Solar Panels for EV Charging Calculator
Work out how many solar panels cover your electric car's daily charging needs. Enter the distance you drive each day, your EV's energy consumption in kWh per 100 km, your local peak sun hours, the panel wattage you plan to install and your system's estimated efficiency. You get the panel count, total array size in kilowatts, roof area and estimated annual production from that array.
Last updated: May 2026
Enter your daily driving distance, EV efficiency and peak sun hours above.
Panel count rounded up to a whole number · area assumes ~2 m² per panel (typical 400 W residential panel) · annual production = panels × daily output × 365 days
How to size solar panels for EV charging
Sizing solar panels to cover EV charging comes down to three numbers: how many kilowatt-hours your car uses each day, how many kilowatt-hours each panel produces each day, and the ratio between them. The daily energy need is simply your distance multiplied by your car's consumption rate. Daily panel output is the panel's rated wattage multiplied by your local peak sun hours and your system's efficiency factor. Divide the first by the second and round up to a whole panel.
Step 1 - daily energy need
Multiply your daily driving distance in km by your EV's consumption in kWh per 100 km, then divide by 100. A car using 16 kWh/100 km driven 50 km/day needs 8.0 kWh. This is the target your panels must hit on an average day. For planning purposes, use a representative weekday distance rather than your peak trip - the system is sized to the average, and occasional longer days simply draw from the grid or a battery bank.
Step 2 - daily output per panel
Each panel produces (Wp ÷ 1000) × PSH × system efficiency kWh per day. A 400 W panel with 4.0 peak sun hours and 80% system efficiency makes 0.4 × 4.0 × 0.80 = 1.28 kWh/day. System efficiency covers inverter conversion losses (typically 4 to 6%), resistive losses in DC cabling (1 to 3%), soiling from dust and bird droppings (1 to 2%), and temperature derating - silicon panels lose roughly 0.4% of output per degree Celsius above 25°C, which matters in warm climates. An 80% figure is a reasonable middle estimate; well-maintained modern string inverter systems often reach 82 to 85%.
Step 3 - panel count and array size
Divide daily energy need by output per panel and round up. For the example above: 8.0 ÷ 1.28 = 6.25, rounded up to 7 panels. Seven 400 W panels give a 2.8 kW array and produce roughly 3,270 kWh/year at those conditions - enough to cover about 20,000 km of EV driving. The array will produce more in summer and less in winter; if you are connected to the grid with net metering, the annual total is what matters most. For off-grid or battery-buffered charging, size to the winter low PSH for your region.
EV efficiency: how much energy your car uses per 100 km
EV efficiency varies considerably by vehicle size, aerodynamics and driving conditions. Real-world consumption is typically 10 to 20% higher than the official WLTP figure in mixed urban and highway driving, and significantly higher in cold weather when the battery heater draws current. Use your own recent trip data if you have it, or the mid-range figure in the table below as a starting point.
| EV type / example models | Consumption (kWh/100 km) | Notes |
|---|---|---|
| Small city EV (Mini Electric, Fiat 500e, Citroën ë-C3) | 13 to 15 | Light weight and short range; low consumption |
| Compact EV (Renault Zoe, Peugeot e-208, VW ID.3) | 15 to 17 | Urban-focused; good efficiency |
| Mid-size saloon (Tesla Model 3, Hyundai IONIQ 6, BMW i4) | 14 to 16 | Aerodynamic; among the most efficient in their class |
| Mid-size crossover (Tesla Model Y, Kia EV6, Hyundai IONIQ 5) | 17 to 20 | Popular family choice; moderate consumption |
| Large SUV (Ford Mustang Mach-E, Audi Q4 e-tron, VW ID.4) | 19 to 23 | Higher frontal area increases consumption at speed |
| Electric pickup (Ford F-150 Lightning, Rivian R1T) | 26 to 35 | Heaviest category; largest panel array needed |
Worked example
A household in the Netherlands (PSH ≈ 2.8 annual average) drives a VW ID.3 consuming 17 kWh/100 km for 45 km/day. Daily need is 45 × 17 ÷ 100 = 7.65 kWh. Each 400 W panel produces 0.4 × 2.8 × 0.80 = 0.896 kWh/day. Panels needed: ceil(7.65 ÷ 0.896) = ceil(8.5) = 9 panels. The resulting 3.6 kW array covers about 18 m² and produces an estimated 2,936 kWh/year. In practice, Dutch winter months yield as little as 0.7 PSH, so January and February will need grid top-up or a battery buffer; the summer months more than compensate, producing enough annual surplus for the annual balance to work out.
Typical panel counts by scenario
| Scenario | Daily km | kWh/100 km | PSH | Result (400 W panels, 80%) |
|---|---|---|---|---|
| City commuter, N. Europe (UK, NL, DE north) | 40 | 16 | 2.8 | 9 panels - 3.6 kW |
| City commuter, C. Europe (DE south, PL, AT) | 40 | 16 | 3.5 | 6 panels - 2.4 kW |
| Mixed driving, S. Europe (ES, PT, IT, GR) | 60 | 18 | 5.0 | 7 panels - 2.8 kW |
| Mixed driving, US Northeast / Midwest | 60 | 18 | 4.2 | 8 panels - 3.2 kW |
| Mixed driving, US Southwest (AZ, NV, CA) | 60 | 18 | 6.0 | 6 panels - 2.4 kW |
| High-mileage driver, large SUV, C. Europe | 100 | 22 | 3.5 | 16 panels - 6.4 kW |
Frequently Asked Questions
How many solar panels does it take to charge an electric car?
Most EV owners driving 40 to 60 km per day need between 5 and 10 residential panels (2 to 4 kW) to cover their daily charging energy. The exact count depends on three things: your daily distance, your car's efficiency (typically 14 to 22 kWh per 100 km for common models), and your local peak sun hours. A compact EV doing 50 km in central Europe, where 3.5 to 4.0 PSH is typical, needs roughly 7 to 8 panels at 400 W each. In the sunnier US Southwest the same car might need only 5 or 6 panels.
Can solar panels fully cover my EV charging?
Yes, for most typical driving patterns a properly sized grid-tied array can cover 100% of your EV's annual charging energy - but not necessarily every individual day. A grid-tied system with net metering banks the summer surplus to offset winter shortfall through the grid. An off-grid or battery-backed setup needs to be sized to the winter low PSH rather than the annual average, which typically means 40 to 80% more panels depending on your latitude. This calculator gives you the panel count for your average daily need; for winter autonomy, use the winter low PSH value from the peak sun hours reference.
Does my EV need to connect directly to the solar array?
No, and a direct connection is rarely practical in a home setup. The solar array feeds the household circuit through an inverter, and your EV charger draws from the same circuit like any other appliance. You do not need a dedicated panel-to-charger cable. What matters is that the array produces at least as much energy over the day, or the billing year with net metering, as your EV uses. Some smart inverters and EV chargers do support solar-matched charging - dynamically throttling the charge rate to match real-time solar output - which maximises self-consumption and reduces both export and grid import, but this is an optional optimisation, not a requirement.
What panel wattage is best for a solar EV setup?
For most residential roofs, 400 to 450 W panels offer the best balance of output per panel, standard mounting hardware compatibility and price per watt. Larger panels (550 to 600 W) reduce the panel count for the same array size, but they need wider frames that may not fit standard roof mounts and cost more per unit. Smaller panels (300 W) are fine but require more of them for the same total output. If your roof area is the main constraint, the highest-wattage panel that fits your rafter spacing is usually the right choice. If cost per installed watt is the constraint, 400 to 450 W panels are typically the sweet spot in residential markets.
Should I add a home battery to cover overnight EV charging?
If you charge your EV overnight, the solar production from the day needs to be stored until you plug in - a home battery does that. Without a battery on a grid-tied system, solar offsets your EV's night charging indirectly through net metering: you export what you make during the day and import it at night. Where net metering pays close to the retail rate, a battery rarely saves enough to justify its extra cost purely on financial grounds. Where the feed-in rate is much lower than the retail rate, storing solar for later use (including overnight EV charging) becomes financially worthwhile. For off-grid systems, a battery is essential - size it to cover at least one night's EV charging demand plus any other overnight loads.