So, wassapening? Long time since I posted here. I mean a really long time. It’s been dormant longer than the Yellowstone volcano. When that awakens, it’s going to mean mass extinction. But I hope the rebirth of this blog doesn’t imply the same!
I just read an article about electric vehicles and their future prospects and felt compelled to write my thoughts on the subject. This is one topic I am and have been passionate about for a long time. The feel of a motor quietly whirring away at thousands of RPM and providing mountains of torque from a standstill seems to entice me.
What exactly defines an electric vehicle? A power source and a motor are the basic components which are enough to turn an immobile piece of plastic and metal into a humming people mover. But to sustain-ably keep it in motion requires many more.
Batteries are the main hindrance to making an effective electric vehicle. Even though motor technology has progressed significantly, battery technology has moved at a snails pace. Batteries that compete with the energy storage capacity of fossil fuels are expensive. For example, petrol is more compact and one tank of it can fuel a vehicle for hundreds of kilometres. But replace that same tank volume with batteries and to expect the same kind of range, one will have to invest in expensive lithium polymer batteries.
These will also lead to an increase in weight, and lead to problems with the vehicles handling. The Tesla roadster is a prime example. Its chassis is derived from the Lotus Elise, which handles like a bat out of hell. Its one of the best handling cars according to many. But the Tesla has very sluggish handling and can never compete with its brother from another power. All this is due to the structural modifications which had to be made to accomodate the electrical drive system.
Another hindrance when it comes to batteries is their recharging capability. It takes hours to rechagrge even the best of batteries, with high current charger. On the other hand to fill an empty tank full of fuel takes only minutes and your set for another 200-300kms atleast. So in the case of electric cars, you need to plan your day otherwise you risk being stranded. This has lead to the term range anxiety becoming common lingo among owners of electric vehicles. The Reva for example (the vilified GWiz in the UK), originally had a range of only 80km before it became an expensive paperweight.
There have been attempts to remedy this problem by making batteries swappable and having quick charge stations along highways. Another system is the vanadium redox battery where the electrolyte is the main power source. When its depleted, its pumped out and replaced with a fresh batch and you’re ready to go. But the high costs involved have stalled its employment.
The high voltages involved are also a cause for concern. The spate of fires involving the quite recently released Fisker Karma are proof of that. Extensive insulation is required to prevent shorts in the battery components of these vehicles. There have been cases of coolant leaks that lead to battery shorts. In one incident, a leak in a Karma destroyed a whole house and two other cars.
On the other hand, taking into consideration the mechanical complexity, electric vehicles have only one moving part: the motor. So there is a lesser probability of failure as compared to an internal combustion engine, which has thousands of moving parts. The way that power is transferred to the road also is much simpler. As torque conversion does not require complex gearboxes, clutches etc. it becomes easier for the driver. All one has to worry about are an accelerator and a brake pedal . And power is available instantly as an electric motor provides its maximum torque right from the start. Hence acceleration is much better compared to a conventional vehicle and involves no mucking around with gears. But the maximum speed attainable is significantly lesser. Higher speeds involve making changes to the driving gear but this will lead to a reduction in acceleration.
Due to all these reasons, hybrids have been the way to go. They use dual power systems, conventional IC engines coupled with electric drive systems. They are used in concert or individually as the situation demands. The most successful among these is the Toyota Prius with its Hybrid Synergy Drive.
The drive system seamlessly transitions between electric and gasoline modes as and when required. The driver plays no role in the shift but he can select different modes such as power or efficiency. But the computing power involved is very high and this increases complexity further as the car maker has to think about both electrical and mechanical requirements. Off late, cars like the Nissan Leaf and Chevrolet Volt are trying to push forward the usefulness of all-electric cars.
But one area where electric vehicles are doing very well are the DIY end of the spectrum. Electric power assist systems for bicycles and other human powered vehicles (HPVs) are very attractive as they extend the range. and when you do run out, you’re not completely stranded. These are especially useful for uphill sections. But this does increase the weight significantly and this is very important when it comes to HPVs.
Until now cars have been the prime candidates for electric conversion. But a closer look at the shortcomings stated above make two wheelers a better choice. Range being a limiting factor makes an electric vehicle good for in city runabouts. And for short trips, a smaller vehicle seems like a better idea considering most users travel alone and over distances where the short range of electric vehicles will not be a hindrance. The ease of use and the lesser complexity involved mechanically also makes it better for such uses. The Brammo Enertia is one such commercial electric motorbike, which looks nice and rides great. Its bigger brother, the Empulse is geared more towards the performance end of the spectrum.
Recent startups like Lit Motors and their C-1 are taking a different approach of using cabin motorcycles which drive like a car. Dual gyroscopes are used to keep it steady and advanced electronics help to extend its range.
Like I stated before, DIYers are the forefront of the electric revolution. They might not have the funds of larger corporations, but the penetration is more. Kits for converting bicycles to electric locomotion are extremely common. Some, such as the one shown below, consist of a hub motor and a battery pack, making conversion extremely simple. But this adds to the weight of the bike, so when the power runs out, you have that much more weight to push. Going up a hill is bad enough without the added weight, but with the battery and added rotational inertia added by the hub motor, it becomes nearly impossible. So trips have to be planned to the last detail. But this is considerably cheaper compared to a full blown electric vehicle and gives you the option of propelling it even when the battery is dead.
Hence, electric is the future, irrespective of the method of adoption. But better batteries, faster charging and reduced weight are necessary before the general public will take to it. Until then DIY is god and always will be!