Charging your Electric Vehicle (EV) with solar panels just makes sense

As electric vehicles (EVs) have become more widely available and accessible, so have options for charging those vehicles. Nearly every automaker offers an EV option, prices have dropped significantly, and there’s sustained growth in the renewable energy and electric transportation industries—it's clear that charging EVs with solar panels has never been easier.

According to the International Energy Agency’s (IEA) Global EV Outlook 2023 report, electric vehicle sales hit a record high of 10 million in 2022 and now represent nearly one-fifth of the world’s auto market. Compared to gas-powered vehicles, EVs help drivers reduce their carbon footprint and save money on fuel. Most EV drivers prefer to charge their vehicles at home or work and only rely on public chargers when traveling.

Indeed, there are important questions to consider: How much energy does an EV need to fully charge? Is there an efficient and cost-effective way to charge your electric vehicle?

This blog post will provide answers that can help you decide if it’s time to make the switch and charge your EV with solar panels.

How much electricity does EV charging use and how to calculate it

The Environmental Protection Agency (EPA) measures the charging efficiency of EVs in kilowatt-hours (kWh) of electricity per 100 miles. Although there’s a wide range across makes and models, the average EV charging efficiency in the U.S. is approximately 31 kWh/100 miles. Every mile driven requires 0.31 kWh of electricity.

Drivers have two options for at-home charging: A Level 1 EV charger, also known as a trickle charger, or a Level 2 EV charging station.

For average drivers, trickle charging is often enough to “top off” a battery when the vehicle is plugged in overnight. If your time is limited, a Level 2 electric vehicle supply equipment (EVSE) uses more electricity, resulting in faster charging speeds.

Since a significant percentage of grid-based electricity is derived from fossil fuels, you may still be relying on fossil fuel to power your EV. However, adding a solar PV system to your property allows you to charge your EV using cleaner and more affordable power than utility-supplied energy.

Can you combine solar panels and an EV charger for solar EV charging?

An EV charger can work with solar panels, too. As illustrated, most solar EV charging setups include rooftop solar modules, microinverters, a current transformer (CT) meter, and a Level 2 EV charger.

Enphase’s industry-leading solar systems and EV chargers make it easy to design your own integrated solar EV charging station. Once you install the hardware, you can monitor and control the energy throughout the Enphase Home Energy System using the Enphase App—ensuring your EV uses primarily, or exclusively, solar power when charging.

Powering your EV with solar energy

Electric vehicles consume an average of 4,666 kWh of electricity annually. Each kW of solar capacity you install can be expected to produce an average of approximately 4 kWh/day or 1,500 kWh/year of electricity in the U.S. To charge a typical EV, you’d need to install about 3.1 kW—or 4,666 kWh/1,500 kWh—of solar capacity.

You may need an additional eight to 12 modules to charge an EV with solar, depending on your solar panels’ wattage capacity. Use our free solar calculator to see how much solar you need to charge your EV and power your home. You can provide the calculator with information on your driving habits, vehicle make and model, and charger type to get a more accurate calculation.

The best method of charging your EV

Along with installing an EV charging station at home, you'll need to decide how to power the charger. Grid-powered electricity is one option, but it’s often expensive and not environmentally friendly. Solar power, on the other hand, is the most climate-friendly and affordable way to charge your EV. 

It costs just $415 annually to charge a vehicle using solar power at home. In contrast, grid power costs an average of $662 and public EV charging stations cost an average of $1,058. The annual cost of gasoline is $1,260 on average, meaning solar charging can help you save more than $800 per year.

A solar system with battery storage offers more independence from the grid. Battery storage provides access to stored electrical power during blackouts and can provide greater control over how and when you charge your EV. A bi-directional EV charger can transform your EV into a power source for your property through vehicle-to-home (V2H) charging and vehicle-to-grid (V2G) charging capabilities.

Finding the perfect charging setup for your EV is not as difficult as you might think—and Enphase is here to help.

Start your solar journey with Enphase

Key Takeaways:

• In 2022, a record number of EVs were sold, and sales are expected to increase by 35% in 2023. 

• An EV helps decrease your carbon footprint and costs less to drive than gas-powered vehicles.

• The average EV in the U.S. uses about 4,666 kWh per year, and driving 100 miles typically requires 0.31 kWh of electricity.

• Charging your EV at home with solar power costs less than using a public charger or grid power at home.

• You may need to add up to 12 additional panels at your home to charge an EV with solar.

FAQs

1. Can I charge my EV with solar panels?
Yes. It is possible to charge an EV with solar panels, but you need the right equipment. As part of an integrated Enphase Home Energy System, Enphase EV chargers can give you direct access to the clean electricity produced on your property to power your electric vehicles’ batteries.

2. How many solar panels do I need to charge my electric vehicle?
The number of solar panels you need to charge an EV depends on the charging speeds and battery capacity. A typical EV will need the amount of electricity produced by eight to 12 solar panels annually. 

3. What is the best time to charge an EV with solar panels?
The best time to charge an EV with solar panels is during peak sunlight hours, between the late morning and mid-afternoon. During peak sunlight hours, solar panels can perform at their highest efficiencies, producing more solar power to charge your EV. 

4. Do I need a special EV charger for solar panel charging?

Yes. Although EV chargers and solar panels work well together, not all EVs can be charged by solar power directly. When used with an Enphase Home Solar Energy System, an Enphase EV Charger delivers pure solar EV charging in Self Consumption Mode, sending the excess clean energy generated by your panels into your EV battery.

5. Are there any government incentives or tax credits available for using solar panels to charge an EV?
Yes. There are many federal and local government incentives, tax credits, and programs designed to reduce the overall investment costs of both solar panels and electric vehicle supply equipment (EVSE). Although incentives specifically for solar EV charging are rare, both solar incentives and EV charging incentives may be available in your area. 

6. How long does it take to charge an EV using solar panels? 
The intensity of the electricity and the EV’s battery capacity determine how long it takes to charge an EV with solar panels. If you charge an empty EV battery with a capacity of 40 kWh using 5kW of solar, it would take about eight hours to fully charge the battery (40 kWh/5 kW). 

7. How does an EV charger work with a home battery system?
If connected to a home battery system, you can charge your EV directly with the energy stored in a backup electricity reserve. This allows you to charge your EV when grid power isn’t available, is too expensive, or when new solar power isn’t available. With the Enphase App, you can control the source of electricity for your charger, whether it’s the battery, solar panels, or the energy grid.

8. Do I also need a battery to charge an EV with solar?
No. You do not need a battery to charge an EV with a grid-tied solar system. However, a battery allows you to charge your EV with clean power, even after the sun has set. If you need more help, contact our EVSE specialists.