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Electric vehicles are gaining in popularity, but not everyone is on board. One of
the big perceived drawbacks is how long it takes to charge them and having access to
somewhere you can plug in to get that charge. If you live in an apartment building or the
city, charging can get a bit challenging. But what if you didn’t have to plug in
your car to charge? Some companies have solar-powered cars available for pre-order
today, but what’s the reality behind these cars? Can they really provide enough power to fit
the bill, and at a cost that won’t break the bank? I'm Matt Ferrell. Welcome to Undecided. The automotive industry is still in the early
phases of transitioning over to electric completely, which will most likely take another
decade or two. We’re seeing the rate of adoption towards battery electric vehicles (BEVs) increase.
Between 2020 and 2021, EV sales around the globe jumped 108%, reaching 6.75 million units in 2021.
Out of those, 71% were full BEVs, not hybrids. For comparison, in 2012 the total number sold was
125,000. However, BEV manufacturers still have challenges around consumer perception on issues
like short driving range and long charging times. That’s where solar power
may offer a few advantages. I’ve seen this question raised on a
bunch of my electric vehicle videos. Why not just stick solar panels on your car?
With a significant decrease in solar panel costs, a lot of EV charging locations and parking lots
are installing solar canopies. I see them a lot around where I live. Integrating directly onto the
car itself seems like a great option, because in theory you wouldn’t need to even plug your car
in in the first place. But what’s the catch? First let’s take a step back and look at when
the concept of adding solar panels to cars began, and how it’s fared so far. The history of
solar-powered cars goes back to the 1950s with William G. Cobb from General
Motors. Granted, calling this a car might be a little bit of a small exaggeration.
It was a tiny 15-inch model car powered by 12 selenium PV cells and an electric
motor. More like a car for squirrels. The first human-sized model showed up in
1962. It was a 1912 vintage model Baker that was converted by International Rectifier
and powered with 10,640 individual solar cells. If we jump ahead to 1980, a team from Tel Aviv
University in Israel developed a solar car that was powered with 400 W of solar cells, but it
wasn’t exactly a beautiful car. It was a car only a mother could love. With solar panels strapped
to the roof and hood, it had a range of about 50 miles and a top speed of 40 mph. It wasn’t going
to win any races or gain any points for style. In the years that followed, most
solar-powered cars were designed at universities for racing purposes
and pushing the technology forward, but none could be considered a viable passenger
vehicle. Things like range and weight capacity just weren’t there. However, in the last
few years, some companies are starting to push the idea that solar panels on cars
might be viable for a consumer product. Solar-powered cars offer several benefits. Just
like any other battery powered EV, they're silent, have zero emissions, and require less maintenance
compared to internal combustion vehicles. Recharging the batteries with solar power from
the car's roof can lead to fewer charging stops. If the car could be completely charged from the
sun, there would be no “fueling” costs to run the car … in theory. The question remains: can
the solar panels actually provide enough power? In a nutshell, solar panels generate
electricity to charge a battery pack, which in turn is used to provide
the power needed to move the car. While some of the prototype racing cars from
universities I mentioned directly power the car from solar panels without the need for
a battery, the cars coming to market still use a battery pack. All of these cars can still
be plugged in and charged up like any other EV. Although there's a massive amount of energy to
be extracted from the sun, current solar cell technologies still have fairly low efficiency ---
usually around 15-25% for solar panels --- which can make the math for how much electricity
you can generate given the amount of space … challenging. Cloudy weather, haze,
low sun angles and other issues mean that you might not generate enough
electricity to charge the batteries. So let’s break that down and attach a few
numbers to the problem. How much area is available for solar panels on a car? Now, I’m not
a mathematician, but let’s use the same line of thinking as Engineering Explained when he tried
calculating this ... with some modifications. Let's use the top area of a Tesla Model 3, which
is about 8.7 m². Let's say that about 60% of that area is usable roof space. If we covered that
entire area with solar panels, in the perfect scenario (where we'd make flat earthers happy
using a cross-section of the earth) the energy coming from the sun would be 1.36 kW/m². The
solar panels could generate 7.1 kW in total. For a 75 kWh battery pack, the solar panels could
fully charge the batteries in about 10.5 hours. I’m not a flat earther and we’ll be driving
this fictional car on the surface of a sphere, which means we’d only get
about 340 W/m² (4π.radius²), but it actually gets worse than that. Only about
55% of the irradiance would hit the car's surface since a significant portion is reflected back
into space or absorbed by the atmosphere. So a 20% efficient solar cell would give us
about 37.4 W/m² in a more realistic scenario. We also need to consider the efficiency
of the battery charging system. Let’s be generous and say it’s 95%.
The results: about 185 Watts. So to fully charge a Tesla Model 3’s battery
pack, you might need about 405 hours. That’s about 17 days to fully charge the car. Not
bad if you drive infrequently, but impossible if you have a regular Monday to Friday commute. Oh,
and results may vary, depending on your location, which impacts the sun's angle on the
solar panels, time year, weather, etc. You’re not going to be 100% independent from
plug in charging. All of this sounds like a pretty damning conclusion that solar
panels on a car just don’t make sense. Even so, the companies that are starting
to push this technology are tackling a few things my extremely rough
math haven’t factored in. But before we get to that ... and also related
directly to it ... if you want to really learn more about engineering and designing solar
energy systems, you might want to check out the "Ultimate 2021 Solar Energy Course
For Electrical Engineering" at Skillshare. It's one of the many reasons I'm so happy to
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The first 1,000 people to use this link will get a 1 month free trial of Skillshare.
Thanks to Skillshare, and to all of you, for supporting the channel. Now back to the
companies pushing solar technologies on EVs. In 2017, the German startup Sono Motors, unveiled
their first prototype of an electric car with solar recharging, the Sion. The EV has 248
solar cells integrated into the body of the car that can boost driving range by 112 km (~70 miles)
per week on average, but could go as high as 245 km (~152 miles) per week in peak conditions.
Using a fast-charging station to top up, Sion takes about 35 minutes to fill the 54 kWh
battery pack to 80% state of charge. The total driving range for the car is about 305 km (~190
miles) and has a top speed of 140 km/h (~87 mph). Sono Motors has already made
pre-orders available for Sion, but the production isn’t set to start until 2023
with a purchase price of €28,500 (about $32,361). The company plans to deliver the
first 14,000 reservations in 2023. In addition, they're also evaluating
solar integration into large vehicles. For example, by integrating thin-film solar panels
onto a truck with a 13-meter trailer, under peak conditions in Munich, the roof and sides equipped
with solar cells could generate 82 kWh per day. This could result in up to 80% saved energy cost
for refrigerated trailers compared to diesel. There’s also the SUV market. In 2021, Fisker
revealed the Ocean SUV with a solar roof. The company's SolarSky roof technology can produce
energy to provide between 1,500 to 2000 miles (~2,400 - 3,200 km) a year. They have five models
with driving ranges between 250 and 440 miles. They start at $37,499 and go up to $68,999. The start of production is scheduled for the
end of 2022 and they just recently announced that they have over 31,000 reservations
(about $1.7B in potential revenue). Again, you’re not going to cover all of your daily
driving needs, but make a small dent in it. Another company developing solar electric cars
is Lightyear, which unveiled the Lightyear One in 2019. This is where the potential
range generated per day takes a turn. Their long-range solar-electric car has five
square meters of a patented double-curved solar array that achieves 215 W/m². According
to the company, 1 hour in the sun can provide about 12 km (~7 miles) of range, and at the
end of the day, this can result in 70 km (~43 miles) of extra range. That’s basically the
average number of miles driven per day in the US. One of the big reasons for the high range
added per day doesn’t come from the solar panel efficiency, but the cars' efficient
use of that energy. It uses about 83 Wh/km. Compare that to the Tesla Model 3 at about 167
Wh/km. It's expected to reach a driving range up to 725 km (~450 miles) based on the Worldwide
harmonized Light vehicles Test Procedures (WLTP). So take that with a grain of salt until we
see real world results. The downside for those incredible numbers? The selling price for their
car is about €150,000 (equivalent to $170,321) excluding taxes … but it’s expected to be
available to customers starting this summer. On the flipside of those great mileage and
efficiency numbers are some of the bigger auto manufacturers, like Hyundai and Mercedes, who seem
to just be slapping solar onto existing designs. A limited edition version of the 2022 Hyundai
SONATA Hybrid is equipped with a 22.8% efficient solar roof that, under ideal conditions,
will increase the driving range by 2 miles per day. This kind of highlights the difference
between slapping solar panels onto an unoptimized car design vs. building a new solar powered
car from the ground up with efficiency first. However, these are a bit easier on the wallet,
starting at $35,550. Mercedes Vision EQXX is in a similar boat, albeit a little bit better
for range added. The 117 solar cells on its roof will provide about 25 km (~15 miles) of
extra range in a day under ideal conditions. This brings us to the solar powered car company
that’s really lighting up the competition: Aptera Motors. This is where the think outside the
box, build from the ground up approach really hits its stride. This futuristic three-wheeler has
been designed to be extremely energy-efficient, being able to reach up to 1,000 miles on a single
charge. One of the keys to that incredible range is its light weight, weighing 65% less than
a common EV. Combine that with its efficient drivetrain and aerodynamics and you’re using only
30% of the energy of current EVs and hybrids. This is not just about slapping solar panels
on a car, but rethinking the whole approach. How much range would you get with its 700 Watts
of solar cells? I live in Massachusetts, so let’s use that as an example. If I drove 30 miles a
day, considering the local sunlight conditions, I may only need to charge an Aptera about
twice per year … in theory. It’s capable of providing 16-40 miles of extra range to
the car depending on the conditions. After some fits and starts the company finally
opened up pre-orders in December 2020. Aptera’s production and first deliveries
are expected to start this year with a price ranging from $25,900 to $50,700. That’s
the best price to range of the entire lot, but it’s also an incredibly unique looking
car, which might not be your cup of tea. The big issue with most of these models is
that they can't be completely solar powered, but they can make a dent in the amount of plug-in
charging you’d need. There’s also the issue of limited real estate available for solar cells
to be integrated onto the surface of the car. Transparent solar panels could be used
for vehicle windows to produce power, but as we saw in my video on that
technology, current transparent cells have much lower efficiencies and
power densities than silicon cells. The combo of limited surface
area, low solar panel efficiency, and vehicles that aren’t designed
from the ground up with this in mind, makes this not as compelling from a cost
benefit perspective. However, for vehicles that are purpose built for this, like Aptera or
Lightyear, the numbers look a lot more appealing. So do you want to own a solar powered car? Do
you think we’ll see more of this in the future? Jump in the comments and let me know. And if you
have knowledge on this, or work in the industry, please share your experience so we can
learn more together. You can also join my Discord server and talk to other members of
the community. The link is in the description. And thanks as always to my patrons and a big
welcome to new Producers 4 Fission NOT Fusion and David Hailey. All of your direct support really
helps with producing these videos and to reduce my dependence on the almighty YouTube algorithm.
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