Solar Panels + EV Charging — Power Your Car From the Sun

Daytime Charging: The Big Savings

The average UK driver covers around 7,400 miles per year. An electric car uses roughly 3–4 miles per kWh, meaning you need approximately 1,850–2,500 kWh per year to charge it. At the current grid rate of 24.5p/kWh, that costs £453–£613 per year from the grid.

From solar panels? Effectively free. If your car is at home during the day (parked on the drive, WFH, or retired), you can charge directly from your solar panels at zero marginal cost. Even if your car is only home 3–4 days per week, you can still cover 60–70% of your charging from solar.

Compared to petrol at £1.45/litre, the savings are even more dramatic. A petrol car doing 7,400 miles at 40mpg costs roughly £1,600/year in fuel. Solar-charged EV: £100–£200 (grid top-up for nights and winter). That is a saving of over £1,400/year on fuel alone.

Smart Charger Recommendations

A solar-compatible smart charger can automatically adjust the charging rate based on how much solar energy your panels are generating. This ensures your car only charges on surplus solar, rather than pulling expensive grid electricity.

Zappi (by Myenergi)

The Zappi is the most popular solar-compatible EV charger in the UK. Its key feature is “Eco” and “Eco+” modes that automatically match charging speed to available solar surplus. In Eco+ mode, it only charges when there is enough solar generation — drawing zero from the grid.

• 7kW (single phase) or 22kW (three phase) options
• Eco+ mode: charges only from solar surplus
• Eco mode: tops up from grid if solar is insufficient
• Price: £800–£1,100 installed
• Works with all EVs and any solar system (no brand lock-in)

Ohme Home Pro

The Ohme Home Pro focuses on smart tariff integration. It automatically charges when electricity is cheapest (e.g., overnight on Octopus Go or Intelligent Octopus). While it does not have a dedicated solar surplus mode like the Zappi, it integrates with home energy management systems.

• 7kW single phase
• Automatic smart tariff optimisation
• App-controlled scheduling
• Price: £700–£950 installed
• Best paired with a time-of-use tariff

Other Options

The Hypervolt and Wallbox Pulsar Plus are also solid choices with app control and scheduled charging. For dedicated solar diversion, the Zappi remains the market leader.

Sizing Your Solar System for EV Charging

Adding an EV to your household typically increases annual electricity demand by 1,850–2,500 kWh. To accommodate this with solar:

• Without EV: 3–4kW system is usually sufficient for a typical home
• With EV (occasional daytime charging): 4–5kW system recommended
• With EV (daily daytime charging, WFH): 5–6kW system ideal
• Two EVs or EV + heat pump: 6kW+ system with battery storage

A 5kW system generates roughly 4,000–4,500 kWh per year in the south of England, or 3,500–4,000 kWh in Scotland. After household use (1,500–2,000 kWh), the surplus is enough to cover most or all of your EV charging for 7–8 months of the year.

Do You Need a Battery as Well?

If your car is home during the day, you may not need a battery — the car itself acts as an energy sink for your surplus solar. However, a home battery is useful if:

• Your car is away during peak solar hours (at work)
• You want to store solar energy for evening household use
• You are on a time-of-use tariff and want to arbitrage cheap overnight rates

Vehicle-to-Grid (V2G) technology, which lets your EV battery power your home, is still limited in the UK but is expected to become mainstream by 2027–2028. The Nissan Leaf and some upcoming models support V2G with compatible chargers.

Recommended EV Charging Accessories

If you are not ready for a hardwired charger, or need a portable option for charging away from home, these accessories are useful:

• Type 2 to Type 2 EV Charging Cable (5m) — essential for public chargers that do not provide a tethered cable
• Portable EV Charger (3-pin plug, 2.3kW) — emergency/overnight charging from a standard socket
• EV Charging Cable Bag — keep your boot tidy