The short answer

For an average driver, the figure lands at roughly 5 to 10 panels at today's ~440 W modules — fewer for an efficient car in a sunny climate, more for a thirsty one in cloud. The U.S. Federal Highway Administration puts average annual driving at about 13,500 miles; Kelley Blue Book uses ~12,200. At a typical EV efficiency of 0.25–0.35 kWh per mile, that's 3,000–5,000 kWh a year — the number EnergySage and SolarReviews both converge on, translating to roughly six panels for an average car.

Why it's less than you fear

People brace for an EV to double their solar bill, but a year of driving is smaller than a home's lighting, heating and appliances. Charging a typical EV adds about a third to a half to a 10,000 kWh household — not a second house. Modern cars are efficient: a Tesla Model 3 RWD returns about 4.4 miles per kWh in real-world testing (What Car?, 2024), and the whole Tesla range averages around 34 kWh per 100 miles. The energy to drive a normal year is genuinely modest — that's why a handful of panels covers it.

The flexibility advantage

Here's the part the bare number misses, and the reason an EV is the best thing to pair with solar: you choose when to charge. Most home loads happen at breakfast and after dark, when the panels aren't producing — but a car can be told to charge at midday, soaking up surplus solar that would otherwise be exported for a few cents. That flexibility lets a daytime-charged EV run almost entirely on self-generated power, no battery required.

And the car itself is an enormous battery. A Nissan Leaf holds 40 kWh, a Tesla Model Y 75 kWh, a Ford F-150 Lightning up to 131 kWh — several times the size of a typical 10–13.5 kWh home battery. With bidirectional charging, that pack can even run the house: Ford's Intelligent Backup Power uses the Lightning to power a home during an outage.

What changes the number

Three things move it. Efficiency is the biggest: an electric pickup at ~2 miles per kWh needs roughly double the panels of an efficient hatchback for the same trips. Distance scales linearly — a 20,000-mile-a-year driver needs about three times a 6,000-mile one. And sun hours: the same car might want six panels in Phoenix and ten in a cloudy north. The calculator above bakes in all three; try a truck versus a sedan and watch the count jump.

The car stops being just a car

The interesting shift isn't the panel count — it's that the driveway now holds a battery bigger than the house's. As bidirectional charging spreads from the F-150 Lightning to mainstream models, the question flips: not "how many panels to charge the car," but "how much of the home can the car run." A daytime-charged EV becomes a way to time-shift solar into the evening without buying a wall battery at all.

So size the five-to-ten panels for the driving — but know you're really buying the most flexible load and the largest battery you'll ever own. The next question worth asking is whether you still need a home battery at all.

Common questions

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