Updated — Revised SEG export rate figures for 2026
Solar Panels and EV Charging: Free Tesla Miles?
Free miles from the roof
Solar panels can charge a Tesla at essentially zero marginal cost — sunlight in, miles out, no electricity bill for the energy you generate yourself. For UK households with solar already installed, or weighing it up, the proposition has become markedly more practical in the last two years.
How Solar EV Charging Works
The basic concept is simple: solar panels on your roof generate electricity during the day. Instead of exporting that excess electricity back to the grid (where you'd earn the Smart Export Guarantee rate of ~4–6p/kWh), you divert it to your EV charger.
There are two main approaches:
1. Solar Diverting (Recommended)
A solar-compatible charger has a CT clamp on your meter that monitors generation in real time. When the panels produce more than the house is using, the charger sends the surplus to the car.
It only charges when solar is available, and never pulls from the grid unnecessarily. We tracked a 4kW system paired with a Zappi GLO for six months and it covered roughly 60% of a typical commuter's charging between April and September.
2. Scheduled Daytime Charging
Without solar diverting, you schedule charging for peak sunshine hours (roughly 10am–3pm). It's a blunter tool: the house draws at the same time, and a cloudy day means you pull from the grid.
What Does It Cost?
If You Already Have Solar Panels
The incremental cost is a solar-compatible charger:
| Charger | Price | Solar Feature |
|---|---|---|
| Ohme Home Pro | £535 | Built-in solar diverting |
| Wallbox Pulsar Max | £496 | Eco-Smart mode (requires Power Meter, ~£150 extra) |
| Tesla Wall Connector | £478 | No native solar diverting |
| myenergi Zappi GLO | £750 | Best-in-class solar diverting |
Add £300–600 for installation, and the total to add solar-compatible EV charging to an existing solar setup lands at £800–1,400.
If You're Starting from Scratch
A full solar + EV charging system costs more upfront, and returns more over time:
| Component | Typical Cost |
|---|---|
| 4kW solar panel system (10 panels) | £5,000–£7,000 |
| 6kW solar panel system (15 panels) | £7,000–£9,000 |
| Battery storage (10kWh) | £4,000–£6,000 |
| Solar-compatible EV charger + install | £800–£1,400 |
| Total (panels + charger, no battery) | £6,000–£10,000 |
| Total (panels + battery + charger) | £10,000–£16,000 |
Solar panels are VAT-free in the UK, which takes £1,000–2,000 off the headline price.
How Much Will You Actually Save?
Three variables set the answer: system size, annual mileage, and when the car is plugged in.
Realistic UK Solar Generation
A typical 4kW system in the UK generates around 3,400 kWh per year. Of that, roughly 40–50% can go into the car; the rest powers the house or gets exported.
That's 1,400–1,700 kWh to the car, which works out to:
| Metric | Value |
|---|---|
| Free miles per year | ~5,600–6,800 |
| Electricity saved | 1,400–1,700 kWh |
| Value at standard rate (28p/kWh) | £390–£475/year |
| Value at off-peak rate (7p/kWh) | £98–£119/year |
Key insight: solar savings are far larger on a standard tariff. On a 7p/kWh off-peak rate, each kWh of solar only offsets 7p instead of 28p.
A smaller 3kW system can be more cost-effective for EV charging than a 6kW one — the surplus-to-car ratio is often better matched to daily driving of 20–30 miles.
With Battery Storage
A battery stores daytime generation so the car can charge overnight. Solar self-consumption for the car jumps from ~40–50% to ~70–80%.
With a battery, annual EV charging savings against standard rates rise to around £550–£700.
Payback Period
| Setup | Cost | Annual Savings | Payback |
|---|---|---|---|
| Charger only (have panels) | £800–1,400 | £300–475 | 2–4 years |
| Panels + charger | £6,000–10,000 | £600–900 | 7–11 years |
| Panels + battery + charger | £10,000–16,000 | £900–1,300 | 8–12 years |
Savings include both EV charging and general household electricity reduction. Solar panels typically last 25+ years.
Considering solar-compatible charging? See our ranked guide: Best EV Charger for Solar Panels | Get free installation quotes →
Which Chargers Support Solar Diverting?
Not every charger can divert solar. The ones we've tested fall into four camps:
Ohme Home Pro — Built-In Solar
The Ohme Home Pro includes solar diverting at no extra cost. It tracks generation and adjusts charging power to match the available surplus. For most buyers it's the cheapest route into solar-compatible charging.
Wallbox Pulsar Max — Eco-Smart Mode
The Wallbox Pulsar Max handles solar diverting through Eco-Smart, but only with the separate Wallbox Power Meter (~£150). Fitted, it tracks daytime surplus cleanly.
Tesla Wall Connector — No Native Support
The Tesla Wall Connector has no built-in solar diverting. The Tesla app can schedule daytime charging, but nothing modulates to match generation. True integration needs a Powerwall or a third-party energy manager.
myenergi Zappi GLO — The Solar Specialist
The Zappi GLO runs the most thorough solar-diverting implementation we've tested. It was designed around solar first, and the granularity shows. If solar is the priority and the budget stretches, nothing else matches it.
Stacking solar with a smart tariff
The cheapest combined setup is solar panels plus a smart tariff such as Octopus Intelligent Go:
- Daytime: charge from solar (free)
- Overnight: top up on off-peak (~7p/kWh)
- Never: pay standard rates (28p/kWh)
On that mix, a Tesla Model 3 covering 8,000 miles a year runs to under £70 in annual charging — less than a single tank of petrol.
Is It Worth It?
Solar + EV makes sense if:
- You already have solar panels (the charger upgrade is cheap and pays back in 2–4 years)
- You're at home during the day (work from home, retired) so the car is available to charge when the sun is shining
- You're planning to stay in your property for 7+ years (to benefit from the payback period)
- You're on a standard electricity tariff (the savings per kWh are much higher)
It's less compelling if:
- You're already on a 7p/kWh off-peak tariff (the incremental saving from solar is small — see our UK EV Charging Cost Index for full tariff cost data)
- Your car is away from home during daylight hours every day (no car to charge when panels are generating)
- You rent your property (you can't install panels without landlord permission, and you may not stay long enough for payback)
Getting Started
If you're interested in solar EV charging, here's the order to do things:
- Get a smart tariff first — this is free and saves you money immediately
- Install solar panels if you don't have them — get 3 quotes from MCS-certified installers
- Choose a solar-compatible charger — the Ohme Home Pro offers the best value for solar diverting
- Consider battery storage later — it improves solar utilisation but the payback is longer
When you're ready, compare the chargers we've tested, or — no obligation, no sign-up.