The Electric Car’s (And Motorcycle’s) Highway Problem – And 3 Solutions

Electric cars have a problem. No. It’s not about their limited range. Or slow charging times. Or limited charging infrastructure. It’s about their inability to efficiently cruise at high speeds.

This is not a new problem for the auto industry. The petrol and diesel engines have suffered from narrow torque bands since their birth. Engineers found a way around this problem by adding multi-speed transmission. As long as a car’s engine stays between a specific RPM range and has enough torque available there to overcome the weight, frictional and aerodynamic drag, it can cruise efficiently. The onus of changing gears can be upon you or an auto-box.

Unlike petrol and diesel cars, electric cars don’t have a multi-speed transmission. So, how do they attain high speeds? By revving some more. A Tesla Model S, for example, can rev up to 18000rpm. With a fixed-ratio drivetrain, the motor adds 1kmph of speed for every 90rpm. Compared to an internal combustion engine, 18000rpm is downright bonkers.

To see how it delivers that performance, let’s consider the middle-of-the-road Model S 85’s performance graph. That’s the green line shown below. The solid line is for the torque in Nm and the dotted line is for power in kW. As you can see, its peak torque of 445Nm comes in pretty much as soon as it starts rolling. It stays strong till about 78kmph (7000rpm) and then starts dropping. The power curve keeps ramping up till it reaches 323PS and then stops making any progress as the torque drops off. But when the torque really starts to catch the gravity at about 130kmph (11700rpm), the power starts dropping too.

If you’ve fallen for the horsepower trick that carmakers play all the time, then allow us to break it down for you. Power is a result of torque at a given RPM. There’s also a constant involved, but in simple terms, know that Power = Torque X RPM.

So, the strong acceleration you feel in any car is actually the result of strong torque at those RPMs. The graph here clearly shows the relation between the two. While the torque is strong, the power keeps rising with RPMs. But, depending on how rapidly the torque drops, the power starts fading too.

Based on the Tesla Model S power graph, it’s clear that the motor is not making the same kind of torque beyond 7000rpm.

Sky-high revving electric motors aren’t just limited to Teslas. The Renault Zoe also revs to an astounding 11300rpm. Its motor adds 1kmph to the speedometer reading for every 82rpm increase in the motor revs. It makes 110PS of power from 3395 to 10980rpm. That should give you an idea about where the torque starts its downward journey. The figures sing the same song. Its peak torque of 225Nm is available between 1500 and 3390rpm. That number is like deja vu. In typical electric vehicle fashion, there would be a healthy amount of torque below 1500rpm as well, but in this case, it peaks at 1500 and stays put till 3390rpm.

Judging by its peak torque figure, we can say that you’ll experience the best of its performance up to about 42kmph.

Now, let’s talk about the efficiency part of an electric motor and why you shouldn’t rev it hard.

The above graph shows the battery power consumed at a given speed (yellow), aerodynamic drag (red) and the power required to compensate for the increase in aero drag (blue). As you can see, the actual power consumption and power required to deal with the aerodynamic drag at 30kmph is same. However, once the speedometer starts climbing, actual power consumption increases drastically – far beyond what’s needed to compensate for the aero drag.

The reason for this exponential increase in battery power consumption is inefficiencies in the electric motor itself at higher RPMs. That’s not unlike petrol and diesel engines. Similar to a combustion engine, revving the guts out of an electric motor can not only cause excessive damage, overheating and premature failure but will also consume excessive battery. In simple terms, cruising at 50kmph and 100kmph is not the same in an electric car with a fixed ratio transmission. You will get better range per charge if you cruise at a slower speed in an electric vehicle. How slow can you cruise without hampering the range? Well, that depends on the peak torque rpm of the electric motor.

Here’s a video of Tata Nexon electric getting a boot-full of accelerator:

https://www.youtube.com/watch?v=BmeFaaJ4g_M

Things worth noting here are the estimated range, distance covered during the test displayed in the trip meter and power consumption. In the beginning, the estimated range is 101km, the trip meter reading is 4.8km and average power consumption for that trip was 132Wh/km. By the end of this short video, the range drops by 2km while the distance covered is only 0.8km. The power consumption at the end is 163Wh/km.

I did the number-crunching for you and found out that during that 800m run, it consumed about 280Wh/km. So if you drive it at its top speed, you can expect to go about 108km on a full charge of its 30.2kWh battery pack. That’s an efficiency of just 3.6kmpu. Tata expects the typical usage to stay under 100Wh/km or 10km per unit (kmpu) of electricity. That’s because the regen is also expected to add some range back into the batteries.

It means that despite its 129PS of power and 245Nm of torque output, the Nexon electric isn’t meant for the highway. It’s supposed to be used in the city. Tata Motors also confirms our suspicion by not offering cruise control in the Nexon electric. The petrol and diesel models of the Nexon facelift get the highway-friendly feature. If you intend to use your Nexon electric on the highway – at highway speeds – then expect far less than the advertised 312km of range.



Solution #1 – Multi-Speed Transmission

Driving a manual transmission in stop-and-go traffic is a lot of pain in a petrol or diesel car. But in an electric car, it won’t be as miserable. Even when you’re fully stopped, an engine keeps revving. While the engine is idling, you keep your car from crawling past a stoplight either by braking or by pressing the clutch pedal and disengaging the drivetrain. An electric car doesn’t rev at idle. So, you don’t need to do any of those things. Even when rolling off in an EV with a stick shift, you won’t have to lift off the clutch carefully. In fact, to get moving, you don’t even need to use the clutch as there’s no mismatch of speed between the engine and the wheels – they’re both at 0rpm.

A transmission adds ~40kg of weight to a mass-market car but you can use it to get better mileage and speed. It can allow you to drive your electric car efficiently at high speeds. It doesn’t need to be a 5- or 6-speed gearbox like normal petrol or diesel cars. Even 2- or 3-speed transmissions are more than enough to efficiently drive an electric car on the highway – at triple-digit speeds. Those who don’t like the manual transmission can just slot it in their preferred gear and drive it like an EV with a single-speed transmission.

Porsche is already doing it. Could you imagine the embarrassment of buying a Porsche and not being able to drive it on the Autobahn? You can’t drive a Tesla the way you should on the German expressway with no speed limit. That’s why the Porsche Taycan has a 2-speed transmission. So, even after hitting 120 – 130kmph, it can continue to pull like crazy to its top speed of 260kmph.

A multi-speed manual transmission, though, could be especially exciting for enthusiasts as it allows us to gain some control over the vehicle. With a manual gearbox, a driver can better exploit the electric car’s bottom-end torque and enjoy an engaging drive slotting gears.

Since it’s not a completely new concept, it shouldn’t cost a lot in R&D. The tech already exists. It just needs to be adapted to work with electric cars. If Porsche can do it, so can others. Its benefits aren’t just limited to high-end cars. While the performance-focused electric cars can get better top speeds out of a multi-speed transmission, a budget car could leverage it for a better driving range.

Multiple electric motorcycle manufacturers – Indian and foreign – have decided to add multi-speed transmissions to their vehicles, which further validates this theory. eMotion’s Surge, Tacita T-Cruise and Kymco RevoNEX are in line to get a multi-speed transmission. It’ll allow their electric motors to efficiently utilize whatever little juice their batteries can store in them. It’s all the more important for a motorcycle to keep its weight in check as the rider has to manage it at parking, city, and cruising speeds. The fact that electric motorcycle makers are choosing multi-speed transmission instead of more batteries to get longer range suggests that adding more batteries to achieve similar range may have a worse weight penalty.

Here’s what the founder and CEO of eMotion, Pranav Singanapalli, had to say to justify adding a gearbox to the Surge electric motorcycle:

“We have 3 reasons – the first is we want to preserve the experience of riding a conventional motorcycle. We want to keep the experience familiar to a traditional bike owner. Secondly, it is the efficiency – the motor has an rpm when it delivers the best efficiency, and we can maintain that with the gearbox and thirdly we can offer great torque and acceleration without compromising the top speed.”



Solution #2 – Add More Battery

Adding more battery is one of the options to get a decent range from an electric vehicle on the highways.

The obvious problem with this is the cost. Although the cost of lithium batteries has dropped drastically in recent years, it’s still the single most expensive component in an electric vehicle. Making EVs more expensive isn’t going to help them spread the good word.

The not-so-obvious issue with adding more battery is the kerb weight. If you only occasionally need to drive on the highways, lugging that extra weight of the batteries around the city makes little sense. Not to mention, its adverse effects on the life span of the car’s tyres, brakes and suspension. It’s good insurance, but a heavy one – literally.



Solution #3 – Empty Slots For Renting Battery

Let’s say your car has slots for 50kWh worth of batteries but you only need 200-250km of range from the electric car for 99% of the time. Well, then just ask for a car with a 25kWh of battery and leave the rest of the slots empty but easily accessible. When you want to make a highway trip, rent 25kWh batteries from the dealership for a week or two, fill up those empty slots and enjoy ~500km of range at modest speeds. Or about 300km at highway speeds. This strategy will also keep the upfront costs of the vehicle down and leave the option of adding more battery if and when needed.

Having a serviceable hatch mechanism for storing batteries also opens up the possibility of significantly cutting the revival times and lowering the upfront costs of the car. You can buy the car without the battery. Just lease them instead. Rather than waiting for hours recharging your car along the highways, it could be possible to just replace the batteries at an outlet. It drastically cuts down the time required to top up and hit the road again. Since you don’t own the batteries, you don’t need to worry about the condition of the replacement either. Third-party battery makers can also chip in to offer competitive prices for a replacement battery pack for your car.

References: Electrek

MyRenaultZoe

EVSpecifications

(The article is written by Mahesh Yadav. Mahesh is car and motorcycle lover. But unlike most enthusiasts, who can’t have enough, he believes that great things come in small packages. As a fan and firm believer of the ‘Just enough. Just in time.’ theory, he loves the underappreciated vehicles that offer just enough to meet the consumer needs for as little cash as possible. The list of his favorite cars includes the Eicher Polaris Multix, Tata Nano, Honda Brio, Mazda Miata, MG E200, and the likes.)

Not so impressive stalls at the 2020 auto expo

After listing down the top 3 star brands of the 2020 Auto Expo, it’s now time we walk you through the brand stalls that could have done better. Places with carmakers that make you rethink your decision to buy the ticket to the expo. Stalls that need to give us more reasons to look forward to their cars. Let’s get counting –

1. Mahindra:
Mahindra was by far one of the biggest disappointment at the 2020 Auto Expo. The Funster was sure an eye candy but it smells like vaporware, just like the XUV Aero. Mahindra also launched eKUV100 (Rs. 8.25 lakh) with a laughably low range of 147km. For an electric car launching in 2020, 147km of claimed range is unacceptable, knowing that the real-world range is going to be worse – especially if you get stuck in traffic on a hot day. Mahindra also showcased the eXUV300 – which is not ready for launch yet. Unfortunately, neither of these cars are above 4 meters long, which means their petrol/diesel-powered rivals enjoy the small-car tax benefit. Unlike a sub-4m car, a bigger SUV, which suffers from higher taxes, is easier to compete with on the electric front. Mahindra had none of that at the auto show.

Mahindra Funster

While other carmakers are trying to hype up electric vehicles to make them desirable, we could see Mahindra attempting to capture the uninspiring end of the EV market. The idea was further reaffirmed with the showcase of the Atom at the expo. It’s their electric alternative to the auto-rickshaw, with AC, touchscreen infotainment and a phone mount. It’s clearly made for shared mobility platforms like Ola and Uber. The charging could impact its uptime as several fleet owners run their cars all day and all night with 2 drivers working in shifts. Prices aren’t out yet, but the higher cost of acquisition than a 3-wheeler could also affect its adoption. It rivals the Bajaj Qute.

The next-generation Thar and next-gen XUV500 would’ve done better as showstoppers. The bigger XUV, (a.k.a. the money maker) especially, is witnessing the ‘rise’ of new challengers every other day.

All things considered, Mahindra could’ve put up a better show with by showcasing newer models of cars that are nearing the end of their life cycle. But they didn’t.



2. Volkswagen Group (VW, Skoda):

Skoda and Volkswagen have a reputation for making reliable, refined, and punchy turbocharged diesel engines. For some reason, they’re turning their backs on diesels and moving towards the turbocharged petrol engines, which, while pretty good in their own right, aren’t heroes of reliability. When paired with a dual-clutch transmission, their poor resale value reflects our “love” for cars without a proven track record of reliability.

Moreover, the VW Group showcased T-Roc, Taigun (wonder how that name’s gonna age?), and Vision IN. All three are hoping to bite a slice out of the compact SUV pie but only the Skoda Vision IN seems to have the dimensions and stance to pull it off and please the Indian audience. The Volkswagen “SUVs” are too small and too sedate for their own good. Hell, some subcompact alternatives like the Kia Sonet and Ford EcoSport look more butch than the Taigun and T-Roc. Then there’s the question of pricing and positioning. Neither of these are less than 4 meters in length. So, VW can kiss goodbye to the tax breaks. That puts it in the race with some seriously competent, spacious, and powerful cars like the Creta, Seltos, Harrier, and Hector. Mind you, this is the segment where a lot of buyers still prefer a diesel powertrain, which VW Group has no plans to offer.

VW ID

Put together the lack of diesel engines, expectedly expensive compact SUVs that are barely over 4 meters, a competent lineup of rivals, and an overlapping product portfolio, and what you get a disastrous long-term outlook. Even with 13-15% lower part costs and heavy localization. If Mahindra can find a way to fit the Tivoli under 4 meters, Volkswagen has no excuse for not having a sub-4m SUV at the 2020 Auto Expo.

Before you bring up the I.D. Crozz, let me clarify that it’s too far into the future and would be too expensive to have a measurable impact on the volumes and the bottom line.



3. Renault

At the 2020 Auto Expo, Renault pulled the wraps off a car we can walk into the showroom and drive home. They “showed off” a dual-tone Triber with AMT automatic. Then, there was the Electric Kwid (K-ZE), which will go on sale by late 2021 or early in 2022. Frankly, the Kwid electric was the only exciting and relevant car at Renault’s expo stall. There were the expensive ZOE electric hatchback and Twizy single-seater electric car also on display. But, neither of those two are slated to go on sale in India in the foreseeable future. Besides the concepts, Renault also had a Duster facelift on display, which I almost missed.

Renault Kwid Electric (K-ZE)

What Renault really needed was the second-generation Duster, which has been available internationally since 2017. And to further lift the spirits of the visitors, a production-ready version of the Triber-based subcompact SUV, along with the rumored subcompact sedan in concept form would’ve made the trip to the auto show worth it.








Winners at 2020 Auto Expo – The Motor Show

The Indian Auto Expo is conducted every 2 years and has been platform for the OEMs to showcase their portfolio that could be launched in the Indian market. The Indian Auto Expo is Asia’s biggest Automobile Show and the current edition is 15th in the series. The 2020 Auto Expo has been jointly organized by the SIAM – Society of Indian Automobile Manufacturers, CII – Confederation of Indian Industry and ACMA – Automotive Component Manufacturers Association of India.

We have consolidated the list of Winner OEMs that will make an impact basis the concepts/upcoming vehicles shown at the expo –

  1. Kia Motors:

At the 2018 Expo, Kia was still trying to figure out what excites us (besides an SUV.) Now, they know it very well. So, the products on display were as mass-market as they get without diluting the brand.

The Kia Carnival looks like another brilliant shot at a segment, left unattended by any carmaker in India. It starts where the Innova Crysta tops out. Even if you are considering the Rs. 20.0 lakh version of the Crysta, there’s no reason for not considering one of the lower variants of the Carnival. And, if you want luxury, there’s the Limo variant with ottoman for second-row occupants. This is a car that’ll easily do 500 units every month for the next 2 years or so. Kia needs to be ready to do 1000 units a month should the demand to improve.

Kia Sonet
Kia Sonet

The other car worth noting is the Sonet. It will be the first car capable of receiving over-the-air software updates thus eliminating the need to visit the service centre for software tweaks. It saves time and money for both, the dealers and the customers.

There were also 2 electric cars – Soul and Niro. Both had stickers advertising their driving range of 450km on a single charge. It’s difficult to understand how the Soul with a 30kWh battery can match the 450km range of the Niro, which has a 64kWh battery pack. They’re both decent-looking, nonetheless. The boxy Soul has a stronger SUV vibe than the Niro, but it could do better with slightly higher ground clearance. What’s nice is that it’s based on the Kona’s platform. So, bringing it to market should not take a long time if the segment shows signs of picking up speed.
The Xceed and Stonic crossovers will allow Kia to see how the potential buyers react to these cars at the auto show.



2. Tata Motors 

Unlike the other Indian carmaker, Tata has evolved significantly in recent years and their ability to go-to-market on short notice is commendable. Tata moved quickly to bring a sub-compact SUV Nexon to the market, they soon followed it up with the Harrier to capture the upper end of the SUV market, they updated the Nexon and have a well-priced electric version too to capture the electric SUV trend and now they intend to capture a substantial share of the premium hatchback segment ruled entirely by just 2 cars. The Altroz Electric showcased at the Expo keeps the doors open for a (slightly) affordable electric car from Tata if the Nexon EV and Altroz gain momentum.

Tata HBX
Tata HBX

The rugged HBX concept aims to bring the SUV form factor to the masses with an even more affordable price tag. Tata just took a page out of the 2-wheeler industry by bringing nostalgia to the Expo in the form of Sierra concept. It features an edge-to-edge glass pane and covers its futuristic footprint with an electric powertrain. With such an exciting lineup, there’s a lot to gaze at at the expo and a lot to look forward to from Tata in the coming years.



3. Morris Garage (MG)

MG also put up a fantastic show with a ton of cars to engage the expo visitors. Besides the Hector and ZS, MG had ZS petrol to soon compete with the Creta and Seltos and the Gloster to challenge the Fortuner and Endeavour.
MG also had the micro electric E200, Marvel X SUV concept, eMG6 mid-size plug-in hybrid sedan and the MG3 premium hatchback.

MG RC-6

The outrageous (or exciting, depending on how you see it) but very practical and stylish RC 6 sedan/crossover/SUV/coupe/fastback was also present at the Auto Expo. It’s as big as a Toyota Camry and Skoda Superb but stands out more than either of those two cars with an almost 200mm ground clearance. Along with cars like the MG3, eMG6 plug-in hybrid, 360M, G10 and E200, MG covered all the bases in body styles, price points and powertrains.

While it’s certainly exciting to have such a wide variety of cars at the expo for the visitors, it conveys that MG is yet to outline its long-term roadmap. They’re still figuring out what to do next and are not as focussed as Kia.