EV Solar Panel Calculator
Find out how many solar panels it takes to cover a year of EV driving with sunshine.
How this works
First we work out how much electricity your driving needs over a year: miles divided by your EV’s efficiency. Then we estimate how much energy a single solar panel actually delivers in a year — its wattage, times your local peak sun hours, times 365 days, minus typical system losses. Divide one by the other and round up.
Peak sun hours by region
Peak sun hours is roughly how many hours a day your roof gets full-strength sunlight (cloudy and low-angle hours count as fractions). Rough US averages:
- Pacific Northwest, New England: 3.5–4.0
- Midwest, Mid-Atlantic: 4.0–4.5
- South, California: 5.0–5.5
- Arizona, New Mexico, West Texas: 5.5–6.5
System losses
Even good solar setups lose 15–25% of nameplate output between the panels and the meter — inverter inefficiency, wiring resistance, temperature, dust, shading. 25% is a safe default; cleaner installs in mild climates can get away with 15–20%.
Solar panels generate during the day but most EVs charge overnight, so “covering” your driving usually means a net-metering arrangement with your utility — the panels feed the grid by day, you pull from it at night. Without net metering you’d need a home battery to actually run the car on stored sunshine.
Frequently asked
Can solar actually cover an EV's electricity?
Yes — easily, in most US climates. A typical EV uses 3,000–4,000 kWh/year. A modest 8–12-panel system (3.5–5 kW) covers that in the sunnier two-thirds of the country. In low-sun regions you might need 15–18 panels for the same usage.
What are "peak sun hours"?
The equivalent number of hours per day your roof gets full-strength (1,000 W/m²) sunlight. Cloudy hours and low-angle morning/evening light count as fractions. Pacific Northwest gets 3.5–4 PSH; California and South get 5–6; Arizona and New Mexico 5.5–6.5.
Do solar panels actually charge my car directly?
Indirectly. Most setups use grid-tied net metering: panels feed the grid during the day, you pull from the grid at night to charge. Bills net out to roughly zero on the EV electricity. To run directly off solar, you would need a home battery or a daytime charging schedule.
What does an EV-sized solar install actually cost?
In 2026, $2.50–3.50 per watt installed in most US markets. A 4 kW system to cover an EV runs $10,000–14,000 before incentives. The federal residential solar tax credit (currently 30%) drops the net cost to $7,000–10,000. Many states layer additional rebates.
What about cloudy days?
Cloudy days produce 10–25% of nameplate output (modern panels still work in diffuse light). The calculator already builds an average year — sunny days plus cloudy days plus winter — into the peak sun hours figure. No need to compensate further.