October 13, 2022

Charging Your EV With Solar Panels Just Makes Sense

Charging Your EV

Electric vehicles (EVs) are becoming more common on U.S. roadways with each passing year. They are coming down in price, and the recent passage of the Inflation Reduction Act has money dedicated to building the largest charging infrastructure ever seen in this country.

Nearly every significant automobile manufacturer is offering an EV option to their consumers, and consumers are responding positively. In 2021 along, EV sales nearly doubled. Why? Not only can you save money on fuel costs over a traditional gas-powered vehicle, but it can slash your carbon footprint as well. Purchasing an EV starts a virtuous cycle: It costs less to consumers as it helps fight the existential threat of climate change.

Most people, however, are not going to want to use public charging stations except when they’re traveling. Most EV consumers plan to charge their vehicles overnight, so they are ready to be driven during the day. The question, then, is this: What is the energy consumption of electric vehicles? Will I have to redo my entire electrical system to accommodate nightly charging? And, if so, what is the most efficient and cost-effective way to do it?

In the following article, we will explore how much electricity an electric car uses and how to calculate it and you can use a solar-powered EV charging station to power up your vehicle.

How Much Electricity Does an Electric Car Use, and How Do You Calculate It?

The Environmental Protection Agency (EPA) has been hard at work determining how to measure the fuel mileage of electric vehicles. Obviously, the more traditional miles per gallon (mpg) no longer apply because there are no gallons of gasoline involved. As a result, the EPA has decided that cars should be rated on how many kilowatt-hours (kWh) it takes for a car to drive 100 miles.

In general, most electric vehicles use approximately 7,200 watts (i.e., 7.2 kilowatts) of electricity, depending on the model of car and the EV charger you choose to use. And most EV charging stations use between 32 and 40 amps and can be connected to a 240-volt outlet.

The average amount of energy consumption for electric vehicles currently in use in the United States is approximately 31 kWh/100 miles, which breaks down to 0.31 kWh/mile. What makes EVs unique is that they can typically be charged at home—but you can’t just plug your car into the outlet you currently have in your garage and call it a day.

Instead, you will have to invest in an EV charging station, which will provide you enough power to charge your car to 100% overnight. If you drive less than 50 miles a day (which the U.S. Department of Transportation suggests is the average), it will suffice. And in case your home has a solar energy system, using a solar-powered EV charging station at home also creates the least amount of carbon emissions because most grid-based electricity is still derived from fossil fuels.

However, in case your home does not have a solar energy system, once you’ve determined how much electricity you need to use, you can start calculating how big your solar system will need to be to allow you to charge your EV while still powering the rest of your home.

Can Your Solar System Charge Your Electric Car By Powering Your EV Charging Station?

The answer is “absolutely”—assuming you plan accordingly. In fact, you will find significant savings over grid-powered charging. Typically, it costs just $415 annually to charge your vehicle using solar power at your home, while it will cost $662 on grid power and $1,058 on a public EV charger, according to a survey conducted by SolarReviews. In contrast, it can cost up to $1,260 annually to fill a gas car’s tank—and that was before fuel prices skyrocketed in most areas of the country.

Most solar EV charging setups include rooftop solar modules, microinverters and a Level 2 EV charger. Not only is it the most climate friendly way to charge your EV, over the life of a solar system (usually around 25 years), a consumer solar site suggested it could save approximately $16,250 when you charge an EV at home over that time—and that’s if you own only one EV. If you have two or more EVs at a time, you can double or triple that savings.

In most cases, to power a car for an entire year, you will need to produce 4,666 kWh of additional energy. For every kW of solar you install on your roof, you will produce approximately 4 kWh/day or about 1,500 kWh hours/year. To charge a typical EV, therefore, you would need to expand your system by around 3.1 kW, or eight to 12 additional modules over what it would take to power your home.

If you’ve already gone solar, your system may in fact be overproducing as is, and you may not need to expand your system. Pay close attention to your electric bills each month to determine whether you’ll need to expand the system you currently have on your house. Adding a battery (which we discuss here) is another option for charging your EV with your existing system.

The Bottom Line

It’s important to understand the best method for charging them as EVs become more prominent as part of the U.S. transportation mix. Installing an EV charging station at home is the first step, but equally important to decide how you’re going to power that charger.

Depending on where you live, charging your EV from grid-powered electricity can be expensive; consider using solar systems to power your home and EV charger. It’s not as difficult as you might think—and Enphase is here to help you do it. Click here to get started.

Key Takeaways:

  • EV sales nearly doubled last year.

  • Purchasing and EV starts a virtuous cycle: It costs less to consumers as it helps fight the existential threat of climate change.

  • The average amount of energy consumption for electric vehicles currently in use in the United States is approximately 31 kWh/100 miles, which breaks down to 0.31 kWh/mile.

  • Typically, it costs just $415 annually to charge your vehicle using solar power at your home, while it will cost $662 on grid power and $1,058 on a public EV charger.

  • To charge a typical EV you need to add eight to 12 additional modules over what it would take to power your home

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