[EV Series] Part 2:

How many panels do I need to solar power my EV? 

This is a question we get all the time when speaking with potential solar customers or EV enthusiasts who want to power their EV with the sun. . Because hours of sunlight can vary depending on where you live, that will also influence the number of panels needed to solar power your EV. We are a Seattle-based Solar Contractor, so this blog post will focus on Western WA.

OK, now that we have that clarification out of the way… here’s the answer. It depends on the EV! Every EV will have a battery with a certain kWh capacity, and every EV will have an estimated range per charge, estimated by the EPA. We find that the best practice is to assume you will get 80%-90% of that range under real world driving conditions and depending on how much of a lead foot you have. From there, you can use the annual miles you plan to drive and divide that by how many miles you will get from each charge to determine your kWh demand for driving on solar. Don’t worry, we have a few examples for you later in this post.

With the above parameters, a residential solar design can include the additional number of panels needed to cover your annual EV charging needs, even if you don’t yet own the vehicle! It is more cost effective to install the panels you will need in one installation phase vs. splitting it over time, due to permits, filing paperwork with the utility, crew mobilization and more. Let your solar design consultant know you are interested in solar powering your EV and they will help you size your solar accordingly.

So, let’s try a few examples!

For our calculations and for solar sizing, we will assume 90% of EPA range is achieved and 12,000 miles per year:

Example 1 – 2022 Volkswagen ID.4 Pro 

• Battery Size – 82 kWh, Range – 252 Miles (90% of EPA Range of 280 Miles)
• Charges – 48 per year (12,000 miles / 252 miles per charge)
• Electricity Required – 3,930 kWh (48 Charges * 82 kWh / charge)

Solar Power your Car with 4.2 – 4.8 kW (10 – 12 Solar Panels) 

Example 2 – 2022 Rivian R1T 

• Battery Size – 135 kWh, Range – 283 Miles (90% of EPA Range of 315 Miles)
• Charges – 42 per year (12,000 miles / 283 miles per charge)
• Electricity Required – 5,670 kWh (42 Charges * 135 kWh / charge)

Solar Power your Car with 6.3 – 7.1 kW (15 – 17 Solar Panels) 

Example 3 – 2023 Subaru Solterra EV

And last, but certainly not least, the EV with the best name on the market, the 2023 Subaru Solterra EV! We know the PNW loves their Subies, and we love that Subaru chose to honor our 14 year brand with the naming of the Solterra EV ☀️

• Battery Size – 72.8 kWh, Range – 205 Miles (90% of EPA Range of 228 Miles)
• Charges – 58 per year (12,000 miles / 283 miles per charge)
• Electricity Required – 4,222 kWh (58 Charges * 72.8 kWh / charge)

Solar Power your Car with 4.6 – 5.3 kW (12 – 14 Solar Panels) 

There are many more wonderful electric vehicles on the market and the above examples can be used to calculate the electricity required annually for any EV you select. Our process as solar design consultants is to use your goals with solar and the EV you plan to drive to build a solar and EV charging solution customized to you. Reach out to get the conversation started!

If you are interested in learning more about how solar can power your EV, get a free quote here, email us at [email protected], or call or text 206-462-1103.

Author Bio:

Isaac Chamberlain (he/him) is a Solar Design Consultant at Solterra Solar. He is passionate about solar energy, electric vehicles, and how they can work together to move us toward a sustainable energy system. When he’s not driving his electric car to solar consultations, he cruises the streets of Seattle on his electric motorbike or finds trails to ride on his mountain bike. He also coaches high school ultimate frisbee and enjoys vegetarian burgers and baking sweet treats to share with office mates!