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Panels to charge an EV
Updated August 6, 2026 · based on EPA vehicle efficiency and NREL production data · by Cali Energy
How many solar panels does it take to charge an EV? An efficient car driven 12,000 miles a year uses about 3,360 kWh — roughly 5 extra 400 W panels (a ~2 kW system) in Los Angeles. A big truck or SUV can need about 9. That’s on top of the solar for your home’s existing usage, not instead of it.
✓ Uses EPA kWh-per-100-mile ratings and NREL PVWatts Los Angeles production. See every figure it uses ↓
EPA kWh/100mi already includes normal charging losses — no extra fudge factor needed.
Assumes ~1,700 kWh per kW per year for Los Angeles (confirm your address with NREL PVWatts). Real needs depend on your car, driving, roof and shading.
The rates and figures this calculator usestap to verify
The tool turns your annual miles into charging kWh using an EPA efficiency, then sizes solar to cover it at Los Angeles production. Here is every figure it uses — each table links to its source.
| Efficient car | ~28 |
| Mid-range | ~35 |
| Truck / large SUV | ~48 |
| Panel wattage | 400 W |
| Los Angeles production | ~1,700 kWh per kW-year |
| Charging energy | miles × kWh-per-100 ÷ 100 |
| Added solar (kW DC) | charging kWh ÷ 1,700 |
| Panels | kW ÷ 0.4, rounded up |
EPA kWh-per-100-mile ratings already include normal charging losses, so no extra fudge factor is added. Production is NREL PVWatts modeling for Los Angeles. This sizes only the extra solar for the car — it stacks on top of the array for your home’s existing use. Real needs vary with your exact car, driving, roof and shading.
Example results you can reproduce
Each row assumes 12,000 miles a year in Los Angeles — set the same efficiency and miles above to reproduce it.
| Vehicle (12,000 mi/yr) | Charging energy | Added solar | Panels |
|---|---|---|---|
| Efficient (~28) | ~3,360 kWh | 2.0 kW | 5 |
| Mid-range (~35) | ~4,200 kWh | 2.5 kW | 7 |
| Truck / SUV (~48) | ~5,760 kWh | 3.4 kW | 9 |
How this calculator works
It multiplies your annual miles by the car’s EPA energy use (kWh per 100 miles) to get yearly charging kWh, divides by Los Angeles production of ~1,700 kWh per kW to get the added system size, and divides by 400 W to get panels. EPA ratings are measured at the plug, so they already include charging losses. The result is the solar you’d add specifically for the car, over and above whatever covers the rest of your home.
How to read your result
The big number is the extra 400 W panels to cover the car in an average LA year; beneath it are the annual charging kWh, the added kW, and a typical range (1,500–1,700 kWh/kW-year) showing how the count shifts with your exact sun. Add these panels to your home’s existing solar size — an EV is one of the biggest single loads you can add, which is why it often justifies a larger array or a battery to charge overnight.
What moves the result the most
Two inputs dominate: how far you drive and how efficient the car is. A truck at ~48 kWh/100 mi needs nearly double the panels of an efficient sedan at ~28 for the same miles. Cut either — drive less or pick a more efficient car — and the solar need drops proportionally.
Common questions
What do I need to use this calculator?
Your annual miles and the car’s EPA efficiency in kWh per 100 miles. If you don’t know the rating, pick the closest preset — efficient sedan, mid-range, or truck/SUV.
Where do I find my car’s kWh/100 mi?
On the window sticker’s efficiency rating, or by looking your model up on the EPA’s fueleconomy.gov. Most EVs land between ~25 (efficient sedans) and ~50 (large trucks).
Do I need to add charging losses?
No. EPA kWh-per-100-mile figures are measured from the wall, so the energy lost charging the battery is already included — no extra padding needed.
Can I charge the car purely on solar?
Over a year the panels can generate the kWh your car needs, but the sun and your charging rarely line up hour to hour. Most people charge overnight from the grid and offset it with daytime solar credit, or add a battery.
Does this include my home’s electricity?
No — it’s only the extra solar for the car. Size your home’s usage separately and add these panels on top for a full system.
Why do trucks need so many more panels?
A big pickup’s size and drag mean it uses far more energy per mile — often ~48 kWh/100 mi versus ~28 for an efficient sedan — so covering the same miles takes close to twice the solar.
Sources
- EPA — Comparison: Your Car vs. an Electric Vehicle
- EPA — Fuel Economy and EV Range Testing
- FHWA — Highway Statistics, Average Annual Miles (VM-1)
- NREL — PVWatts Calculator
Estimates only, not a quote. Assumptions, rates, incentives and program rules can change — confirm current details with your utility, the program administrator or a licensed professional.
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