households with both an electric vehicle and solar panels, the two technologies work together in a way that significantly amplifies the value of each. Solar panels give you cheap or free daytime electricity; your EV is a large energy consumer that can soak up surplus generation. A smart EV charger is the glue that makes it work seamlessly.
Why Solar + EV Is Such a Good Combination
A typical EV requires 3,000–5,000 kWh of electricity per year for average UK mileage (8,000–12,000 miles). At grid electricity prices of 28p/kWh, that’s £840–£1,400/year. Charge the same EV from your solar panels at effectively 0p/kWh and the saving is enormous.
The key is matching charging time to solar generation: if you charge during daylight hours when your panels are generating, you can substantially reduce or eliminate the grid electricity used. A 4kW solar system generates an average of 10–17 kWh on a summer day — enough to add 40–70 miles of range (at 3.5 miles/kWh).
Smart EV Chargers for Solar Diversion
A standard EV charger simply draws from the grid at whatever rate you set. A smart solar-diverting charger monitors your solar generation and household consumption in real time and automatically charges your car using surplus solar power. This prevents your solar surplus from being exported at the modest SEG rate and instead puts it into your car at near-zero cost.
| Charger | Max Power | Solar Diversion | Smart Tariff | Price (installed) |
|---|---|---|---|---|
| Myenergi Zappi | 7.4kW | Yes (built-in) | Octopus compatible | £1,000–£1,400 |
| Ohme Home Pro | 7.4kW | Via app | Octopus, Agile, Go | £900–£1,200 |
| Pod Point Solo 3 | 7.4kW | No (grid only) | Limited | £800–£1,100 |
| Wallbox Quasar 2 | 7.4kW (V2G) | Via app | V2G capable | £1,500–£2,000 |
| Indra Smart Pro | 7.4kW | Yes | Octopus, Agile | £950–£1,300 |
The Zappi is the UK’s most popular solar-diverting charger. It operates in three modes: Eco+ (purely solar), Eco (solar + top-up grid power to maintain minimum 1.4kW charge), and Fast (full grid power).
Sizing Your Solar System for EV Charging
Adding an EV to your household changes the optimal solar system size significantly. A 4kW system is right for a home without an EV; adding an EV typically warrants upgrading to 5–6kW.
| Scenario | Recommended System | Annual Solar EV Charging | Annual Saving vs Grid |
|---|---|---|---|
| No EV | 4kW | — | £700–£900 |
| EV, low mileage (<8k miles) | 5kW | 1,500–2,000 kWh | +£420–£560 |
| EV, average mileage (10k miles) | 6kW | 2,000–3,000 kWh | +£560–£840 |
| EV, high mileage (15k+ miles) | 7–8kW | 2,500–3,500 kWh | +£700–£980 |
For maximum EV solar charging, a south-facing roof, 6kW+ system, and a smart charger set to Eco+ mode can realistically provide 50–70% of annual EV electricity from solar in the UK.
Battery Storage + Solar + EV: The Full Stack
Adding a battery to the solar + EV combination is increasingly compelling in 2026. A battery stores midday solar surplus and can release it in the evening for:
- EV charging via V2H (vehicle to home) if your EV supports it
- Home evening use
- Overnight EV charging from cheap tariff electricity
The Wallbox Quasar 2 supports V2G (vehicle to grid) bidirectional charging — your EV battery can power your home during grid outages or peak-price periods. This requires a compatible EV (Nissan Leaf, some Mitsubishi models, and more expected from 2025 onwards in Europe).
Smart Tariffs for EV Owners
If your solar covers daytime driving needs, optimise your night charging with a smart tariff:
- Octopus Intelligent Go: 7.5p/kWh overnight charging (vs 28p peak). Smart scheduling dispatches cheap charging automatically.
- Octopus Go: 7p/kWh between 11:30pm–5:30am.
- E.ON Drive: 7p/kWh overnight rate.
The combination of free solar daytime charging and 7p grid charging overnight can bring your effective per-mile energy cost below 2p — comparable to petrol at around £1.40/litre.
Frequently Asked Questions
Q: Can I charge my EV purely from solar panels?
A: Yes, during sunny periods. The Zappi in Eco+ mode only charges from surplus solar — if your 4kW system is generating 3kW and your home is using 1kW, the Zappi directs 2kW to your EV. On a clear summer day, you could add 8–12 kWh (30–50 miles) of range purely from solar.
Q: What size solar system do I need to charge an EV entirely from solar?
A: A 6–8kW system in the UK South can generate enough to cover 10,000–12,000 miles of EV driving annually from solar during the summer months. Year-round solar-only charging is not realistic in the UK — you’ll always need some grid top-up in winter.
Q: Does charging my EV with solar affect my SEG income?
A: Yes — electricity diverted to EV charging is not exported, so you earn nothing from it at SEG rates. But since you’re replacing 28p/kWh grid electricity with free solar, the economics strongly favour EV charging over exporting at 5–15p/kWh.
Q: Can I get a grant for an EV charger?
A: The OZEV EV chargepoint grant provides £350 off a home EV charger for eligible households (renters with a parking space and flat owners — homeowners are no longer eligible as of 2023). Check the current eligibility at GOV.UK as rules change.
Q: Is V2G (vehicle to grid) available in the UK?
A: V2G trials have been running in the UK since 2018, and commercial V2G tariffs are emerging in 2026 through OVO Energy and Octopus. Compatible vehicles include the Nissan Leaf and some Mitsubishi models. Wider vehicle compatibility is expected as EU standards mandate bidirectional charging on new EVs from 2026 onwards.