How to charge your EV with home solar panels

Charging your EV from your own panels is the most profitable combo of the energy transition: every kWh you put in the car battery saves you $0.25-0.40. The key question is: how many panels do you need given your daily miles?

How much energy your car uses

Modern EVs use 14-22 kWh per 100 km (~24-37 kWh per 100 mi). Let's use 17 kWh/100 km as average. If you drive 25 mi/day (US average), you need ~6.8 kWh/day.

• Tesla Model 3: 14-16 kWh/100 km (24-26 kWh/100 mi)
• Chevy Bolt: 16-18 kWh/100 km
• VW ID.4: 17-20 kWh/100 km
• Large EV SUVs (Rivian R1S, Hummer EV): 25-35 kWh/100 km

How many panels

6,800 Wh ÷ 4.5 PSH × 1.3 = 1,964 W of panels just for the car. Combined with a typical 30 kWh/day household, a family with one EV needs ~5-6 kW DC, which is 12-14 × 450 W panels.

Wallbox: pure solar, hybrid or off-peak

Modern wallboxes (Wallbox Pulsar, Zappi, Tesla Wall Connector) detect surplus solar in real time and modulate the car's charge to use only what you produce. Three modes:

• Pure solar (ECO+): charger only turns on when ≥1.4 kW surplus. Slow but free.
• Hybrid (FAST): blends solar + grid for steady fast charging.
• Off-peak: uses cheap night rates, then offsets with daytime export.

Indicative full kit cost

6 kW solar install + 7 kW smart wallbox: $11,000-16,000 (before incentives). Payback: 5-7 years if you drive more than 7,500 mi/year. EV ownership is the single biggest accelerator of solar ROI.

If you'll charge the EV alongside AC and a fridge, check the global calc in how many panels for a home.