Solar + EV Charging: How to Charge Your Car for Free
Pairing a home solar system with a Level 2 EV charger is one of the smartest energy decisions a homeowner can make. When your solar panels generate more electricity than your home uses during the day, that excess energy can charge your EV — effectively bringing your cost per mile to nearly zero.
A complete home energy setup pairs three pieces: rooftop solar, a whole-home battery backup, and a Level 2 EV charger — all working together so the sun can cover a meaningful share of your driving. Here's how the pieces fit, and how to size them.
With a 10kW solar system generating an average of 35–40 kWh per day in Massachusetts, and a Tesla Model Y consuming roughly 3.5 miles per kWh, you can generate enough solar energy to cover 100–140 miles of daily driving — completely free, from the sun.
How Solar EV Charging Works
- Solar panels generate power — typically peak production from 9 AM to 3 PM
- Your home uses what it needs — appliances, HVAC, lighting draw from solar first
- Excess flows to your EV charger — if your Level 2 charger is running, it draws from solar production
- Remaining excess charges your battery — home battery backup stores what's left for evening use
- Any surplus exports to the grid — net metering credits your electricity bill
The key insight: a Level 2 EV charger draws 7–12 kW of power. A typical 8–12 kW solar system produces roughly that amount during peak sun hours. If you charge your car during the day while solar is producing, you're charging with free electricity.
Three Ways to Set Up Solar EV Charging
Option 1 — Solar Only (No Battery)
The simplest setup. Your solar panels connect to a grid-tied inverter, and your Level 2 charger runs on whatever your panels produce plus grid power when solar isn't enough.
- Best for: Homeowners who can charge during daylight hours
- Cost savings: Significant — solar production directly offsets your EV charging cost
- Limitation: No outage protection, no nighttime solar use
Option 2 — Solar + Battery Backup (Recommended)
Add a whole-home battery (like the Franklin aPower 2) to your solar system. Your battery stores excess solar production during the day and releases it at night — including to your EV charger.
- Best for: Homeowners who want maximum savings and outage protection
- Cost savings: Maximum — solar charges battery, battery charges EV at night at $0 cost
- Additional benefit: Whole-home backup power during grid outages
Option 3 — Solar-Integrated Smart Charger
Some Level 2 chargers (like certain Wallbox and Emporia models) have solar integration features that automatically detect your home's solar production and adjust charging speed in real time.
- Best for: Homeowners with solar but no battery who want optimized solar charging
- How it works: The charger monitors your home energy monitor and adjusts amps dynamically
How Much Can You Save?
| Charging Method | Cost per kWh | Annual Cost (13,000 miles) | vs. Gas Car |
|---|---|---|---|
| Solar (direct, daytime) | ~$0.00–0.03 | $0–$100 | Save $1,400–$2,000+ |
| Solar + battery (nighttime) | ~$0.00–0.05 | $0–$170 | Save $1,300–$1,900+ |
| Home grid (off-peak rate) | $0.08–0.15 | $270–$510 | Save $900–$1,600 |
| Home grid (standard rate) | $0.12–0.30 | $410–$1,020 | Save $400–$1,100 |
| Public Level 2 | $0.35–0.50 | $1,190–$1,700 | Minimal or no savings |
| Gas car (28 MPG @ $4.50/gal) | N/A | ~$2,089 | Baseline |
What Size Solar System Do You Need to Charge an EV?
Step 1 — Calculate your EV's annual energy use
Miles per year ÷ your EV's efficiency (miles/kWh) = annual kWh needed. Example: 13,000 miles ÷ 3.8 miles/kWh (Tesla Model Y) = 3,421 kWh/year
Step 2 — Convert to solar panel capacity
In most U.S. locations, 1 kW of solar panels produces roughly 1,200–1,500 kWh per year. To generate 3,421 kWh annually: 3,421 ÷ 1,350 = ~2.5 kW of additional solar capacity — roughly 6–8 additional panels.
Adding 2–3 kW of solar capacity specifically to power your EV typically costs $3,000–$6,000 before incentives — and generates enough electricity to cover 13,000+ miles of annual driving for the 25-year life of the panels.
What EV Charger Works Best with Solar?
- WiFi and smart scheduling: Lets you set charging windows to align with peak solar production hours
- Variable amperage control: Allows you to adjust charging speed based on solar production
- Home energy integration: Some chargers integrate with home energy monitors to automatically adjust based on real-time solar output
Federal Tax Credits for Solar + EV Charging
- Solar Investment Tax Credit (ITC): The 30% federal solar ITC expired December 31, 2025 and does not apply to systems placed in service in 2026. State and utility incentives may still apply.
- EV Charger Tax Credit: Up to 30% of charger and installation costs, capped at $1,000 for residential installations (Form 8911) — but only through June 30, 2026, and only in eligible census tracts.
- State and utility rebates: Many states layer additional incentives on top of federal credits.
See our complete guide to EV charger tax credits for current eligibility details.
Ready to Find the Right Charger for Your Solar Setup?
Use our Build Your System guide to get a personalized EV charger recommendation — including solar-compatible models.
Build Your System →Frequently Asked Questions
Can I charge my EV directly from solar panels?
Yes — when your solar panels are producing more electricity than your home is consuming, the excess automatically flows to your Level 2 EV charger. No special equipment needed with a standard grid-tied solar system.
Do I need a battery to charge my EV from solar?
No — you can charge from solar without a battery by scheduling charging during daylight hours. A battery allows you to store solar energy for nighttime charging and adds whole-home outage protection.
Will solar panels produce enough electricity to charge my EV every day?
In most U.S. locations, a properly sized solar system generates enough excess energy to cover typical daily driving (30–50 miles) during the majority of the year. Winter months will require some supplemental grid power.
What happens to my EV charging during a power outage if I have solar and a battery?
With a whole-home battery backup system like the Franklin aPower 2, your home — including your EV charger — continues operating normally during a grid outage.
Is there a special EV charger I need for solar?
Any Level 2 charger works with a solar system. For maximum solar optimization, look for chargers with smart scheduling or solar-aware charging modes. See our Level 2 EV Charger collection for solar-compatible options.