Charging an EV From Solar: What You Actually Save
2 min read
Charging an EV from your own solar panels sounds like free fuel, and in a narrow sense it is, but most UK drivers won’t be able to do most of their charging that way. Here’s why, and what the savings actually look like once you account for it.
Why most solar-charged miles aren’t really solar-charged
EVs are usually charged overnight, when solar panels aren’t generating anything. Unless you’re specifically home during the day and set your car to charge then, or you have a battery and a smart charger that shifts generation into the evening, most of your charging will still come from the grid, just at whatever rate your tariff gives you overnight.
Where solar genuinely helps
- Daytime charging. If you work from home or charge during the day (weekends, retired households, second cars), solar can directly offset a real share of charging costs.
- Smart/solar-diverting chargers. Some EV chargers can automatically direct surplus solar generation to the car rather than exporting it, topping up “for free” whenever there’s spare generation.
- Combined with a battery. Stored solar can be released to charge the car in the evening instead of drawing from the grid.
The bigger saving is the tariff, not the panels
Even without solar, home charging is dramatically cheaper than public charging:
| Where you charge | Typical cost per mile |
|---|---|
| Public rapid charger | 20p to 25p |
| Home, standard tariff | 7p to 8p |
| Home, overnight EV tariff (e.g. Octopus Go) | around 3p |
Switching from public charging to a cheap overnight home tariff saves most of the money. Solar generation on top of that captures whatever slice of your charging happens to fall during daylight hours.
The bottom line
Don’t buy an EV charger expecting your solar panels to fuel it for free, most of your mileage will still be grid-charged overnight. What solar plus a smart charger does is shave a genuine chunk off an already-cheap home charging bill. See our full EV charger cost and savings guide for installation pricing and grant eligibility. Get matched with installers for solar, an EV charger, or both.