Guide
Solar EV Charging at Home: When the Math Works
Decide when solar panels make EV charging cheaper than grid-only charging.
Solar charging sounds simple: put panels on the roof, plug in the car, drive on sunlight. The real economics depend on when the car is parked, whether exported solar earns retail credit, and how much extra system size the EV adds.
Size Your Solar + EV Charging System
Solar Panel Sizing
Enter Your Details
Fill in the form and click Calculate to see results.
EV Charging Calculator
Enter Your Details
Fill in the form and click Calculate to see results.
Estimate the extra solar load
Solar charging sounds simple: put panels on the roof, plug in the car, drive on sunlight. The real economics depend on when the car is parked, whether exported solar earns retail credit, and how much extra system size the EV adds.
Match charging time to solar production
Key assumptions: EV energy need = annual miles divided by vehicle miles per kWh. Solar production should use location, tilt, orientation, shading, and system-loss assumptions. Battery need depends on whether the vehicle is home during solar production hours.
Compare solar charging with off-peak grid rates
Important caveats: Do not call solar charging zero-cost without acknowledging upfront cost. Separate solar-only EV offset from whole-home solar ROI.
Frequently Asked Questions
Start with annual miles and EV efficiency. A driver using 3,000-4,000 kWh per year for the car may need a small 2-4 kW solar addition depending on local sun and losses.
Use EV Charging Cost Calculator to turn these assumptions into a quick estimate.