How Many Solar Panels to Charge a Tesla?

If you own a Tesla or are thinking about buying one, you likely have researched the different ways of charging and are weighing your options. Powering your Tesla with solar panels should be one of them. With solar, your payback period will be quicker and you’ll be driving a cleaner electric vehicle (EV) since the electricity supplied by a home charging station or Tesla Supercharger is powered by fossil fuels. You’ll save money and help the environment, but you’re probably thinking, “how many solar panels to charge a Tesla?” On average it is 5 to 15 solar panels. But, how do you know many you’ll need to charge your Tesla and how much it will cost? We answer these questions down below. 

Can you charge your Tesla with solar?

Yes, you can charge a Tesla and any other EV with solar power. If you want to lower your carbon footprint even further (you are driving with zero emissions already) start juicing up with solar energy.

One of the arguments against electric cars is they power up with fossil fuel supplied by grid power. While this is true, when it comes to the lifetime of an electric car when compared with a traditional car an electric vehicle is much more environmentally friendly due to its zero tailpipe emissions.

If you power up your Tesla battery with solar panels you’ll save money, have a 100% carbon-neutral footprint, and always know your car can be charged at home in the event of a power outage or blackout. 

If you want to power your Tesla with solar make sure to speak with your solar installer to size your system appropriately for the additional load. If you have an existing system, your solar installer can add to your existing solar panel system. 

How do you charge a Tesla with solar?

Do not connect solar panels directly to your Tesla battery. Doing so will not charge your Tesla.  

Here is a list of the items you will need for a Tesla solar charging system:

• Solar panels
• Solar charge controller
• Energy storage system
• Inverter
• EV Charging station

Here are the steps you’ll need to follow to set up a solar charging system for your Tesla:

1. Install solar panels that have been sized for charging your Tesla. We get to how many further in this article.
2. Install an energy storage system to collect solar power for your EV charging station.
3. Connect the solar charge controller. A solar charge controller is connected between solar panels and the solar batteries to regulate the voltage and current and to prevent battery damage from overcharging. It will also only allow power to flow from the solar panels to the batteries. 
4. Connect the inverter. The inverter converts the direct current (DC) energy produced by the solar panels into alternating current (AC), which is the type of energy EV chargers use. 
5. Install an EV charging station. 

While the installation steps do not have to be in this exact order, all the equipment does need to be connected as follows:

SOLAR PANELS  > SOLAR CHARGE CONTROLLER > ENERGY STORAGE SYSTEM (SOLAR BATTERIES) > INVERTER > EV CHARGING STATION

You should not try to install a solar EV charging station by yourself. You need to connect with a trusted energy efficiency solutions company, like WattLogic, that specializes in EV charging and solar technology installations. This way you can ensure everything is sized appropriately and installed properly.

You will need a Tesla Mobile Connector to charge your Tesla with a solar charger. It is a cable with interchangeable adaptors, one of which will be a 240-volt adaptor for your Level 2 EV charger. Plug the Mobile Connector’s adaptor into the power outlet. With your Tesla unlocked, press the button on top of the Mobile Connector handle. The charge port door opens and you can start charging.

How many solar panels do you need to charge a Tesla?

The answer to this question requires gathering some simple information. Since not all regions or Teslas are the same, this answer will depend on several factors:

• The battery size of your Tesla
• How much you drive
• The efficiency of your solar panels 
• Where your home is located 

The battery size of your Tesla will determine how much kilowatt-hours (kWh) of energy you use each time you drive. Here is a chart of battery sizes for the most recent Tesla models:

TESLA BATTERY SIZES

Then, figure out how many miles you drive. According to the Federal Highway Administration (FHA), the average driver travels 14,263 miles per year, which is about 1,189 per month, or about 39.11 per day. 

Next, figure out the range of your Tesla. Again, we provide a chart here of the most current 2022 models to make it easier for you.

TESLA RANGES 

Now figure out the efficiency of your solar panels. Typical home solar panels are rated for 250 to 400 watts. This rating translates to how many watts (W) of electricity your panels should produce per hour. 1,000 W equals 1 kW, so the average would be .25 kW – 0.40 kW. 

To find out how much kWh your solar panel should produce let’s use the Tesla Model S as an example. With a range of 205 miles, 39.11 miles represents about 19.08% of a full battery. The battery is 100 kWh, so the solar array needs to be able to supply 20 kWh. 

You’ll need to convert that to watts.

 20 kWh = 20,000 watts 

Then, you’ll need to figure out how many peak daily sunlight hours you have in your area. The answer will vary depending on where you live. For example, Arizona has the highest number of sunniest days out of any state in the nation. A homeowner there would expect to see much more sunlight than in a state like Washington, which has the highest number of cloudy days in the country. You’ll need to find out the number of daily peak sunlight hours for your area, which can be found with the National Renewable Energy Laboratory’s U.S. Annual Solar Global Horizon Irradiance map. 

For example, let’s say you live in Southern Arizona. The map shows you see about 5.75 daily peak sunlight hours.

To find out the solar power required to charge your Tesla you will divide the energy you need for daily travel (20,000 watts in our example) and divide that by peak daily sunlight hours. 

20,000 watts/ 5.75 peak daily sunlight hours = 3,478 watts of solar energy required daily

Then, to find out how many solar panels you need to charge a Tesla you need to divide the total solar energy requirement by the wattage of your chosen solar panels. For our example, let’s say your solar panels have an efficiency of 300 watts.

3,478 watts energy requirement/300 watts = 11.59 (12) solar panels

How much energy does it take to charge a Tesla?

Electric vehicle fuel efficiency is not listed as miles per gallon (MPG), instead you will see them listed with miles per gallon equivalent (MPGe). MPGe measures the average distance traveled per unit of energy consumed that is equal to one gallon of gasoline. One gallon of gasoline is equal to 36.6 kilowatt-hours (kWh) of electricity. If your Tesla had an efficiency rating of 100 MPGe, it would be able to travel 100 miles on 36.6 kWh. To make it more simple, here is a chart of the current 2022 Tesla models and their MPGe ratings:

FUEL EFFICIENCY

For older models, please go to fueleconomy.gov to find the accurate MPGe for your Tesla.

How do you get a Tesla solar EV charger at your home?

To get an EV charger installed at your home you will need to work with a trusted installer. You should not attempt to do it yourself since it involves electrical work that can be dangerous if you attempt it on your own. Work with an installer, like WattLogic, that has solar system, battery storage, and EV charging experience and licenses. All the technologies have different requirements and should only be installed by professionals that know what they’re doing. 

If you want to talk to a residential solar expert or would like a free consultation on a solar installation for charging your Tesla please connect with us online and let us know when you would like to talk!