Tesla EV in front of solar panels

Charging your Tesla: how many solar panels does it take and how much does it cost?

Following the news of Tesla’s acquisition of U.S. solar installer giant SolarCity, the world has been keeping a close eye on Elon Musk and his two prosperous clean energy ventures. Tesla and SolarCity, electric cars and solar panels – a two-front war waged against grid reliance and energy dependence. In 2019, Musk-owned companies are  both expanding and constricting as two of the tech entrepreneur’s five companies are joining forces around one common goal: eliminating your carbon footprint.


Key Takeaways

  • It’s not only possible to charge your Tesla with solar power, it’s encouraged
  • Homeowners will need to add 10 additional solar panels to charge a Tesla
  • It costs less to charge a Tesla than it does to drive a gasoline vehicle
  • The time it takes to charge a Tesla can vary wildly

Visit the EnergySage Marketplace to compare solar-plus-storage options from your local installers.

Can you charge a Tesla with solar panels?

Many homeowners are wondering if they can charge their Tesla car with solar panels and the answer is you can. An electric vehicle such as a Tesla can serve as battery storage for solar energy. Musk has outlined his newest goal, which he says can be achieved with his one-two punch solution for homeowners seeking alternatives to fossil fuels:

  1. Install solar on your roof to generate electricity by harnessing the power of the sun
  2. Take that photovoltaic energy and use it to charge your Tesla Model S

Was this all possible before the Tesla-SolarCity merger? Of course. A Chevy Volt or Nissan Leaf owner didn’t need Elon Musk’s “master plan” to realize that electric cars can be paired with solar energy. But perhaps Musk’s true innovation was in recognizing that solar panels and electric cars are complementary, not substitute, goods and need to be marketed as such.

You might be able to imagine a world where a tablet and a smartphone are viewed as substitute products, but Steve Jobs successfully reached beyond tech’s power-users and created a need for both to exist in mainstream markets. Similarly, Musk’s latest move targets the layman homeowner, extending beyond clean energy’s early adopters who paired their Leaf or Volt with home solar panels years ago.

Elon Musk with solar panel tesla battery

By bringing two of the world’s leading solutions to emissions reduction under one roof, Tesla can cut operating costs in development and installation, helping homeowners to understand clean energy financing options as a combined cost rather than trying to conceptualize the headache of multiple individual energy investments. In a sense, Tesla is making clean energy simple because it needs to be simple.

With this merger underway and millions considering the prospect of a zero-emissions home, a number of questions are arising in the renewable space. How do you connect solar panels to an electric vehicle? How long will it take for solar panels to charge a car? How many panels will you need to charge your car in the first place? These are some of the issues Musk hopes to solve with one all-encompassing mega brand. Now that Tesla has been unquestionably established as a clean energy behemoth for the future, it’s time to explain what this all means for the carbon-conscious homeowner in a world where going solar or going electric has been merged into a more Musk-approved, illustrious phrase of “going zero” (emissions).

How many kWh does it take to charge a Tesla Model S?

In order to understand how solar cells and Tesla vehicles complement each other in Musk’s vision, we first need to understand how electric cars are charged rather than fueled. And because solar panel systems are sized based on the expected energy usage of a household, a homeowner would need to take into account projected energy needs from his or her Tesla in order to get a solar panel system that can generate enough electricity to meet that combined demand.

The cross-functional metric to use here is kilowatt-hours (kWh), which represents the amount of energy used while kW would refer to available capacity. In order to compare electric vehicles (EVs) to automobiles, the EPA uses the amount of kilowatt-hours required for an EV to travel 100 miles as a miles per gallon equivalent (MPGe).

Efficiency rating by model

Tesla ModelMileage
Model S (2021)101-120 MPGe
Model 3 (2020)113-141 MPGe
Model X (2019)

79-96 MPGe
Model Y (2021)

111-129 MPGe

According to FuelEconomy.gov, the 2020 Tesla Model S Standard Range requires about 31 kWh per every 100 miles, giving it a fuel economy rating of 109 MPGe (combined city and highway). Thus, if the ultimate question is how many kWh it will take to charge your Tesla, it will depend on the distance you plan to travel. A short trip 25 miles each way would require roughly 17 kWh of energy, while the energy needed to run errands around town might only require 2 or 3 kWh. Read our article “How much does it cost to charge a Tesla? EV vs. gas fuel comparison” to see how a gasoline-powered car stacks up next to a Tesla in “refueling” costs.

How long does it take to charge a Tesla?

The time it takes to charge a Tesla depends on a few factors, such as the model and type of connection. For example, homes are equipped with a standard, three-pronged NEMA 5-15 outlet with a 120 volt 15 amp breaker. To charge a Model 3 on this connection, it would take roughly 5 days if the battery had a zero charge initially. On a NEMA 14-30 connection, which is commonly used for electric dryers and is 240 volt, it would take about 16 hours.

How many solar panels does it take to charge a Tesla?

It takes roughly 10 solar panels to charge a Tesla. The question of how long it takes to charge a Tesla with solar energy is dependent on the kW of the system and how many panels are needed to meet higher demand.

Some different factors come into play when it comes to charging an electric vehicle, such as:

  • Solar panel efficiency
  • The EV being charged
  • Location

Now that it’s clear how much energy a Tesla vehicle will require, the next step is to calculate how many solar panels are required to provide that charge and fulfill the Musk doctrine of going completely zero emissions in one fell swoop. Because solar panel electricity production is dependent on a few different factors, we’ll use an example homeowner who already has solar but wants to know how many more panels it will take to supply energy for a Tesla Model S. Let’s call her Barb.

Barb has a 5 kW (5,000 watt) solar system, the average system size for the U.S. residential solar market. She lives in Cleveland, Ohio where solar is not unusually cheap or particularly expensive. In Cleveland, the average annual energy production for 5kW solar systems is 6,071 kWh, which means that every year Barb’s solar panels are producing that much energy. Assuming Barb’s system uses 250-watt panels, we then also know that Barb’s current solar array has 20 solar panels (250 W x 20 panels = 5,000 W). This means that each of Barb’s panels produces just over 303 kWh of energy in a year (6,071 kWh/20 panels). Let’s think of this number as Barb’s annual energy production for a single panel.

How much will it cost to charge a Tesla with solar panels?

As we learned above, Barb’s new Tesla Model S has a 31 kWh/109 MPGe rating. If we assume she will be driving 25 miles a day, we then know her Tesla is going to be using 7.75 kWh a day (about 2,829 kWh per year). Then – stay with me here – we can use our prior annual energy production value of 303 kWh/year and determine that Barb will need to add roughly 9 more solar panels to her system in order to completely cover her new Tesla and receive the seal of zero emissions approval from Mr. Musk.

The next question might be “how much does it cost to charge a Tesla with solar” or in other words, how much extra will Barb need to pay for those 10 panels. If we assume an average price for a standard panel is $185, charging Barb’s brand-new Model S will likely tack on another $1,665 to her solar panel system costs. Compare that to total money spent at the gas pump every year and we start to see why pairing a Tesla with solar cells makes sense. In the long run, Barb as a Tesla owner will see concrete energy savings on multiple fronts, and will likely break even on her solar panel investment in seven to 10 years.

Tesla solar chargers and the Tesla Powerwall

Tesla model S at solar charging station

If you’ve been following Tesla for some time, the acquisition of SolarCity should not have come as a shock. Tesla car charging ports with overhead solar canopies (as seen in the image above) have become a common sight in Europe and America, and the Tesla Powerwall is really the only solar battery brand that homeowners can cite by name. The Powerwall has seen numerous hurdles and criticism. However, Tesla successfully got the attention of mass consumer markets in bringing to light the benefits of solar-plus-storage as a highly efficient alternative energy solution. Tesla now needs only to sit and wait while its brand blows past the competition.

tesla_charging_station
Tesla Motors Wall Connector w/ 24′ foot Cable Charging Station

Out of Musk’s “Masterplan Part Deux” came a plan for Tesla to launch other electric vehicle models, including trucks and minivans, as well as a clean energy rideshare offering. We can expect the number of solar-powered charging ports to explode in the coming years. Even now, you can purchase Tesla branded wall-mounted charging stations for your home – an option that is sure to become more popular as the Tesla Model 3 hits the road across the country. These sleek, all-renewable power stations are a visual representation of Tesla’s mission as a corporation and their role will see dynamic value under the new era of Tesla.  

In a sense, the merger is just an upgrade of prior solar projects that Tesla flirted with in order to brand itself as a renewable energy company rather than a car company. The groundwork has long been in place for Musk’s clean energy integration – with the Powerwall, Tesla solar chargers, electric cars, and images of Tesla’s new, rebranded solar panel design already surfacing online, Tesla is fully and openly bringing its sleek, luxurious touch to the solar industry. While many were surprised by the acquisition, some Tesla owners are wondering why it took so long.

Common questions about Tesla solar chargers and solar car chargers

Can you charge a Tesla with solar power?

Yes, you can absolutely charge a Tesla with solar power!

How many solar panels are required to charge a Tesla?

About 10 panels are needed to charge a Tesla. This is only an estimate though; in reality, the number of panels depends on several factors, such as the solar panel’s efficiency, the model Tesla being charged, and what the power output of the connection being used.

How much solar does it take to charge a Tesla Model 3?

For the average American driver who commutes 30 miles every day, it takes about 7.75 kWh to charge a Tesla. It takes about 10 panels to capture enough solar energy to charge a Tesla.

How long would it take a solar panel to charge a Tesla?

Charging a Tesla using solar panels can take anywhere from 8 hours to several days depending on the Tesla model, sun exposure, energy output, and how much charge the battery requires to reach 100 percent. To use a particular example, there have been case studies that show a Tesla Model 3 takes 40 hours to charge under optimal conditions. 

How to find the best deal on solar

For those planning to go all in on clean energy, hopefully this breakdown helped you to envision the integration of solar and EVs. The next step towards zero emissions is to begin searching for the right EV and start comparing quotes for a solar panel system. The EnergySage Solar Marketplace allows you to compare real pricing data from homeowners in your area and review various financing options for free. For those looking for a personalized instant estimate for solar, try our Solar Calculator.


18 thoughts on “Charging your Tesla: how many solar panels does it take and how much does it cost?

  1. Bob

    Home charging is a challenge. A Nissan leaf charging for 8 hours would have an 80 mile range. At the Tesla Supercharging stations (not home use) you get a 150 mile range charge in 20 minutes. I live in an Ohio suburb close to interstate highways. The nearest Supercharging station to me is 4 miles. There are now over 30,000 of these world wide. In Ohio they are at every service plaza along I-80. There are 4 or 5 available on the each highways that circle Ohio’s largest cities. (The 3-digit numbers that just circle the city like 270, 275, etc.) I could go anywhere in Ohio with only one stop maximum. They have apparently partnered with gas stations to put these in. I don’t know if they charge for free like in CA. I want to see if they also do the battery swap. In 2014 Musk demonstrated the option to swap out the car battery -automatically- from underneath at the supercharging stations. That allows for getting a fully charged battery (320+ mile range) in seconds. That would also go a long way against the concern of cost when the battery goes bad. Check online you may be surprised how close a solar charging station is to you. I am not a global warming fanatic or green energy advocate. But this is exciting even to me that Musk has made solar powered cars practical. The trickle from home solar power (in Ohio) is a non-starter for me. I’d go with the 115v trickle to make sure I can reach the supercharge station, and do a battery swap each month.

    Reply
  2. Toby

    The diesel may not be “green”, but the 80-130MPGe is several times better than your gasoline car when considering the system as a whole.

    Reply
  3. Jonathan Lemaire

    A hybrid system is optimal, a combination of solar and microwind provides much more power even when the sun is down. The Tesla charging station near us is grid tied with a diesel generator…not green at all.

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  4. Graham

    25 miles a day, you have to be joking. Now that I am retired I still do about 30,000 km per year and most of that during the day. To charge my car at home would cost the earth in panels and batteries.
    Here in Australia they are discovering the cost to the grid of fast chargers (350 kw) which is about the same as 20 normal households. The picture that the user never sees is the generator producing that power to charge your car.

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  5. Michael Will

    For us in California, adding solar to your home often pays for itself in less than 7 years, even when oversized to also charge your cars.

    For our two car family with two adults commuting to work daily, we realized 2015 when we replaced our ‘secondary’ family car with electric, that we already had been paying $2400/year in electrical bills to PG&E because of hot summers, and admittedly, mediocre insulation. We realized that with just seven of those payments out of pocket, we could outright purchase and own 40 panels on our home for a total of 10kW which produce between 20kWh and 60kWh each month, depending on when in the year, which was more than needed to just erase the bill from the home but also had enough left over for one to two electric cars.

    We also quickly realized that we now were competing to drive the ‘secondary’ electric car and hated the formerly loved legacy gas car rminivan. 2016 we replaced it with a tesla Model X, and switched to an EV+Solar friendly time of use tarif and again had $1/year bill in 2017 for electricity.

    The Model X is definitely an unrealistic expensive luxury, but tesla.com/model3 starting at $35k and the upcoming tesla.com/modely are definitely choices that make economic sense from a total cost of ownership standpoint and not just from a convenience, fun, safety and fuel cost perspective.

    Most people don’t even know yet what they are missing, but to get back to the actual topic: We basically charge for free at home over night because that is when demand priced electricity is the cheapest, while we get credited two to three times as much for each kWh produced and fed into the grid in the daytime.

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  6. Michael

    The likely reason solar panels are not put on the car roof is that the consumer probably won’t notice the benefit. The 250W panel is about 5.5 ft x 3.25 ft so you’ll likely fit one panel on the roof. Assuming the math above, that panel will generate 830W a day but you’re consuming 8,250W a day. That 830W is assuming that your car is out in the sun the same amount of time as your house roof and it’s tilted at the optimum angle for your location, both of which are unlikely. That’s 2.5 miles in optimal conditions which is nothing. There’s that much variation in range depending on if your 25 miles is driven at city street speeds or highway speeds making the gains unnoticed by the consumer. Most consumers get upset if they can’t notice the value of something they paid for.

    Reply
  7. BASU N NAIDU

    BY BEING MORE INNOVATIVE WHY CANNOT WE HAVE A SOLAR PANEL ON CAR ROOF TOP ITSELF AND IF POSSIBLE ALL AROUND SAY THE TESLA CAR WE CAN SAVE DEPLEETING OIL RESERVES WICH HAVE BECOME A BURDEN ON THE ECONOMY

    Reply
  8. Mark Richardson

    I am curious why you chose Cleveland, OH for your cost-comparison, as that area gets a lot of rain. In-fact Cleveland has just slightly less than 50% rainy days annually. Just looking at our solar production here in Metro-Denver, a city with about 300 sunny days annually, from our 4000-watt system, which was new in 2014, during March, 2018 we produced 1,001.85 KwH, or an average of 32.31 KwH/day.

    We sold a fair amount of our production back to our power utility in-fact. So at-least for our system, its age, and location, each 250-watt panel produced 62.615 KwH/month. If your figure for the electric consumption of 8.25 KwH/25 miles is acccurate, then we only need to replace any amount over what we are selling back to our power utility now.

    Another question I have concerns your estimated payback period. Now let’s assume that your gal in Cleveland drives 25 miles daily on local city streets there, which during rush periods are slow to stop & go there due to non-snychronized traffic lights. Including having to start her engine at least 4 times per-day her fuel use is likely 1.5 to 2 gallons at a retail cost of close to $3.00/gallon.

    So just her fuel use daily is $4.50 to $6.00, plus the cost of 4 oil changes annually, let’s say $182.50, which works out another 50 cents per-day. Now most other operating costs are similar between gasoline-powered vehicles and EVs except the cost of tune-ups, air filters, oil filters (included in oil changes), and fuel filters, plus any fuel or exhaust system repair or replacement.

    Let’s assume one new muffler every 4-6 years of operation (more in Cleveland because of road salt), plus at-least a couple cans of fuel injector cleaner, plus 2-3 new air filters per-year, plus at-least 1-2 new fuel filters during the life of the vehicle. Gawd forbid you have to replace your fuel pump, fuel tank, oil pump, oil pan, catalytic converter, fuel injection system, or engine as any of these items will raise your cost of operating your gas-engine car considerably.

    Let’s just assume a total fuel and exhaust system operating cost for a gasoline-powered vehicle doing 25 miles per-day in Cleveland, not including depreciation, of $6.00 to $7.50 per-day, or 24 to 30 cents per-mile.

    Now using your stated costs for 250-watt solar panels of $185, times 10 panels is $1850. I will even add the cost of the charger at $150, which makes $2000. Let’s assume you drive your car 25 miles per-day, which works out to 9,125 miles per-year and that you drive your car for 10 years before trading it in.

    New solar panels today have a 30-year guarantee at 95% efficiency so let’s just assume 100% efficiency for 30 years. So your cost to charge your vehicle for 10 years is only 1/3rd the cost of the solar panels and the charger, or $667. If we divide that number by 10 (years) we get $66.70, and if we divide this figure by 365 (days) we get 18.2 cents per-day, or 0.73 cents per-mile.

    Here in Denver the cost to charge the car using rooftop solar is about 1/3rd of what the cost is in Cleveland or less depending on how much power you are already selling to your public utility.

    So even in Cleveland, charging your EV off your own rooftop solar power system is only 2.5 to 3.33% of the cost of operating a gasoline-engine car and in Denver the EV solar power charging cost is just 1/3rd of what the cost is in Cleveland.

    Reply

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