EVs already have better mileage and better range. The concept is just completely misunderstood.
Mars Rovers say no to ICE
It is said that an average gasoline car provides a better range. But Caltech’s Jet Propulsion Lab and its five Mars rovers would strongly disagree. Sojourner lasted 83 sols (Martian Days), Spirit lasted 2210 sols, Opportunity lasted 5111 sols, Curiosity and Perseverance are still persevering. Chinese Zhurong lasted 347 sols. These long missions would not have been possible without electric motors and solar panels. No refilling, no lubricants, no maintenance, unlimited energy. So, how long would these Mars rovers have lasted if Otto Diesel had his way?
Guinness Book of Records
How far can the most efficient Internal Combustion Engines (ICE) go? A Polish professional driver holds the Guinness World Record for the longest drive with his Skoda Superb. On one single 66l fuel tank (ca. 17.4 gallons), the car and driver achieved 2,831 km (1,759 miles). I don’t really understand how this record works, but the final numbers for this most economical driver was 2.6l/100km. That Skoda has great aerodynamics (0.23), and the speed was an average of 85km/h (<55mph). But this was just a regular 2.0TD achieving almost 90mpg – just by driving better. But wait, there is more …
The only 1.0L Gasoline Car
Don’t get me wrong, 2.6l/100km isn’t too shabby. But the holy grail for the automotive industry has been to achieve 1 liter for 100km. That would be almost 240 mpg. So far, it has not been done. Even the grandson of Ferdinand Porsche – putting all his power and money behind it – could not achieve this feat in a production car. But then he did … sort of. After years and years of trying to build a real “1 Liter Car,” he finally surrendered and added some EV parts as well. Now his Hybrid car even overachieved with 0.9l/100km (>260mpg).
Dr. Ferdinand Piëch was one of the most influential men in modern automotive history. I bet few people have ever heard of Austrian Ferdinand Piëch and all his achievements. Had his mother Louise Porsche kept her maiden name – this would have been totally different.
The VW XL1 was a two-seater production car with a 1.6-liter TD engine that reached 100 km with just one liter of diesel and one fully charged 5.5 kWh battery pack. Basically, 10L of diesel engine provided around 450km, the battery added 50km and – most importantly – captured regen energy when braking. A very low drag coefficient (<0.19) combined with the feature to gain energy while driving was key. The combined 500km on a 10-liter tank was enough to qualify this car as the first and only 1 1-liter car.
Unfortunately, this car came out a few years too late. By 2011, the price tag of $140,000 was too high compared with all the EVs and affordable hybrids on the market. They weren’t that economical, but they were more affordable and available. But this car is definitely a classic and a dream for some geeks.
Renewable Energy wins the Race
The 1990s were the era of solar geeks doing all kinds of DIY projects. Plenty of universities and DIY geeks kept electrifying their cars, bikes, even boats by adding solar panels and often just standard lead-acid car batteries. This was supported by several solar vehicle competitions around the world, with names like Sunrayce, European Tour de Sol, or the World Solar Challenge crossing Australia. These races promoted automotive engineering and understanding of solar energy among college students and engineers.
SunRayce
General Motors (GM) sponsored a competition named SunRayce. It was a multi-day, long-distance electric vehicle rally. Events were held every two years starting in 1990. Teams had to work within certain design and safety specifications. The focus was on speed – these solar cars reached 50-60 mph. But more focus was on distance and endurance. The vehicles would start with a full battery in the morning, and depending on the sun and the landscape, they could drive all day long until they reached the end of a stage. In 1990, they covered 1,800 miles; in 1999, it was 1,400 miles.
The American Solar Challenge (ASC)
By 2000, SunRayce became the American Solar Challenge (ASC). That race covered 1,800-2,000 miles, and cars now reached speeds of 85 mph on these tires and a closed race track. But 85 mph isn’t an economical speed. Slower speeds get you much farther. During the first stage, the University of Michigan covered 506 miles over two days with an average speed of 33 mph. In 2022, the University of Minnesota car “Freya” could reach around 400 miles with a fully charged battery and sunlight along the way.
World Solar Challenge
SunRayce, or rather the American Solar Challenge, is grueling enough, but really just the minor league to qualify for the World Series of solar vehicles – The World Solar Challenge.
Teams from the American Solar Challenge (ASC) or the European Tour de Sol would come to Australia for an even more grueling test – 2,000 miles of Outback but without the steakhouse or the blooming onion. The race attracted teams from schools and corporations worldwide. Last year, the Belgium Innoptus Solar Powered Car achieved 98% peak efficiency, which is 2% more than a small Tesla and 40% more than a traditional ICE. That is also why these cars only need a battery size of 5KWh, whereas a Tesla Model 3 starts at 50KWh and the Model S has 100KWh and still might have a smaller range.
The “Perpetuum Mobile” of Transportation
The brilliant idea behind the Solar EV Vehicle is to create a Perpetual Motion Machine, so that a driver never has to think about range, charging time or fuel cost ever again. But if the sun is the friend of solar-powered vehicles, then wind resistance is the enemy. What all these solar competitions have shown is that a light-weight and energy-efficient design requires a low wind resistance. The form becomes the main function so to speak. To reach an unlimited range, like the Mars rovers, we need to add renewable energy and regenerative braking into the mix. We also need to address and incentivize mobility patterns.
There are currently several companies working on providing street ready Urban Solar Vehicles with even better range than VW’s XL1. The most well-known ones might be Aptera, Lightyear, and Sono.
The Dutch Lightyear 0 has almost 800 solar panels across its hood and roof, and a 0.19 drag coefficient. It’s definitely using more power to drive than is generated during driving, but when the car is parked, it can be replenished with free energy. Or if you park a regular EV in the sun for a longer time, the battery might be depleted just for the occasional AC to cool the car and the battery pack. A solar car like this generates enough energy to take care of this and keep trickle charging. It’s range is supposedly 380 miles at highway speeds on a 60Kw battery pack. And this car looks suited for family highway driving.
German Sono Sion would come with solar panels that feed a 54 kWh LFP battery pack. And LFP means that the battery doesn’t burn up on impact, but most importantly, these cells have less degradation related to charging cycles. This is important when your car is constantly charging and discharging while driving and parking. The range of the pack is a reported 190 miles. Per their estimate, this car, used in the Bay Area, would get maybe 5,400 miles of driving out of these mounted solar panels, just by parking in the sun. That would be 10-20 miles per day. That might not get you through the whole day, but this is a 4-wheel family vehicle that looks and functions like a regular ca,r giving you free miles.
San Diego’s Aptera is supposedly adding 40 free miles per day just sitting in a sunny parking lot. For many people, that is enough to do all kinds of errands around town without ever having to plug in again. They claim to have a range of 400 miles with a 45 kW battery pack. Their drag coefficient is an astonishingly low – yet unconfirmed – 0.13. This solar three-wheeler is probably best suited for city driving.
So far, the theory. None of these cars will ever hit the road. These aren’t real car companies; they are DIY projects that have been overpromising and underdelivering. Two of these companies have already hit bankruptcy. The Lightyear 0 had a price tag of $250,000 and wasn’t a viable business model. I would have loved to get my hands on a Sion, but Sono ran out of money too.
Maybe San Diego’s Aptera is the last man standing. We wish them good luck.
The Future of Solar Vehicles
Turns out it is hard to build cars from scratch. Google tried it with their concept car Firefly; Apple was working on their own autonomous vehicle project. Those companies have the money to spend, but they still stopped those projects. Looking at these smaller companies and the technology improvements they represent just proves how hard it was for Tesla to become the US market leader in EV technology. It also shows how quickly such projects can be doomed.
Who wouldn’t like a $20,000 car that charges while you drive or park, and basically gives you 3,000 miles of additional range per year? Most leased cars allow 10k-12k per year in driving, imagine getting 25% of those miles for free. These Solar Vehicles would be superior technology for Autonomous Taxis since currently, the time that could be used driving is wasted on charging. Had a Tesla Model 2 or Roadster with similar features to some of these Solar cars, including a working FSD, Tesla would be world-leading again.
Post.Scriptum.
Talking about Tesla brings us back to Mars. These rovers essentially achieve infinite mobility as they can charge more energy than they use. And the key to success is a small vehicle, short distance, low speed, no wind resistance issue, plenty of time. No ICE vehicle would work in these conditions.
But would these rovers have been able to leave Earth without chemical combustion or fossil fuels? Currently, there is no solid technology to bring rockets to space with electric motors; we still need some explosiveness here. So the answer if gasoline or electric vehicles have the better range is the false narrative. The focus must be on using the perfect technology for any given scenario.Â
NASA has demonstrated how EVs based on renewable energy are vastly superior in long-term, maintenance-free scenarios. These solar competitions were supposed to prove that electric vehicles could be a viable mode of transportation on Earth as well. In a post-apocalyptic Mad Max world or the Australian Outback, I would rather own a Solar Vehicle than run out of gasoline. And if it is lightweight and has pedals, it could have almost unlimited range. In the end, this Perpetuum Mobile of Mad Max Transportation will have the last laugh.Â
More Information
- Wikipedia: Ferdinand Piech
- Sunrayce Challenge
- Electrek American Solar Challenge results
- World Solar Challenge
- Stanford Solar Car Project
- Video: American Solar Challenge
- Video: World Solar Challenge
- Video: 3 interesting Solar Car projects
