The short answer: Solar panels and an EV are the best double act in home energy. Charging your electric car on solar power could save you an extra £600–£1,200 per year on top of your standard solar savings — and reduce your car's running cost to near zero during sunny months. This guide explains exactly how it works, what it costs, and how to set it up correctly.
As EV adoption accelerates across the UK, more homeowners are realising that solar panels don't just cut your electricity bill — they can essentially give you free fuel for your car. A typical UK driver covers 7,000–10,000 miles per year. At public charging rates of 40–75p/kWh, that's £500–£1,000/year. Charge at home on solar-generated electricity and that figure drops dramatically.
How Solar + EV Charging Works
During daylight hours, your solar panels generate electricity. Any power your home doesn't use immediately can go to one of three places: the national grid (earning you the Smart Export Guarantee rate), a home battery, or your electric car.
The key is getting the timing right. Most EV owners are at home during the day less often than they'd like — which is where smart charging technology becomes valuable. A smart EV charger can detect when your solar panels are generating surplus electricity and automatically divert it to your car, rather than exporting it to the grid at a low SEG rate.
The core principle: Every kWh you put into your EV from solar costs you nothing and earns you nothing in SEG. But it displaces a kWh you'd otherwise buy at 24.5p, plus a kWh you'd buy at 40–75p at a public charger. The value of solar-charged EV miles is significantly higher than standard solar savings.
The Numbers: How Much Can You Save?
Let's model the savings for a typical UK household with a 4kW solar system and an EV driving 9,000 miles/year, using a home charger:
| Scenario | Annual Charging Cost | Saving vs Public Charging |
|---|---|---|
| Public rapid charger (avg 55p/kWh) | £990 | Baseline |
| Home charger, grid electricity (24.5p/kWh) | £441 | £549/year |
| Home charger, 50% solar-sourced | £220 | £770/year |
| Home charger, 80% solar (with battery) | £88 | £902/year |
Add this to the standard solar savings on your household electricity (£500–£700/year for a 4kW system) and the combined annual benefit of solar + EV can reach £1,200–£1,600/year for families who drive a reasonable amount.
What Equipment Do You Need?
1. A solar panel system (minimum 4kW recommended)
A 4kW system generates around 3,400–3,800 kWh/year in the UK. An EV doing 9,000 miles/year needs roughly 1,800 kWh. That's roughly half your generation going to the car — which is workable. If you drive more, or have two EVs, consider a 5kW or 6kW system.
2. A smart EV charger with solar divert capability
Not all EV chargers can detect and prioritise surplus solar power. You specifically need one with solar divert (sometimes called "eco mode" or "green charging"). Popular models that support this in the UK include:
- Zappi by myenergi — the most popular solar-divert charger in the UK. Three modes: Fast (grid), Eco (solar priority + grid top-up), Eco+ (solar only, pauses if no surplus)
- Ohme Home Pro — smart charger that integrates with solar and Octopus Energy
- Indra Smart PRO — supports solar divert and vehicle-to-grid (V2G) in some EVs
A Zappi typically costs £700–£900 installed, versus £400–£600 for a standard 7kW home charger.
3. A home battery (optional but impactful)
A battery lets you store solar energy generated during the day and use it to charge your EV in the evening — which is when most people actually plug in. Without a battery, your car can only benefit from solar when you're home during daylight hours. With a battery, you capture surplus solar throughout the day and charge the car whenever it's convenient.
Recommended Setup: 4kW Solar + 5kWh Battery + Zappi Charger
An 8-year payback on a system that lasts 25+ years means roughly 17 years of pure financial benefit after the system pays itself off. The total lifetime saving on this setup could exceed £23,000.
Does the Direction of Your Roof Matter More with an EV?
Yes. With a standard solar installation, a south-facing roof maximises your savings. But with an EV, a west-facing roof component becomes particularly valuable. West-facing panels generate their peak output in the afternoon — which better aligns with when EVs are typically parked at home and can be charged.
Many solar installers now recommend split-orientation systems for EV owners — panels on both south and west-facing roof planes. You sacrifice some peak summer output but get better alignment with evening EV charging patterns and improve generation on overcast days.
What About Vehicle-to-Grid (V2G)?
Vehicle-to-grid technology allows your EV battery to export electricity back to your home (or the national grid) when needed. This is sometimes called V2H (vehicle-to-home) or V2G. In theory, your EV becomes a 40–100kWh battery for your house — far larger than any domestic home battery.
In the UK, V2G is still emerging. The Nissan Leaf has supported it longest, and the Quasar charger from wallbox enables it. Some newer EVs (notably the BYD range and certain Ford models) are adding V2H capability. It's worth asking about if you're buying a new EV — but don't let its absence stop you getting solar now. Standard solar + Zappi delivers most of the benefit today.
Can I Add Solar if I Already Have an EV Charger Installed?
Yes — and it's simpler than most people expect. If you have a standard home charger (Ohme, Pod Point, etc.), your installer can add a solar system and in many cases configure solar divert through the existing charger's app, or you can replace the charger with a solar-compatible model. Your Distribution Network Operator (DNO) permissions from your original charger installation typically still apply.
Get a Solar + EV Charging Quote for Your Home
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Get Free Quotes →Frequently Asked Questions
Can I charge my EV entirely on solar power?
In summer, very possibly — a 4kW system in South England generates 500–600 kWh per month, and a typical EV uses 300–400 kWh/month for average mileage. In winter, solar output drops to 100–150 kWh/month, so you'll need to top up from the grid. A home battery significantly extends how often you're running on solar throughout the year.
Does charging an EV affect my solar panel warranty?
No — your solar panel warranty (typically 25 years performance, 10–12 years product) is entirely separate from how you use the electricity generated. Charging an EV has no impact on your panels or inverter warranty.
Do I need to tell my installer I have an EV?
Yes — and it's important to do so upfront. An installer who knows you have (or plan to get) an EV will size your system appropriately, advise on west-facing panels, and ensure your inverter and any battery are specified to handle higher overall consumption. Designing for future EV ownership is much easier than retrofitting later.
Is there a grant for EV chargers in 2026?
The OZEV (Office for Zero Emission Vehicles) Electric Vehicle Chargepoint Grant ended for homeowners in 2022 but continues for renters and flat owners in some circumstances. The Workplace Charging Scheme still applies to businesses. For most homeowners, there is currently no grant — but 0% VAT still applies to home charge point installation, saving you 20%.
What's the best solar system size if I have two EVs?
For two EVs with average mileage, you'll want a minimum 5kW system, ideally 6–8kW if your roof allows. Factor in approximately 1,500–2,000 kWh of additional annual generation per EV above your household baseline.