Independent, Expert EV Reviews & Advice Since 2006

This is the Future: the Tesla Roadster

The Tesla Roadster is a Lotus Elise powered by an electric motor

The Tesla Roadster is, in simple terms, a Lotus Elise powered by an electric motor. It’s a brand new car brought to you by a team of American dot com millionaires and billionaires who are now focusing their energies on green cars. They stand for a love of cars and driving, combined with an awareness that we need to protect our environment. In other words, this is a vision very much shared by us at Green Car Guide

The car is fast (with a top speed of over 130mph, and 0-60mph in 4 seconds), it has a large range (250 miles), it produces zero/minimal emissions and delivers the equivalent of 135 miles per gallon. It’s also fun to drive and looks cool. Sounds perfect? Well so far it is. There’s only one problem as far as we can see. Although it’s being produced and assembled in the UK, at the moment there are no plans to make it available here. Oh, and it’s not quite available in the U.S. yet either, and when it is, it’s perceived to be expensive, at around $100,000. We say that for such a groundbreaking car, that’s a bargain!

About Tesla Motors

The team and investors behind the company have been involved in companies such as PayPal and eBay – in many cases founding then selling them. Co-founder and CEO Martin Eberhard had always been interested in fast, fun cars, but wanted something that was very energy efficient. After finding nothing like that for sale, he was convinced there was an opportunity. Martin & Marc Tarpenning started Tesla Motors to develop fast, fun, efficient electric cars that people would love to drive.

The entire team at Tesla seem to combine building hi-tech companies with a passion for the environment (the company is named after Nikola Tesla, an inventor, electrical engineer, and scientist – among his life‘s many inventions, and over 700 patents, are the induction motor and alternating-current power transmission).

They see the real difference lying in the intent of the designers. “For the most part, electric cars have been designed by people who believed we should not drive, and, if we must, then we should drive a bare-bones electric car. In sharp contrast, the Tesla Roadster is a driver‘s car: optimized for performance and handling, beautiful in every detail. Tesla Motors celebrates driving.”

Whether people are more concerned about global warming or about national security, they also view America’s dependence on oil as dangerous and costly. 58% of oil in the US comes from other countries, so they say that it‘s practically inevitable that America’s foreign policy principles will be held ransom by its need to maintain domestic economic stability. 68% of the US’s oil is used for transportation, so Tesla believe gasoline-free cars are an ideal solution to these issues.

Tesla view past electric cars as being “designed by people who thought we really shouldn‘t be driving at all – but if we must, we should suffer every minute of it. Electric cars have had terrible range and embarrassing styling. To those who say electric cars have been tried and failed we say, of course electric cars won‘t catch on if no one actually wants to drive them.”

So the company needed to change perceptions of electric vehicles in a big way. To make electric cars a viable alternative, they set out to build one that was looked great and was great to drive.

The Tesla Roadster, is a no-compromise driver‘s car that can accelerate faster than a Porsche 911 and hit a top speed of nearly twice what the law permits. With a range of 250 miles on a single charge, it can be used all day long without worrying about running out of power.

The Tesla Roadster is only the start – the next car to be developed by the company will be more of a family saloon .

Electric Power

Tesla view most electric vehicles as operating under the assumption that driving is merely a necessary evil if you need to get someplace you can’t reach on foot or bike. The result has been cars that are designed, built, and marketed in ways that refuse to glorify driving.

As you can imagine, Tesla has a different view. They see driving as exhilarating. They also see electric cars as equalling freedom – not simply from oil reliance, but from dependence on any specific power source. Electric power can be generated from natural gas, coal, solar, wind, hydro, and nuclear sources — or a combination of all of them — without changing the design of the car.

The Tesla Roadster delivers full availability of performance all the time – its peak torque begins at zero rpm and stays powerful beyond 13,000 rpm. This is the precise opposite of petrol engines, which have very little torque at low rpm and only reach peak torque in a narrow rpm range, which requires frequent gear changes to maintain optimal torque. The Tesla Roadster delivers great acceleration and the highest energy efficiency at the same time. This makes the Tesla Roadster six times as efficient as the best sports cars while producing one-tenth of the pollution.

How It Works

The Tesla Roadster powertrain consists of four main parts:
• The battery pack (the Energy Storage System or ESS)
• Motor
• Transmission
• PEM (Power Electronics Module).

Energy Storage System (ESS)

The biggest challenge of building a high-performance electric car is its battery. It’s heavy, expensive, and offers limited power and range – but it’s clean.

The Tesla Roadster’s battery weighs in at about 1,000 pounds and delivers four to five times the energy-density stores of other batteries. Safe, light, durable, and recyclable, it represents the biggest innovation in the Tesla Roadster and is one of the largest and most advanced lithium-ion battery packs in the world. This gives an excellent range of 250 miles, with excellent performance.

The system uses commodity lithium ion cells which, thanks to high demand by the consumer electronics industry, has spurred development that drives costs down and performance up. Recharge time is also very quick, enabled by an onboard, high-power charging system.


The motor for a high-performance electric car requires a device that is simultaneously light, compact, and high in efficiency.

The power of the motor is not only limited by how much power you put into it, but also by how fast it can be cooled, how hot it can operate, and how efficiently it runs.

Tesla has addressed each of these areas in innovative ways. Their motor can operate continuously around 120°C due to the array of air-cooling fins on the aluminium housing.

Without proper efficiency, the motor would convert electrical energy into heat instead of rotational energy.


The Tesla Roadster has only two forward gears and either one will work for most of your driving. This helps to maximize acceleration, while also allowing a reasonably high top speed. First gear gets you from zero to sixty in about 4 seconds, while second gear takes you to above 130 mph.

Unlike a manual transmission, the car will not stall if it’s in the wrong gear. Because there’s no clutch, you can quickly and easily start from a stop or shift gears on the move.

First gear has strong ‘regenerative braking’ that recharges the battery during deceleration and feels like engine braking in low gear on other sports cars. Second gear has less regenerative braking, and feels like third or fourth gear on other sports cars. The Tesla Roadster needs only two gears because the motor delivers high torque over a much wider range of rpm than any petrol engine. No reverse gear is needed; the motor runs backwards for reversing.

You can drive entirely in second gear – acceleration even in second gear is remarkably fast.

Because it has no clutch and a very wide, flat torque curve, the acceleration of the Tesla Roadster is instantaneous no matter what speed you are driving, no matter what gear you are in.

Power Electronics Module (PEM)

The PEM performs several critical functions in the Tesla Roadster, including motor torque control, regenerative braking control, and charging.

When you shift gears or accelerate, the PEM translates your commands into precisely timed voltages that tell the propulsion motor to respond with the proper speed and direction of rotation.

During normal operation, the PEM monitors aspects such as the voltage delivered by the ESS, the speed of rotation of the propulsion motor, and temperatures of the motor and power electronics. The on-board Vehicle Display System provides information about all of these elements.

Production by Lotus in the UK

Lotus Cars is assembling the Tesla Roadster under contract to Tesla Motors, and Tesla has also hired Lotus Engineering for certain design and engineering tasks. The Tesla Roadster style was developed in Lotus Engineering’s design studio – Lotus Engineering won a design contest where several design firms submitted proposals. Lotus Engineering supplied the initial chassis which was significantly modified by Tesla Motors engineers.

Lotus was chosen as the company is the acknowledged leader worldwide for efficient assembly of sports cars at modest volumes.

A Solar Powered Car

The car can even run on solar power! Tesla Motors can arrange installation of solar panels on an owners home or owners can purchase electricity that has been created by the company’s large scale solar farm partners. This pollution-free electricity is fed into the grid and directly offsets the electricity used to charge the car. This is obviously only in the US market!


The only servicing that’s needed for the first 100,000 miles is for brakes and tyres – this must be one of the longest service intervals of any car on the planet!


The Tesla Roadster cars will be available for purchase in early 2007 with an anticipated delivery date of fall 2007 – again, in the US only.