Electric vehicles (EVs) are becoming increasingly popular in the U.S. and around the world for their environmental and performance benefits. Meanwhile, manufacturers are launching plug-in EV models across their fleets.

Whether you own an EV or are interested in purchasing one, there’s a fair chance you’ll also be in the market for a home charging port for your EV battery.

There are fewer public charging stations on the road than traditional gas stations. As such, it’s reasonable to want to buy a port that’s readily available for use at your home. It’s convenient and, in some cases, necessary.

Most home charging ports source energy from the electric grid. However, it’s possible — and much more sustainable — to source energy from solar panels instead. Attaching solar panels to your EV charging port at home saves you significant money because some EVs require a lot of electricity to fully charge.

Here, we’ll look at how different EV battery types (and EV battery sizes), as well as your home solar panel system efficiency, determine the number of panels you’ll need to charge your EV.

WHAT SIZE IS YOUR EV BATTERY?

You need to determine your EV battery’s capacity before you can see how much electricity you need to fully charge it. EV battery capacities are measured in kilowatt-hours (kWh) and range from 17.6 kWh to 200 kWh.

As of 2021, these are the five EVs with the highest battery capacities:

1. GMC Hummer EV: 200-kWh battery with 329 to 350 miles of range
2. Rivian R1T and R1S: 135-kWh battery with 314 miles of range for the R1T and 316 miles of range for the R1S
3. Lucid Air: 118-kWh battery with 520 miles of range
4. Mercedes-Benz EQS: 115-kWh battery with 350 miles of range
5. Tesla Model S and Model X: 100-kWh battery with 387 to 520 miles of range for the Model S and 335 to 371 miles of range for the Model X

Ask your dealership for the most up-to-date information if you’re unsure how to determine your current EV battery’s capacity or that of one you want to purchase. Once you know the EV battery’s capacity, you can calculate the amount of electricity you need to charge it.

Additionally, your solar panels’ size and efficiency determine the number of panels you need to generate enough energy for your EV battery.

DOES SOLAR PANEL EFFICIENCY MATTER?

The number of solar panels you need to power your EV as well as your home depends on several factors:

• The manufacturer and type of solar panels you choose
• How much sunlight is in your area
• Your home and driving energy usage

Some solar panels are more efficient than others, so you won’t need as many to meet your energy needs. SunPower solar panels are the best choice on the market for efficiency — the company offers multiple monocrystalline panel options with an efficiency of up to 22.80%.

The top companies for the best residential solar panels include the following:

• SunPower
• LG Solar
• REC Group
• Panasonic
• Silfab
• Q Cells
• Canadian Solar
• JinkoSolar
• Trina Solar

HOW MANY SOLAR PANELS DO YOU NEED TO CHARGE YOUR EV?

A typical solar panel is 250 watts and generates about 30 kWh to 42.5 kWh of energy monthly. On the lower end, you’ll make about 1 kWh of energy daily. This means you’d need around 75 solar panels to charge a Tesla Model S to 100% every day if it starts at 0%.

Your EV likely won’t be as low as 0% every time you charge it, so that’s a conservative estimate.

With a high-efficiency SunPower solar panel system, you get 9.1 KW for an average cost of $38k. These panels are rated up to 420 watts per panel, allowing you to generate up to 54 kWh of energy monthly or 1.8 kWh daily. That means you’d need only 42 panels.

The average travel distance for a driver is 39 miles per day, which equals about 12 kWh of electricity. As such, you’ll need 12 standard-efficiency solar panels for your charging needs.

However, if you drive less than the average 39 miles per day and own more efficient solar panels, you’ll need fewer than 12 panels for your EV charging needs. Investing in high-quality, efficient solar panels is better in the long run.

Additionally, the average U.S. home requires between 19 and 34 solar panels to fully cover its electric bills. You should expect this number of panels to increase when you add an EV to charge.