What Kind of Solar System Do You Need to Charge an EV?

Pairing solar panels with an electric vehicle (EV) is one of the most effective ways to cut fuel costs and lower your carbon footprint. But designing a system that works well for both your home and your car takes more than just matching panel output to mileage—it also requires considering energy losses, inverter selection, and smart system sizing.

🚗 How Much Energy Does an EV Really Use?

Most EVs consume between 25–35 kWh per 100 miles. For the average U.S. driver (~12,000 miles/year), that equals about 3,000–4,000 kWh per year.

But that’s the battery demand—not what your solar panels have to produce. Why? Because every time electricity moves through the system, there are losses.

⚡ Accounting for Energy Conversion Losses

Solar panels generate DC electricity, but most home solar systems convert it to AC for your appliances and grid. Your EV battery, however, stores DC power, so the cycle is:

☀️ Solar DC → Inverter (DC→AC) → EV Charger (AC→DC) → EV Battery

Each step isn’t 100% efficient:

Inverter efficiency: ~95–98%
Level 2 EV charger + onboard vehicle charger efficiency: ~90–95%

Put together, you lose about 10–15% of the energy in conversions.

👉 That means if your EV battery needs 3,600 kWh/year, your solar system really has to generate closer to 4,000–4,200 kWh/year just for charging.

🔌 Inverter Options & Handling EV Charging When Solar or Batteries Fall Short

Choosing the right inverter is critical for EV charging. Beyond efficiency, you’ll want to know how your inverter handles situations when solar and batteries can’t meet demand.

EG4 Inverters (12kPV, 18kPV, 6000XP)

Hybrid operation: Grid-tied, off-grid, or hybrid, seamlessly blending solar, battery, and grid input.
Grid bypass: If EV charging demand exceeds inverter output, the grid steps in automatically.
AC priority scheduling: Models like the 6000XP let you set “AC first” modes—using grid power during set hours.
Near-zero transfer time: Fast switching (<20ms) keeps charging consistent.

✅ Real-world insight: Some users run EG4 inverters without batteries, charging EVs directly from solar with grid assist as backup.

Sol-Ark Inverters

Strong grid passthrough: Handles heavy loads like EVs by letting the grid cover excess demand.
Hybrid flexibility: Integrates solar, battery, and grid in one system—well-suited to EV charging.

SRNE Hybrid Inverters

Smart power flow: Allocates power between solar, home loads, battery storage, and grid.
Dynamic grid support: Draws from the grid when solar and batteries can’t keep up.
Flexible modes: Off-grid, backup, and grid-assist settings optimize EV charging.

🌞 Why You Should Consider Over-Paneling

“Over-paneling” means installing more solar capacity than your baseline home usage requires. For EV owners, it’s often essential:

EV charging can add 25–50% more electricity use to your household.
Conversion losses mean you’ll need 10–15% extra generation.
Seasonal variation, cloudy weather, and panel degradation reduce output.

👉 Rule of thumb: Add 25–30% more capacity than your estimated EV demand. Planning for a second EV? Oversize now—it’s cheaper upfront than expanding later.

📊 Example: Sizing a Solar + EV System

Driving: 12,000 miles/year
EV efficiency: 30 kWh/100 miles
Battery demand: 3,600 kWh/year
With conversion losses: ~4,100 kWh/year
Solar production factor: 1 kW system = 1,400 kWh/year (sunny climate like California)
Required system size just for EV: ~3 kW
With over-paneling: ~3.5–4 kW recommended

If your home already needs a 6 kW system, adding an EV might push you toward an 8–9 kW installation.

✅ Conclusion

Yes—you can absolutely charge your EV with solar. But don’t just match mileage to panel output. To build a resilient, future-proof system, you need to:

Account for conversion losses (add 10–15%).
Select the right inverter (EG4, Sol-Ark, and SRNE all offer hybrid systems that blend solar, battery, and grid).
Over-panel your system to cover EV demand, seasonal variation, and panel degradation.

With the right design, you can drive thousands of miles each year powered entirely by the sun—while knowing the grid is there to fill in the gaps when needed.