How to Use Solar Panels to Charge An Electric Car 

December 26, 2022  |  Solar Energy

Electric vehicles seem to be everywhere these days! According to Bloomberg, we’ve now entered the “tipping point” for mass adoption of EVs. Still, the number of public charging stations lags behind, leaving many EV owners inconvenienced when they need to charge their cars. An at-home charger would seem to be the best solution, but high energy costs can feel prohibitive – if you’re paying an electric bill, of course. Fortunately, EV owners who’ve made the move to solar energy have no such problem, and can use their solar panels to charge an electric car! 

Charging EVs with solar at home is, of course, different from charging at designated stations. At home, the solar panels harvest energy from the sun and convert it to electricity. At charging stations, you charge with electric energy from the grid – unless these stations are also powered by solar.

Wondering how it works? Read on!

EV Solar Charging Glossary

Before we dive into the article, here are a few terms to familiarize yourself with:

KWH – Kilowatt Hours is the measurement of a single unit of electricity. 1 kW (or 1,000 watts) is a measure of energy (or ‘potential’ power), and power is a measure of energy x time, or kilowatt*hour (kWh). KWH is the amount of energy an appliance consumes in a single hour. 

In EV charging terms, kWh refers to the number of kW needed to fully charge an EV in one hour (note: most residential EV chargers are Level 2 and take about 4-5 hours to charge an EV).

Energy Storage System – An integrated solar energy storage system consisting of a battery, system controller, battery inverter, and interface.

Range – The maximum distance a certain amount of electric charge can power your car.

Inverter – An electric device that converts direct current (DC) into Alternating Current (AC) that home appliances can use.

Surge Controller – A device that controls the amount of electricity fed into your appliances. It protects from abnormal voltage spikes that may be caused by excess energy generation or external factors such as lightning. 

How to Install Solar Panels for EV Charging

You can install solar panels on the roof of your house or a separate structure at home for EV charging. Alongside the solar panels, you should install a power inverter, and, if necessary, solar batteries, depending on how much power you want to harvest. All these items make up for a complete solar power system.

Hire a Qualified Solar Professional to Install Your Solar Panels

Day One Solar Solar Company in Santa Cruz CA

Installing solar panels for EV charging is a process best done by skilled professionals. A solar expert should evaluate your electrical system before designing a compatible solar system. This will include inspecting your roof to determine where it’s structurally sound to support the solar panels. The solar expert will calculate how much solar energy you need and give a quote. With that in mind, it’s best to hire a trusted company or contractor for the task.

Here is a simple formula to determine system size: 

Total electrical usage for the past 12 months (in kWh) / 365 days to get the average daily usage (x). Then, divide x by 5.6 (average sun hours per day at our latitude), then divide by .8 (DC loses 20% of energy when inverted to AC) to get system size in kW.

(x/5.6)*0.8= total system size

The harvested solar energy is stored in batteries. There are various solar battery manufacturers such as LG, Enphase, SolarEdge, and Sonnen. With a robust solar battery, you can store the excess energy from your solar and use it to power your electric car when panels aren’t producing enough charge at night. 

Solar panels produce energy in direct current (DC). The Solar inverter converts the energy from DC to AC that you can use to charge your electric car or power other home appliances.

How Many Solar Panels Do You Need to Charge an Electric Car?

You need to generate enough solar power to charge an electric car. Cars with a high battery rating, such as Ford Mustang Mach-E, require more solar panels to generate enough electricity than cars with smaller batteries. The amount of solar panels needed to charge an electric car depends on the daily miles you drive and the system size. The solar installation expert should evaluate your yearly usage and advice on the system size you need for your EV.

How Long Does It Take to Charge Electric Car Using Solar?

The amount of time it takes to charge an electric car depends on the type of solar panels you have, the type of charger, and the amount of sunlight. When using solar energy, charging a car to full charge takes about 4-8 hours. When using solar, you can only charge efficiently during the day. At night, the solar panels do not generate any power. 

During the day, you are highly likely to be away from home. This is where Net Energy Metering comes in your favor. You can feed the excess energy during peak rate periods (7 am to 4pm) to the electricity and earn credits. You can then charge your EV during off-peak hours (12 am to 7 pm), at highly discounted rates.

Benefits of Using Solar Panels for EV Charging

Charging electric cars with solar panels comes with lots of advantages. These include:


While the initial cost of installing solar panels for electric car charging can be high, it’s highly profitable in the long run. Once you’ve installed the panels, you can charge without any hiccups. A solar panel has a lifespan of about 25 years. This means that once you install solar panels today for EV charging, you’ll have at least 2 decades of free charge. 

All Year Round Energy

Provided your area has at least 3 hours of sunlight every day – sorry, Arctic Circle readers! – you are assured of a constant electricity supply all year round. All you need is to have the right amount of solar panels that can generate enough electricity to charge your EV.

Eco-Friendly Solution

Solar energy is the most eco-friendly means of energy. With solar panels, you are using green energy directly from the sun. Grid electricity on its own is not sustainable, as some of it comes from fossil fuels and coal. With solar panels, you don’t emit any greenhouse gasses and play your part in slowing the effects of climate change. 

Saves Time

Have you ever pulled over to charge your electric car at a public charging point, only to find other cars lined up? That can be very frustrating, especially if you don’t have enough power to take you to the next charging station. 

With your solar charging station at home, you can charge your car at your convenience and save lots of hours. 

Why Choose Day One Solar?

Day One Solar provides comprehensive solar power solutions for homeowners and businesses in Santa Cruz. At Day One Solar, we can help you install a robust EV charging system at home powered by solar. Our technical experts will assess your energy needs and advise you on the best solar devices to install for hassle-free electric car charging at home.

Contact us today for a consultation, and we’ll be happy to help you!