EV Solar Charging Calculator
Find out how many solar panels you need to charge your EV, whether a home battery is worth it, and how much money driving on sunshine saves you every year.
1. Your EV & home
2. Solar system
Typical home: 4-10 kW.
Solar production / year
Panels for your EV
~400 W panels to cover EV + home
Solar share of EV
Yearly savings
Energy balance
Money saved & payback
Worked example: 12,000 km/year EV + 5 kW solar in Southern Europe
5 kW system at 5.5 sun-hours/day, home use 4,000 kWh/yr, EV at 17 kWh/100km, grid at $0.25/kWh:
| Item | Value |
|---|---|
| Solar production / year | ≈ 7,500 kWh |
| EV energy / year | 2,040 kWh |
| Home energy / year | 4,000 kWh |
| Solar covers of EV + home | ≈ 92% |
| Grid bill without solar | $1,510 / year |
| Grid bill with solar | ≈ $125 / year |
| Annual savings | ≈ $1,385 / year |
A 5 kW system costs roughly $8,000-12,000 in Southern Europe — a payback of 6-8 years, then ~15+ years of essentially free driving. Prices and payback vary by region.
Solar + EV tips
- Oversize slightly for the EV. Adding 2-3 kW for a future EV costs little vs buying panels later.
- Charge mid-day when possible. Lunchtime charging from solar surplus is nearly free.
- A battery helps if you charge at night. Store daytime solar, charge after sunset.
- Smart chargers auto-use solar surplus. They switch between solar and grid automatically.
- Claim every incentive. Solar rebates + EV charging credits stack with EV purchase incentives.
How it's calculated
- Solar output ≈ system kW × sun hours × 365 × 0.75 (system losses).
- EV use = km/year × consumption ÷ 100.
- Coverage = solar ÷ (EV + home) × 100, capped at 100%.
- Payback = system cost ÷ (grid bill without − with solar).
- Oversimplified for clarity — orientation, shading and net metering change results.
Pair with the Home Charging calculator for wallbox sizing and the Charging Cost calculator for tariffs.
Frequently asked questions
Can solar panels fully charge an EV?
Yes, if the system is sized right. A typical home uses 4,000-5,000 kWh/year; an EV adds 2,500-3,500 kWh. A 6-8 kW solar system can cover both in sunny regions, letting you drive on pure sunshine most of the year.
How many solar panels do I need to charge an EV?
Roughly 15-25 panels (400 W each). For 30 km/day, you need about 7-10 kWh of solar daily, which means a 4-6 kW array — plus storage if you want to charge at night.
How much money does solar charging save?
At $0.15/kWh grid price, a 12,000 km/year EV saves $350-500/year in electricity with solar, on top of the $400+ the panels save on home usage. Payback is typically 6-10 years depending on your region.
Is it worth adding a home battery with solar and an EV?
Yes if you want to charge overnight or in winter. A 10 kWh battery lets you store daytime solar and charge the EV at night, maximizing self-consumption. It adds $5,000-9,000 but improves energy independence.
Can I charge my EV directly from solar during the day?
Yes — with a smart charger, your EV can automatically use solar surplus first before pulling from the grid. This solar-only charging can cover 50-80% of a typical commute in sunny months.