EV + Rooftop Solar Calculator
Size a rooftop solar system to power your EV. Calculates kWp needed, panels required, self-sufficiency %, annual savings, and payback period with PM Surya Ghar subsidy.
How this works
Required kWp = EV annual kWh / (peak sun hours × 365 × system efficiency). Payback = net cost / (annual generation × tariff)
Methodology
Solar generation: kWh/yr = kWp × peak sun hours/day × 365 × 0.80 (system efficiency). PM Surya Ghar subsidy: ₹78,000 for ≤3 kWp, ₹98,000 for 3–10 kWp (MNRE 2024). Payback = net system cost / annual savings. Seasonal generation uses sinusoidal irradiance model ±15% around annual mean.
Calculator Inputs
Solar irradiance (peak sun hours) varies significantly across India. Rajasthan gets the most sun.
2-Wheeler: ~25 Wh/km · Car: ~140 Wh/km · SUV: ~200 Wh/km
Each 400W panel needs ~1.9 m². A 20 m² rooftop fits ~10 panels (4 kWp)
⚙ Advanced Options
Installed cost including inverter, mounting, wiring. Avg 2024: ₹65,000/kWp
| Panels required | 3 panels (400W each) |
| Annual EV energy demand | 2016 kWh |
| Annual solar generation | 2016 kWh |
| System cost (before subsidy) | ₹86,301 |
| PM Surya Ghar subsidy | ₹78,000 |
| Net system cost | ₹8,301 |
| Annual electricity savings | ₹16,975 |
Summer months (Apr–Jun) generate more solar energy. Monsoon months show reduced generation due to cloud cover.