The connection between solar and an electric car is real, but it is not the one most people imagine. It runs through the tariff more than through the panels.
The obvious version, and why it only half works
The appealing idea is that your panels charge your car for nothing.
In practice, most people charge overnight, when the panels produce nothing. And a typical 4kW system produces less than a fast home charger draws, so even in daylight the panels rarely cover a full charging session on their own.
That does not mean solar and an EV do not go together. It means the benefit arrives differently.
The version that actually works
Three pieces:
An EV tariff gives you a cheap overnight window, often around 6.5p per unit against a standard rate of about 26.32p. That is where most of your charging happens and where most of the saving comes from.
Solar covers daytime household load and tops the car up when it happens to be home in daylight, which for many households is more often than they expect.
A battery, if you have one, charges overnight at the cheap rate alongside the car and runs the house through the expensive evening peak.
Suppliers have started allowing an EV import tariff to be paired with a proper export tariff, which was not previously possible. That matters, because it used to be a choice between cheap charging and decent export income.
Rates illustrate the structure. Last reviewed 4 Nov 2026. Check the supplier’s published terms.
How much of your charging can solar realistically cover?
It depends almost entirely on when the car is at home.
- Car home during the day, retired, working from home, second car used for short local trips: solar can cover a meaningful share of the charging over a year, particularly between March and September.
- Car out all day, charged overnight: solar covers very little of the charging directly. The saving comes from the tariff.
- With a home battery: solar charges the battery, the battery can feed the car in the evening. This closes some of the gap, though putting solar into a battery and then into a car loses a little at each step.
Be wary of any quote that assumes solar covers most of your EV charging without asking when the car is home. That assumption does most of the work in an optimistic savings figure.
Solar-matched charging
Most modern home chargers can be set to charge only from surplus solar, or to top up from the grid when solar is not enough. The names vary by manufacturer.
It is genuinely useful if the car is home during the day. Worth knowing:
- It needs a device that measures what is flowing in and out of your house. Make sure that is included rather than assumed.
- Charging rates from surplus solar are slow, because you are only using what is spare. That is fine for a car sitting on a driveway all day and no use if you need a fast turnaround.
- Some cars are fussy about very low charging currents. Ask whether yours is known to work with the charger being proposed.
An EV changes the solar case more than solar changes the EV case
This is the useful way round to think about it.
An electric car adds a large, flexible electricity load to a house. That raises the share of your solar generation you use at home instead of exporting, and self-consumption is the single biggest factor in whether solar pays. See payback.
So if you already have an EV, or are getting one, the case for solar is stronger than the standard sums suggest. And if you already have solar, an EV makes the existing system work harder without you spending anything more on it.
If you are getting both
A few practical points:
- Get the electrical work looked at once, not twice. If a charger and a solar system are both going in, having the same electrician assess the consumer unit and cable runs saves money and argument.
- Check your main fuse rating. A charger, a heat pump and a solar system together can push a property towards needing a supply upgrade. Better to find out before, not after.
- Mind the grid connection limit. A battery that can export counts towards the same threshold as your panels. See grid connection.
- Decide about the battery early. Retrofitting one is more expensive than including it, and it affects the inverter choice.