EV Charging from Solar Calculator

How many solar panels to charge an electric car?

Charging an EV from solar comes down to matching two numbers: how much energy your driving needs each day, and how much your panels can generate. The appeal is real — fuelling a car on sunlight you've already paid for is dramatically cheaper than petrol or grid electricity — but the size of array it takes surprises people, because cars are energy-hungry compared with most household appliances. The good news is the maths is simple once you know your daily mileage.

Pairing solar with an electric car is one of the most satisfying things you can do with a rooftop array: your daily driving stops costing anything at the pump or the meter and starts running on sunlight you already own. But it also raises a practical puzzle that trips up newcomers — cars are charged mostly at night, while solar is generated in the day, and a home fast-charger can draw more power in an instant than your whole array produces. Bridging that gap is what turns "I have solar and an EV" into "my solar actually fuels my EV." The numbers below show how big an array your driving really needs, and the timing strategies — daytime charging, net metering, or a battery — that determine whether your panels genuinely power the car or merely offset part of the bill.

Work out your daily charging energy

EVs use roughly 0.3 kWh per mile (about 0.2 kWh/km), varying by model — efficient cars nearer 0.25, large SUVs and trucks nearer 0.4–0.5. The average driver covers around 38 miles a day, which works out to roughly 13 kWh per day, or about 90 kWh a week. Multiply your own daily mileage by your car's kWh-per-mile figure (on its window sticker or spec sheet) to get your real daily charging need.

Translate that into panels

Divide your daily kWh by your local peak sun-hours to get the array size in kW, then divide by your panel wattage for a panel count. For example, 13 kWh a day in a location with 5 peak sun-hours needs about 2.6 kW of panels — roughly six to eight modern panels — to cover the car alone, on top of whatever your home uses. A short commuter might need only 3–4 panels; a long-distance driver or a thirsty vehicle could need 10 or more. The calculator above does this for your figures.

Charging levels and why timing matters

• Level 1 (a standard household socket) adds only a few miles of range per hour — fine for low-mileage drivers charging overnight, too slow for many.
• Level 2 (a 240V home charger, typically ~7 kW) adds around 25 miles of range per hour and is what most home EV owners install.

Here's the catch for solar: a 7 kW Level 2 charger draws more than most home arrays produce at any instant, and cars are usually charged at night when there's no sun. So "charging from solar" really means either charging during the day when the sun is up, or — more practically — using net metering or a home battery to bank daytime solar and draw it down for overnight charging. Without one of those, your overnight charging is really grid power, even if your panels exported an equivalent amount earlier in the day.

Why daytime or battery charging matters most

As with the rest of solar economics in 2026, self-consumption is king. If you can schedule charging for daylight hours (many EVs and chargers let you set a timer), you use your solar directly at full value instead of exporting it cheaply and buying it back at night. A home battery achieves the same by storing midday surplus for an overnight charge. Where export rates are low — California's NEM 3.0, the UK, Pakistan — this timing is the difference between solar genuinely fuelling your car and merely offsetting part of the bill.

Frequently asked questions

Typically 4–10 panels depending on your mileage and local sun. An average commuter needs around 2–3 kW of panels (roughly 6–8 panels) just for the car, in addition to household use. Enter your mileage and location above for a tailored figure.

During the day, yes — if your array output is high enough and you charge while the sun is up. Because a Level 2 charger draws a lot and most charging happens at night, many owners rely on net metering or a home battery to use daytime solar for overnight charging.

Once the panels are paid off, solar-charged miles are essentially free, versus paying grid rates or petrol prices. Even before payback, using your own solar to charge is far cheaper than buying grid power — and far cheaper than fuel, which is a large part of the EV savings case.

A battery helps if you mostly charge at night and your export rate is low, since it lets you store cheap daytime solar for an evening charge rather than exporting it and buying back. If you can simply charge during daylight, you may not need one. It depends on your schedule and tariff.