Misconceptions of the Electric Vehicles
There are a lot of misconceptions about the Electric Vehicles, not only from consumers but also from designers and manufacturers. They are made worse by journalists and media reporters. They are just so ignorant that they are reporting incorrect information about the Electric Vehicle technology.
The most recent announcemnt of the Mercedes Benz EQXX is an example. It was reported as a very efficient electric car with a large range, 1000 km. Its efficiency of only 100 Wh/km is disappointing when Lightyear One can achieve 83 Wh/km. Even Lightyear One cannot beat the Stella Vie with 48 Wh/km.
1. Solar Cars are not practical. Cannot carry any passenger.
Lightyear One is a big car at 5057 x 1898 x 1426 mm compared to the EQXX.
https://lightyear.one/lightyear-one
Stella Vie and Era are even smaller so their less than 50 Wh/km ability is to be expected.
Stella Lux can run 650 km usin 15 kWh battery for 23 Wh/km with 97% motor efficiency.
https://www.europhysicsnews.org/articles/epn/pdf/2017/03/epn2017483p13.pdf
https://en.wikipedia.org/wiki/Stella_(solar_vehicles)
Stella Vie did 3021 km, using 45.7 kWh which is 15 Wh/km.
Stella Era did 70.2 km/h and charged only an additional 71.24 kWh, which is 24 Wh/km on battery.
https://inhabitat.com/cambridge-students-create-the-uks-most-efficient-solar-powered-electric-car/
I base these misconceptions on my latest discussions in social networkds in UK, Speak EV and Reddit. Unfortunately I was banned for pointing out their very obvious mistakes and misconceptions.
Therefore the expected efficiency of the Transparent SUV of 50 Wh/km is reasonable given its more aerodynamic shape and covered wheels.
Despite these news, the public in UK still believes solar powered cars cannot carry any passenger.
2. Solar cars will have no range at all. Less than 1 mile or 1.6 km in UK.
Because UK is mostly cloudy, especially in winter, a solar car will not move at all. At most 1-3 miles. This is based on their experiences with roof-top solar panels and their existing electric car.
What they do not realise that current technology allows more than 5 times the efficiency of electric energy consumption. From more than 200 Wh/km to less than 50 Wh/km. Even in the cloudest days, there should still be sufficient sun to drive a completely empty solar car a few km to a charging station.
https://en.wikipedia.org/wiki/Solar_power_in_the_United_Kingdom
"London receives 0.52 and 4.74 kWh/m2 per day in December and July, respectively"
With 5 sq. m of solar panel with an efficiency of 20%, in London in December, you can collect 520 Wh of electrical energy per day. Enough to travel 10 km.
They also assume that you can only put a maximum of 4 sq. m of solar panel on a car. A specially designed solar car will have more than 5 sq. km of solar panels. Efficiencies also has gone up from typically 15% to over 20 %.
3. Vectored steering will wear out tyres quickly
Transparent SUV will not use any steering. It willl use vectored steering. It was brought about because of observations of the difficulties in tyre alignments that made the tyres wear out faster. The obvious solution is just to fix the tyres to point forward all the time. Steering done by adjusting the speed of the wheels. This done by toys all the time successfully.
One comment said that the Triumph Herald had good turning and allowed easy parking using the Ackermann steering, but tyres worn out faster. He thought Ackermann steering is vectored steering, but actually modern steering is Ackermann. He must have recalled these problems first hand but wronly attributed it to vectored steering.
Instinct tells me also that tank turns will wear out tyres but there is no data to prove this. Even if this were true, it will be only slightly worse than existing steering systems that are difficult to align properly. Having the wheels point out in front will make alignment easy. Also, makingg turns is not common. Most of the time, the wheels are in a straight position.
However, I have thought about allowing some adjustments of the trailing arm steering to alllow some steering for all wheels. The meachanism for alignment adjustment is used to turn the wheels slightly. Just turn the steering out of adjustment when we want to steer but will return to a straight position on idle.
4. EV cannot match ICE range and refueling
One commenter challenged that he will never buy an EV that cannot do 400 mile range be charged in less than 5 minutes like ICE. Already being done by a few vehicles but they are costly. Transparent SUV can achieve that at a cost of less than 20,000 pound. Just remove solar panels and super capacitors and fully upgrade the battery from 10 kWh to 30 kWh. Its range will therefore be 600 km. Because the batteries of the Transparent SUV are replaceable, battery swapping can be done in 5 minutes, not as fast as NIOS though, which can do it in 3 minutes.
The person opting for swappable batteries will have to pay 20,000 pound for the service, which is like buying 60 kWh battery. 3 kWh inside the Transparent SUV, 3 kWh to be placed at charging stations near the places where the buyer register his car, at most 600 km away. The subscriber can go to these battery swapping stations and get their batteries replaced in 5 minutes.
It can be done, but what is the point of it all. My recommendation has always been to be on the safe side. 200 km range becasue drivers need to rest after 2 hours of driving. The same driver needs to rest for at least 30 minutes, so can use the time to charge the 10 kWh battery, which is a small battery. Customers are always right, so we just have to provide options to them. They just need to pay an extra 10,000 pound.
Unfortunately, this may not be the reason because there may be other additional demands such as handling must be superior to ICE. Because Transparent SUV uses a narrow track and cheaper suspension and steering, its handling will suffer. It may be possible to program the handling characteristics but air suspensions are slow to respond to any adjustment.
5. Wheel hub motors have problems
Low Torque
The problem with direct drive motors is that they have no gear to increase torgue at low RPM. Actually, torque can be increased by increasing current. The large current will make the motors hot. That is why a lot of direct drive motors got burned when climbing hills.
Tesla cars have oil cooling to cool the motors and controllers. Hobby racers install hub heat sinks and even magnetite lubrication to cool wheel hub motors. Although these cooling will still not match the torque of motors with gears, the lack of noise and therefore low energy loss is a worthy gamble. We may even have to push the car, like we do for ebikes.
Sacrificing low speed torque over efficiency at low speed only, is not a major tradeoff, but ebike manufacturers have abandoned wheel hub motors in favour of mid drives with motors because they give better handling.
https://electrek.co/2018/06/07/electric-bicycle-hub-motors-vs-mid-drive/
https://www.linkedin.com/pulse/hub-motors-future-choice-ev-powertrain-murali-krishna-u/
Unsprung weight
Another misconception is that high unsprung weight. It was due to paper by a tyre manufacturer that showed that unsprung weight causes poor handling in cars. Normal suspension setting will result in poor handling but Lotus has proven that suspensions can be tuned to have good handling even with high unsprung mass.
https://chargedevs.com/newswire/lordstown-electric-pickup-to-use-in-wheel-motors-a-good-idea/
https://chargedevs.com/newswire/lordstown-electric-pickup-to-use-in-wheel-motors-a-good-idea/
“For some small efficiency gains (all the advantages mentioned in [a Motor Authority article] also apply to body-mounted 4-motor systems like Rivian), the Lordstown will have the strong possibility of worst-in-class ride and handling due to high unsprung mass. Not only that, powertrain unreliability is highly probable from mounting the motor and electrical components on a constantly moving platform that is exposed to high shocks and forces.”
The misconception that the efficiency gain is small should look at the data. Every small gain in efficiency is vital in an electric car. For example, the EQXX consumes 100 Wh/km whereas, full wheel mounted motors, Lightyear One can acheive 83 Wh/km. This is huge and will lead to other gains such as smaller batteries.
The problem with ride and handling had been proven to be non-existent with properly tuned suspensions.
It is true that the motors have less protection apart from the tyres but electric motors are tough. Waterproffing can be done easily and cheaply by just painting with silicon.
Transparent SUV has high ground clearance and therefore larger tyres to absorb the shocks. More shock absorption can be designed into the system if required.
Here’s what Steve Williams of Lotus Engineering said:
Whilst it is true to say that the vehicle dynamic performance was degraded by the increase in unsprung mass, the degree to which this was noticeable was small and could be said to have moved the overall dynamic performance of the test vehicle from class leading to mid class. Further more, the understanding gained from this study has led Lotus to believe that the small performance deficit could be largely recovered through design changes to suspension compliance bushings, top mounts, PAS characteristics and damping, all part of a typical new vehicle tuning program.
Add the powerful benefits of active torque control and Lotus’s finding make a strong argument for the vehicle dynamics benefits of hub motors as an EV drivetrain.
Croatian supercar builder Rimac uses a 4-motor design, but these are not in-wheel hub motors. “In-wheel hub motors add unsprung mass that results in higher stress to suspension components,” founder Mate Rimac told Charged in 2016. “Our motors sit low and inboard, close to the center of the car, which we consider to be better for vehicle dynamics.”
The higher stress on suspension may not be true. There is less sprung weight to support. There is also a severe loss in higher centre of gravity of the motors. The extra aerodynamic losses is disastrous for high speed performance for gains in low speed handling.
Several suppliers, including Elaphe, Protean and Nidec, have developed in-wheel motors. Aptera, a startup that’s building an ultra-efficient EV, says Elaphe’s in-wheel motors offer advantages including enhanced aerodynamics, lower vehicle weight and low energy usage.
For the Transparent SUV, cost is the most important issues. Efficiency is second. Handling is low in its priority. Handling and ride will be handled by computer, just like fly-by-wire fighter jets.
6. Plastics is not safe
The first response to any suggestion of making a plastic body of a car is that it is not safe. It is strange when you look at toy cars.These scale cars are all made of plastics and they all are strong and rigid and even indestructible.
Acrylic is brittle but not as brittle as glass. I was even misled into thinking that acrylic is very dangerous if it shatters but my CD cases break just like wood. The splinters behave like wood splinters. If we say that acrylic is dangerous then wood is also dangerous when they splinter. The safest in fact are the plastics used to make toy body shells. They tend to be PET or just PVC and they are more flexible. I was surprised that even with a thickness of 0.5 mm, a 1/10 scale is rigid and take the shape of cars. For scale cars, these flexible car bodies will not be acceptable because they rattle. Visibility is also poor. Acrylic is clearer and scratch resistant but not as scratch-proof as glass. We may have to put a think layer of tampered class protector at the windscreen, just like our mobile phones.
Strange thing also is that it does not appear to many people that we can put frames in a plastic body shell. For thin shells, 0.5 mm, we may need frames when we make many doors. Toy cars are strong because they do not have any door. I do not think that if we put 20 kg of weight on top of the body shell, it will not break which is a requirement for safety against body roll. For 1,000 kg, its roof must be able to withstand twice the load, which is 2,000 kg. Because scaling effect for deformation is the square, a 1/10 scale model should withstand 20 kg of load put on its roof. However, a 1 mm thick plastic body shell will be able to withstand the load, especially at the vertical edges. The central flatter part of the roof will crack but a large point force should not be put at the centre of the roof alone.
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