About
Built for drivers
who think ahead.
VoltSun is a free solar calculator for EV owners. Enter your address, pick your car — we calculate exactly how many panels you need, what you'll save, and when it pays back. No guesswork, no averages. Real satellite data for your exact location.
Why we built this
The question every EV driver asks.
“How many solar panels do I need to charge my car?” It sounds simple — but the answer depends on where you live, what you drive, and how far you go. Generic calculators use national averages that can be off by 30% or more.
VoltSun queries the EU's PVGIS satellite database for your exact GPS coordinates, uses your EV's real consumption profile, and applies local electricity prices. The result is a personalised solar plan — not a rough estimate.
“Generic calculators can be off by 30% or more depending on your location. VoltSun uses satellite data for your exact coordinates.”
Methodology
How the calculation works.
Location → Irradiance
Your address is geocoded to GPS coordinates. We query PVGIS for the monthly solar irradiance at that exact point, averaged over 25 years of satellite measurements. This gives us kWh/m²/day for each month of the year.
EV → Energy demand
Using your vehicle's official consumption (kWh/100 km) and your annual mileage, we calculate exactly how many kWh per year your car needs. This is compared against what a solar system of a given size would produce at your location.
Panels → Plan
We calculate the minimum number of 400W panels to cover your annual EV energy demand. Savings use your country's electricity price. Payback uses a 6,000–8,000 EUR system cost assumption. CO₂ uses your grid's carbon intensity.
Solar data
Why location matters so much.
A solar system in Lisbon generates almost twice as much energy per year as an identical system in Stockholm. Location is the single biggest variable in any solar calculation.
Avg. daily solar irradiance by country (kWh / m² / day)
Source: PVGIS — EU Joint Research Centre. Annual average, horizontal plane.
Data sources
Where the numbers come from.
Not sure what some of these terms mean? Visit our Solar & EV Glossary for plain-English definitions of every concept used in VoltSun.
Solar irradiance data — 25 years of satellite measurements per location
Household electricity prices by country, updated annually
Real-world EV consumption profiles (kWh/100 km) per model
Grid carbon intensity by country for CO₂ savings estimates