SOLAR
How to Estimate Solar EV Charging
Contractor method for sizing the solar capacity to charge an electric vehicle.
Solar EV charging estimates fail on the efficiency and the sun hours. The daily miles are easy math; the vehicle's efficiency and the panel production determine how many panels you need.
THE SHORT ANSWER
How do you estimate solar EV charging?
Multiply daily miles by efficiency for the daily kWh, then divide by each panel's daily production. 12 kWh/day ÷ 1.44 kWh/panel needs about 9 panels.
Estimate the daily energy
Multiply the daily miles by the EV's efficiency. An EV running ~0.30 kWh/mi over 40 mi/day uses ~12 kWh/day.
- Confirm the daily miles
- Check the EV efficiency
- Note the battery size
- Count the charging sessions
Compute the panel production
Each 400 W panel produces its wattage × sun hours × 0.8. At 4.5 sun hours, a panel makes ~1.44 kWh/day.
Divide to find the panels
Divide the daily EV energy by the panel production. Use the Solar EV Charging Calculator, then round up and add one for cloudy days.
Note the charger
A charger or reinforced outlet is required above a certain power. Solar EV estimates are preliminary — confirm with a certified installer.