How Many Solar Panels to Charge an EV?
Short answer: for a driver covering around 10,000–13,000 miles a year in an efficient-to-average EV, it takes roughly 5–8 additional 400 W panels in a strong Los Angeles solar location. But that’s a planning scenario, not a universal number — the real figure depends on your car’s efficiency, how far you drive, and how much sun your roof gets. The calculator below lets you plug in your own numbers.
Get a free estimate
- A typical LA driver needs roughly 5–8 extra 400 W panels for the car — an example, not a fixed rule.
- The math: annual miles × EPA kWh/100mi ÷ 100 = yearly charging energy.
- EPA kWh/100mi already includes normal charging losses — don’t add a separate loss factor.
- Efficient EVs use far less energy than trucks/large SUVs, so the panel count swings a lot.
The simple math
Charging an EV is just added electricity use, so you size solar for it the same way you size solar for anything: figure out the yearly kilowatt-hours, then work out how much solar produces that in your location.
Step 1. Yearly car energy = annual miles × EPA kWh/100mi ÷ 100.
Step 2. Solar size = yearly car energy ÷ annual production per kW (about 1,700 kWh/kW in LA).
Step 3. Panels = solar size ÷ panel wattage (e.g. 0.4 kW for a 400 W panel).
For example: 12,000 miles × 35 kWh/100mi ÷ 100 = 4,200 kWh/year. Divided by 1,700 ≈ 2.5 kW, or about 6–7 panels. Swap in an efficient EV and it drops; swap in a big truck and it climbs.
Estimate the panels for your car
Pick a vehicle efficiency (or enter your car’s EPA rating), set your yearly miles, and see roughly how much extra solar it takes in a strong LA solar location. This is a planning estimate, not a system design.
EV solar estimator
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.
Why there’s no single answer
Two things vary a lot between households, and both feed straight into the panel count.
Your car’s efficiency
EPA energy use ranges from the mid-20s to well over 45 kWh per 100 miles. An efficient sedan and a full-size electric truck can differ by nearly 2× — look up your exact model’s EPA rating rather than assuming an average.
How much you drive
Recent federal data puts average driving near 10,800 miles a year per vehicle, but real households range widely. We use 12,000 as an example, not a stand-in for your driving — use your own odometer trend.
Sources: EPA — car vs. EV energy use · FHWA — average annual miles.
Don’t double-count charging losses
Some estimates take the EPA kWh/100mi number and then add another 10–15% for “charging inefficiency.” That’s double-counting: the EPA rating is measured at the wall and already includes normal Level 2 charging losses (EPA — EV range & energy testing). Use it as-is.
Does an EV mean I need a whole new solar system?
Not necessarily — but adding an EV is a real jump in usage, so it’s worth sizing for. How much it adds depends entirely on your driving and your car; for many California households an EV is a substantial share of total home electricity, not a rounding error. If you already have solar, this is often a reason to add panels (and possibly a battery) rather than start over. See can solar power a whole house and adding a battery to existing solar.
The LA angle
Los Angeles is close to the best case for this math: lots of sun means each kilowatt of solar produces more, so the panel count for a given car is lower here than in cloudier regions. Pair that with charging in the middle of the day when your panels are producing, and you get the most out of every panel. Confirm your roof’s real production potential with NREL PVWatts before finalizing size.
Sources & methodology
Primary 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. The calculator uses EPA energy-consumption ratings (kWh per 100 miles, which already include normal charging losses), a user-chosen annual mileage, and a Los Angeles solar-production assumption of roughly 1,700 kWh per kW per year (confirm your address with NREL PVWatts). Results are planning estimates, not a system design.
Frequently asked
How many solar panels does it take to charge an electric car?
For a driver covering about 10,000–13,000 miles a year in an efficient-to-average EV, roughly 5–8 additional 400 W panels in a sunny location like Los Angeles. It’s an example, not a fixed rule — the real number depends on your car’s efficiency, your mileage and your roof’s sun exposure. The calculator on this page estimates it from your own inputs.
How do I calculate the solar needed for my EV?
Multiply your annual miles by your car’s EPA kWh/100mi, then divide by 100 to get yearly charging energy. Divide that by your location’s annual production per kW (about 1,700 kWh/kW in LA) to get the solar size, then divide by panel wattage. Example: 12,000 mi × 35 ÷ 100 = 4,200 kWh → ≈2.5 kW → about 6–7 panels.
Do I need to add extra for charging losses?
No. The EPA’s kWh-per-100-miles rating is measured at the wall outlet and already includes normal Level 2 charging losses. Adding another 10–15% on top would double-count. Use the EPA number directly in the math.
How much does an EV increase my electricity use?
It depends heavily on your car and mileage. As a rough figure, 12,000 miles a year at 35 kWh/100mi is about 4,200 kWh — which for many California homes is a meaningful share of total annual electricity, not a minor add-on. Check your own driving and your car’s efficiency rather than assuming a percentage.
Can I charge my EV directly from solar during the day?
Yes — and in Los Angeles that’s often the smartest approach. Charging in the middle of the day uses your solar as it’s produced, which is especially valuable under NEM 3.0, where exporting midday power earns a lower credit. A battery or a scheduled home charger can help line up charging with your solar production.
Related reading
Charge your car on your own sunshine
Get solar sized for your EV, your driving and your LA roof — with day-charging and storage options — from a licensed local installer.
Get a free estimatePrepared by Cali Energy, August 2026. This article is for general educational purposes only and is not legal, tax, financial, engineering, or utility advice. Rates, incentives, codes, permit requirements, equipment specifications, prices, and program terms may change; figures and timelines are estimates, not guarantees. Confirm current requirements with the applicable utility, AHJ, program administrator, manufacturer, or a licensed professional. See our Content Disclaimer. Cali Energy · 19201 Parthenia St Unit E, Northridge, CA 91324 · CSLB #1032379 (B, C-10, C-39)