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 |
Where this calculator sits: the solar chain handing off to your car
This page straddles two clusters. Behind it is the solar sizing chain, which produces the panel count. Ahead of it is the EV cluster, which takes the kWh number and turns it into per-km costs and charging infrastructure choices. Running the full sequence in order keeps the inputs honest at every handoff:
- Account for every load before you size the array. EV charging is one item on the consumption list, not the whole list. If you plan to run the house and the car from the same array, the off-grid cabin sizing guide helps you total up every appliance circuit before you feed that combined figure into the rest of the chain.
- Use the gloomiest-month figure for your location, not the headline average. The difference is not trivial: Amsterdam averages 2.8 PSH annually but gets as little as 0.9 PSH in January. The peak sun hours reference lists both the annual average and the low-month value side by side, so you can see what each one demands from your array.
- Confirm how many kWh each panel actually delivers per day. Real output runs at 75 to 85% of the rated figure once inverter losses, cable resistance and temperature derating are applied. The solar panel output calculator lets you enter your wattage and sun hours and see the realistic daily kWh for any efficiency assumption.
- Bridge the timing gap between solar noon and evening charge-up. Panels peak around midday; most people plug their car in after work. For anything other than a grid-tied net-metering setup, that mismatch means you need storage. The battery bank sizing calculator works out the buffer capacity for your overnight charging load.
- You are here: convert km per day into a panel count and kWp total. This is the cross-cluster junction point. The daily distance and EV efficiency you enter produce a hard kWh target, which the calculator then maps to panel count and array size. The EV demand is a sharper input than most household estimates because it comes from an odometer, not a guess.
- Check the controller before you bolt on more panels. Every solar panel added to charge an EV raises the array's string current. The charge controller calculator shows whether your existing controller's rated input current covers the expanded array or whether you need to upsize it.
- Verify the inverter can sustain a fast home charger at full draw. A 7.4 kW AC charger is a sustained load, not a spike, and it easily outweighs every other appliance running simultaneously. Run the numbers through the inverter sizing calculator to confirm continuous capacity before buying hardware.
- Put a financial figure on the whole system. Once you know the array size and the fuel cost it displaces, the solar payback calculator shows how many years it takes to recover the capital, which lets you trim or expand the design with a real cost-per-year reference.
- Cross into the EV cluster for cost-per-km and charging infrastructure. Panel count is the solar side of the question. The other side is what your car actually pays per kilometre and how that compares to a public charge. The EV hub and the EV charging cost calculator carry the analysis from here.
One reason the EV demand makes a solid anchor for array sizing: it is quantitative from the start. Forty km per day at 17 kWh per 100 km is 6.8 kWh, full stop, no lifestyle assumptions required. That precision matters most in places like the Netherlands where a January array shortfall is predictable enough to plan around - you know the January number before you order a single panel.
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.
My array covers the EV in summer but falls short in winter. What should I do?
This is the normal situation for anyone in northern Europe: an array sized to the annual average PSH will be short by 40 to 60% in January and February. You have three options. First, size to the winter low PSH from the start, which means more panels but true year-round coverage without grid top-up. Second, accept seasonal shortfall and use the grid for EV charging in winter, relying on annual net metering to balance the account if your tariff allows it. Third, add a home battery sized to one or two nights of EV charging demand, so at least the overnight gap is covered by stored daytime solar even in winter. Most grid-tied EV owners in northern Europe use the second approach because net metering makes it financially straightforward; sizing to the winter low only makes sense when grid import is genuinely not available or very expensive.
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.
Methodology and sources
This tool calculates the number of solar panels needed to cover an EV's daily charging energy from the three factors that drive the result: how far you drive each day, how efficiently your EV converts electricity to distance, and how much usable solar energy your location produces per day.
- Method: daily charging energy (kWh) = daily distance (km) × EV efficiency (kWh per 100 km) ÷ 100; panel daily output (kWh) = panel wattage (W) ÷ 1000 × peak sun hours × system efficiency; panels needed = daily charging energy ÷ panel daily output, rounded up to a whole panel. System efficiency (default 80%) accounts for inverter losses, wiring losses, soiling and temperature derating combined.
- Standards and sources: peak sun hours (PSH) in the reference table are typical annual-average values derived from PVGIS (European Commission Joint Research Centre) and NREL NSRDB (US National Solar Radiation Database) for representative cities; use the winter low for worst-case sizing. EV efficiency figures follow manufacturer datasheets and real-world benchmarks for common models; 14 to 22 kWh per 100 km covers most passenger EVs.
- Assumptions and limits: the result is the panel count to meet average daily demand; it does not account for seasonal shortfall (winter days produce significantly less than the annual average PSH), roof shading, orientation penalty, or the difference between grid-tied net-metering and off-grid battery storage. For year-round off-grid EV charging, use winter PSH and add 15 to 30% headroom. Verify the array output against your inverter's maximum input and your roof's available area.
Reviewed and maintained by Rick Oosterling, who builds and wires 12 V, solar and EV systems hands-on. Last reviewed: June 2026. This is a planning aid; confirm your final array design, inverter sizing and installation against your local grid-connection rules and the equipment manufacturer's instructions.