Electric-powered racing

A sporty electric car?

Tesla Roadster power source

Recently great efforts have been made to develop reasonable using conditions for electric cars in Estonia and to promote using them. Now they still have too many disadvantages for being able to replace the usual cars, but this may soon change. By many car manufacturers, only very small and golf-cart-like vehicles are produced as zero-emission cars.

Perhaps only Nissan Leaf reminds a “normal car” the most. Important is the economic value, not power and speed, although Tesla Roadster has already disproved it. A question arises, if one could already build a special electric powered car, which would have an explosive acceleration as the most important characteristics. Could an electric car compete in straight-line acceleration with a huge capacity V8 or high-tuned turbo engines?

At least in the U.S. drag racing with electric cars has long been practiced. Since 1996 there is even a roof organisation for electric-powered racers: National Electric Drag Racing Association (NEDRA). In a quarter mile street class cars have already defeated the 10 seconds limit. Obviously technical rules are different from internal combustion engines – competitors are divided into classes by the size of supply voltage, battery type or engine’s configuration. It may seem that with an electric car, drag racing loses its attraction. There will remain speed and tire smoke, but will be no deafening engine noise and no flames.

Batteries are the basis for everything

The body, chassis and geometry of suspension are analogous to the traditional drag racing cars, because the drag strip as well as the laws of physics remain the same. The difference comes from the power source – where and how to install one or more electric motors and a battery stack. Here comes the main problem – although an electric motor is much easier than an internal combustion engine, heavy batteries must be transported as well.

Fortunately, due to the development of technology, weight of the batteries is decreasing and energy storage is steadily increasing. In the past, traditional heavy acid batteries were used a lot because of their good availability. Unfortunately, in case of high power consumption, they tend to explode. Nowadays there are available such lithium-ion batteries like Tesla Roadster have, which allow a much higher energy density per weight. Originally rather short-aged batteries have been improved continuously and they have already reached durability for tens of years. It is also expected that the technological advances will soon enable us to use super condensers, which are particularly suitable for sudden power surge. Their capacity drops behind the batteries, but they are capable of giving high amperage extremely quickly without damaging itself.

Whip the engine

In drag racing, usually DC electric motor with brushes is used instead of a more effective AC motor like modern city cars have. As we know, the DC electric motor produces maximum torque on rotation speed of 0 rpm. This is why it has more rapid start and faster 60 ft compared to an internal combustion engine or another type electric motor. Of course only in case the wires and power transmission endure. The latter must be much more stronger than the transmission in the equally quick fuel burning competitor. When speed increases, then the torque decreases in proportion, which is why the electric motor also require a gearbox.

In the U.S., for example, WARP engines are used as an accelerating power source. They are often stacked up in series with 2-3 pieces, because smaller motors as well as their controllers are cheaper than a single big one. When in the beginning the supply voltage of an average electric car was around 100 V, then now more powerful cars are built with a supply voltage of around 400 V (batteries in series) and for a moment, a few thousands amps of current are smashed into the engines coils. As the DC motor needs a controller for regulating speed, the liquid-cooled Zilla 2K is made especially for this kind of high amperages. Also the engine itself needs to be cooled, because the brushes and the commutator heat up very quickly.

Inevitably, if consumption is very high, then the batteries are able to give power for a short time only. However, as usual engines that are built especially for drag racing, run full blast only for ten seconds and expensive parts are usually not spent for a cruising in the streets. An electric engine has here a great advantage for both purposes: it is capable of a sudden acceleration as well as driving 150 km at normal speed. Like the street legal record holder White Zombie.

The Black Current