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Tesla Roadster
ManufacturerTesla Motors
Also calledCode name: DarkStar [1]
AssemblyLotus factory in Hethel, England
Body style(s)2-door Roadster
LayoutRear Mid-engine, Rear-wheel drive
PlatformUnique, developed from Lotus Elise
Engine(s)3-phase, 4-pole AC induction motor
Transmission(s)Single speed BorgWarner fixed gear
Wheelbase1,127 mm (44.4 in)
Length3,946 mm (155.4 in)
Width1,873 mm (73.7 in)
Height1,127 mm (44.4 in)
Fuel capacity53 kW·h (Li-ion battery)
Electric range244 mi (393 km)
RelatedLotus Elise, Tesla Model S

The Tesla Roadster is an all-electric sports car produced by the electric car firm Tesla Motors and is the first car produced by the company.

The Roadster can travel 244 miles (393 km) on a single charge of its lithium-ion battery pack, and can accelerate from 0–60 mph (0–97 km/h) in 3.9 seconds. An improved, Sport version of the Roadster has been released with adjustable dampers and a new hand-wound motor, capable of 0–60 mph (0–97 km/h) in 3.7 seconds. The Roadster's efficiency, as of September 2008[update], was reported as 120 mpgge (2.0 L/100 km).[2][3][4][5] It uses 135 W·h/km (4.60 mi/kW·h), battery-to-wheel, and has an efficiency of 90% on average.

The Roadster was developed with design help from Lotus Cars, who supplied the basic chassis development technology from the Lotus Elise. First unveiled to the public on 19 July 2006, series production of the car began on 17 March 2008.


The car was officially unveiled to the public on July 19, 2006, in Santa Monica, California, at a 350-person invitation-only event held in Barker Hangar at Santa Monica Airport.

The San Francisco International Auto Show, held on November 18–26, 2006, was the Tesla Roadster's first auto show.


The Roadster was developed by Tesla Motors with design help from Lotus Cars in certain areas. Lotus supplied the basic chassis development technology from its Lotus Elise, with which the Tesla engineers designed a new chassis. Barney Hatt at Lotus's design studio developed the styling with input from Tesla. Tesla's designers chose to construct the body panels using resin transfer molded carbon fiber composite to minimize weight; this choice makes the Roadster one of the least expensive cars with an entirely carbon fiber skin.

The AC motor and drivetrain technology are more advanced versions of those used in the GM EV1 and AC Propulsion tzero. Tesla Motors licensed AC Propulsion's EV Power System design and Reductive Charging patent which covers integration of the charging electronics with the inverter, thus reducing mass, complexity, and cost. Tesla Motors then designed and built its own power electronics, motor, and other drivetrain components that incorporate this licensed technology from AC Propulsion.

Several prototypes of the Tesla Roadster were produced from 2004 through 2007. Initial studies were done in two "mule" vehicles. Ten Engineering Prototypes (EP1 thru EP10) which led to many minor changes were then built and tested in late 2006 and early 2007. Tesla then produced at least 26 Validation Prototypes (VP1 thru VP26) which were delivered beginning in March, 2007. These final revisions were endurance and crash tested in preparation for series production.

In January, 2008, the NHTSA announced that it would grant a waiver of the advanced air bag rule noting that the Tesla Roadster already includes standard air bags; similar waivers have been granted to many other small volume manufacturers as well, including Lotus, Ferrari, and Bugatti.


InteriorThe car is assembled at the Lotus factory in Hethel, England, with drivetrain components and body components supplied to the factory by Tesla.[14][15][16]

The Roadster shares less than 10% of its components with the Lotus Elise; shared components are confined to the windshield, air bags, tires, some dashboard parts, and suspension components. The parts supply chain extends around the world; Tesla Motor's plant in Taiwan manufactures the motors and the Energy Storage Systems (ESS) was initially manufactured in Thailand during development and then moved to San Carlos, California, after production started. Chassis are manufactured in Norway. SOTIRA, in St. Meloir & Pouancé, France, create the RTM carbon fiber body panels. The Roadster's brakes and airbags are made by Siemens in Germany and crash testing was conducted at Siemens as well.[3][14][17][18][19][20]

Production delivery was originally planned for October, 2007, and then delayed in September, 2007, until the first calendar quarter of 2008. Series production of the car began on March 17, 2008[21] after over two years of prototyping and testing. However, the first production Roadster, referred to as "P1", was delivered to Tesla Motors' Chairman Elon Musk on February 1, 2008. [22][23][24][25]

Subsequent to completion of production car number one at Hethel, the company announced problems with transmission reliability. The development transmission, with first gear enabled to accelerate 0–60 mph in 4 seconds, was reported to have a life expectancy of as low as only a few thousand miles. Tesla Motors' first two transmission suppliers were unable to produce transmissions, in quantity, that could withstand the gear-shift requirements of the high torque, high rpm electric motor. In December, 2007, Tesla Motors announced plans to ship the initial Roadsters with the transmissions locked into second gear to provide 0–60 mph acceleration in 5.7 seconds. The first production car was not delivered with this interim solution; P1 has both transmission gears enabled. According to the plan, the initial transmissions will be swapped out under warranty when the finalized transmission, power electronics module (PEM), and cooling system becomes available. The EPA range of the car was also restated from 245 miles (394 km) down to 221 miles (356 km). The downward revision was attributed to an error in equipment calibration at the laboratory that conducted the original test.[3][26][27]

Development of productionEdit

During the first two months of production, Tesla produced a total of three Roadsters (P3/VINF002, P4/VINF004, and P5/VINF005). Production car # 1 (P1) and P2 were built prior to the start of regular series production, which began March 17, 2008.[28] By September 10, 2008, Tesla had delivered 27 of the cars to customers. It was also reported that a newer, better transmission had been developed and that production of the car was hoped to reach 20 per week by December, 2008, and 40 per week by March, 2009.[29] Over the next 20 days, however, only 3 more cars had been delivered to customers which brought the total to 30 as of September 30, 2008.[30] By November 19, 2008, more than 70 of the cars had been delivered to customers.[31] By December 9, 2008, the 100th car had been delivered to its customer.[32] By February 11, 2009, 200 Roadsters had been produced. [33] By April 2, 2009, 320 Roadsters had been delivered.[34]


Tesla's "Signature One Hundred" initial set of fully equipped cars sold out by late August, 2006. Tesla Motors then began accepting reservation orders by September, 2006 for their 2008 models, with several payment options available to determine the 2008 delivery date of the vehicle. The second hundred had been reserved by October. As of January 15, 2008, all 650 Tesla Roadsters planned for model year 2008 had been reserved. As it was initially only available in the USA, where traffic stays to the right-hand side of the road (RHT), Roadsters are available only with the steering-wheel on the left-hand side (LHD).

Final pricing for the 2008 Tesla Roadster base model was US$98,000, plus a destination charge of $950. The majority of the first 200 Roadsters ordered by October, 2006, came fully loaded with all optional equipment at a cost of about US$100,000.[35]

For 2009, Tesla plans to deliver 1500 cars.[36] The price for the 2009 models has been increased to US$109,000; options ranging from colors to audio to heavy duty cables can add another $10,000[35]

By February 2009 Tesla had reached an agreement to open stores in Chicago, and was close to finalizing locations in Miami, New York, and Seattle. [33]

Outside the United StatesEdit

The company plans to begin sales in Europe during the third quarter of 2008, initially limited to 250 cars, at just under €100,000 each.[37] The cars will not initially go on sale in the United Kingdom, where traffic stays to the left-hand side of the road (LHT), as there are no plans to build a Roadsters with the steering-wheel on the right-hand side (RHD).

The 2009 Signature Edition Tesla Roadster became available in Europe on August 21, 2008. Only 250 cars are available, at 99,000 Euro. Reservations for the 2010 Roadster are available for a 3,000 Euro refundable reservation fee.[38][39]

In 2009-03-03, Tesla Motors Inc. began selling cars to Canadian customers, with delivery set to begin in 2009 Q4.[40]


Rear view of the vehicleThe first Tesla Motors service center, in Los Angeles, CA, was opened on Santa Monica Boulevard on May 1, 2008.[41]

Tesla Motors publicly opened their second showroom and service area in Menlo Park, CA on July 22, 2008. The Menlo Park location will also be the final assembly area for Tesla Roadsters.

Additional service centers for the Tesla Roadster are planned for New York, NY, Miami, FL, Chicago, IL and Seattle, WA.

Tesla Motors has stated that it will build additional service centers over the next few years to support sales of its next vehicle, the sports sedan currently codenamed the Tesla WhiteStar. "To do 10,000 units for WhiteStar, we need to be in a lot more places," said Darryl Siry, vice president of Marketing.

Planning is underway for an additional 15 service centers in United States major metropolitan locations.[42] Possible locations for sales and service locations in Europe were announced in a letter to customers in May, 2008.

A Roadster purchased in the United States but more than 100 mi (160 km). from the nearest service center was originally announced as requiring an additional US$8,000 out-of-service-area fee; this fee was removed at the start of production and replaced with a policy that customers will be responsible for transporting their Roadster to a service center.[43] No "independent" mechanics are authorized or certified to perform maintenance on the drive train or electrical systems of the Roadster.[15]



The roadster is powered by a 3-phase, 4-pole electric motor, producing a maximum net power of 248 hp (185 kW).[44] The Sport Model introduced during the 2009 Detroit Auto Show includes a motor with a higher density, hand-wound stator that produces a maximum of 288 hp (215 kW).[45] Both motors are designed for rotational speeds of up to 14,000 rpm, and the regular motor delivers an efficiency of typically 90%, or 80% at peak power.


Starting in September, 2008 Tesla Motors selected BorgWarner to manufacture gearboxes and began equipping all Roadsters with a single speed, fixed gear gearbox (8.2752:1) with an electrically-actuated parking lock mechanism and a mechanical lubrication pump.[5]

The company previously worked with several companies, including XTrac and Magna International, to find the right automatic transmission, but a two-gear solution proved to be too challenging. This led to substantial delays in production. At the "Town Hall Meeting" with owners in December, 2007, Tesla announced plans to ship the initial 2008 Roadsters with their interim Magna transmissions locked into second gear limiting the performance of the car to less than what was originally stated (0-60mph in 5.7 seconds instead of the announced 4.0 seconds). Tesla also announced it would upgrade those transmissions under warranty when the final transmission became available.[3][27][46] At the "Town Hall Meeting" with owners on January 30, 2008, Tesla Motors described the planned transmission upgrade as a single-speed gearbox with a drive ratio of 8.27:1 combined with improved electronics and motor cooling that retain the acceleration from 0–60 mph in under 4 seconds and an improved motor limit of 14,000 rpm to retain the 125 mph (201 km/h) top speed.[47] The upgraded system also improved the maximum torque from 200 ft·lbf (270 N·m) to 280 ft·lbf (380 N·m) and improves the Roadster's quarter mile times.


The Roadster's 0–60 mph (0–97 km/h) acceleration time is 3.9 seconds for the Standard Model and 3.7 seconds for the 2009 Sport Model. Some prototypes and early production 2008 Roadsters were limited to 5.7 seconds.[3] The top speed is electronically limited to 125 mph (201 km/h). The Roadster covers the quarter-mile drag strip in 12.757 seconds at 104.74 mph (168.56 km/h).[48]

The EPA combined range (specifying distance traveled between charges) measured in February 2008 for early production Roadsters was 231 mi (372 km) city, 224 mi (360 km) highway, and 227 mi (365 km) combined (city/highway).[49] In August 2008, additional testing with the newer Powertrain 1.5 resulted in an EPA combined range of 244 mi (393 km).[5] It weighs about 2,700 lb (1,200 kg) and is rear wheel drive; most of the car's weight is centered in front of the rear axle. Its body style and smooth underbody result in a Cd of 0.35.[50]

Battery systemEdit

Hooked up power supply.Tesla Motors refers to the Roadster's battery pack as the Energy Storage System or ESS. The ESS contains 6,831 lithium ion cells arranged into 11 "sheets" connected in series; each sheet contains 9 "bricks" connected in series; each "brick" contains 69 cells connected in parallel (11S 9S 69P). The cells are 18 mm (0.71 in) in diameter and 65 mm (2.6 in) long (18650 form-factor); this type of lithium-ion cell is also found in most laptop computer batteries.The pack is designed to prevent catastrophic cell failures from propagating to adjacent cells, even when the cooling system is off. Coolant is pumped continuously through the ESS both when the car is running and when the car is turned off if the pack retains more than a 90% charge. The coolant pump draws 146 watts.[51][52][53][10][54][55]

A full recharge of the battery system requires 3½ hours using the High Power Connector which supplies 70 amp, 240 volt electricity; in practice, recharge cycles usually start from a partially charged state and require less time. A fully charged ESS stores approximately 53 kWh of electrical energy at a nominal 375 volts and weighs 992 lb (450 kg). [56]

Tesla Motors stated in February 2009 that the current replacement cost of the ESS is slightly under USD$36,000, with an expected life span of 7 years/100,000 mi (160,000 km), and began offering owners an option to pre-purchase a battery replacement for USD$12,000 today with the replacement to be delivered after seven years. The ESS is expected to retain 70% capacity after 5 years and 50,000 miles (80,000 km) of driving (10,000 miles (16,000 km) driven each year). Tesla Motors provides a 3 year/36,000 mile warranty on the Roadster with an optional 4 year/50,000 mile extended warranty available at an "additional cost" (2008 Roadster buyers received the 4/50 extension at no cost while later purchasers need to pay). A non-ESS warranty extension is available for USD$5,000 and adds another 3/36 to the coverage of components, excluding the ESS, for a total of 6 years/72,000 mi (120,000 km).[15][57][58][58]

Tesla Motors announced plans to sell the battery system to TH!NK and possibly others through its Tesla Energy Group division. The TH!NK plans were put on hold by interim CEO Michael Marks in September, 2007. [59][60][61]

Energy efficiencyEdit

Evolution of the Roadster's plug-to-wheel efficiency (smaller values indicate better efficiency).In June, 2006, Tesla Motors reported the Roadster's battery-to-wheel efficiency as 110 W·h/km (5.65 mi/kW·h) on an unspecified driving cycle (either a constant 60 mph (97 km/h) or SAE J1634 test) and stated a charging efficiency of 86% for an overall plug-to-wheel efficiency of 128 W·h/km (4.85 mi/kW·h).[62][63]

In March 2007, Tesla Motors reported the Roadster's efficiency on the EPA highway cycle as "135 mpg [U.S.] equivalent, per the conversion rate used by the EPA" or 133 W·h/km (4.66 mi/kW·h) battery-to-wheel and 155 W·h/km (4.00 mi/kW·h) plug-to-wheel.[64][65][66][67]

In August, 2007, Tesla Motors' dynamometer testing of a Validation Prototype on the EPA combined cycle yielded a range of 221 mi (356 km) using 149 W·h/km (4.17 mi/kW·h) battery-to-wheel and 209 Wh/km (2.98 mi/kW·h) plug-to-wheel.[15][68]

In February, 2008, Tesla Motors reported improved plug-to-wheel efficiency after testing a Validation Prototype car at an EPA-certified location. Those tests yielded a range of 220 mi (354 km) and a plug-to-wheel efficiency of 256 mpgge, or 199 W·h/km (3.12 mi/kW·h).[69]

In August, 2008, Tesla Motors reported on testing with the new, single-speed gearbox and upgraded electronics of Powertrain 1.5 which yielded an EPA range of 244 mi (393 km) and an EPA combined cycle, plug-to-wheel efficiency of 28kW·h/100mi (174 W·h/km, 3.57 mi/kW·h).[4]

The Roadster's motor efficiency, battery-to-wheel, is 90% on average and 80% at peak power.[70] For comparison, internal combustion engines have a tank-to-wheel efficiency of about 15%.[71]

Petroleum-equivalent efficiencyEdit

See also: Electric car: Comparison with internal combustion vehicles (ICEVs) The Roadster does not actually use gasoline; therefore, petroleum-equivalent efficiency (mpg, l/100 km) cannot be measured directly but instead is calculated using one of several different methods:

A number comparable to the typical Monroney sticker's "pump-to-wheel" fuel efficiency can be calculated based on regulations from the DOE and its energy content for a U.S. gallon of gasoline of 33,705 W·h/gal (also called the Lower Heating Value (LHV) of gasoline):[72]

For CAFE regulatory purposes, the DOE's full petroleum-equivalency equation combines the primary energy efficiencies of the USA electric grid and the well-to-pump path with a "fuel content factor" that quantifies conservation and scarcity of fuels in the USA.[72] This combination yields a factor of 82,049 W·h/gal in the above equation and a regulatory fuel efficiency of 293 mpggeCAFE.

Recharging with electricity from the average USA grid, the factor changes to 12,307 W·h/ U.S. gal[72] to remove the "fuel content factor" = 1/0.15 and the above equation yields a full-cycle energy-equivalency of 44.0 mpgge full-cycle. For full-cycle comparisons, the sticker or "pump-to-wheel" value from a gasoline-fueled vehicle must be multiplied by the fuel's "well-to-pump" efficiency; the DOE regulation specifies a "well-to-pump" efficiency of 83% for gasoline.[72] The Prius' sticker 46 miles per US gallon (5.1 L/100 km; 55 mpg-imp), for example, converts to a full-cycle energy-equivalent of 38.2 mpgfull-cycle.[72]

Recharging with electricity generated by newer, 58% efficiency CCGT power plants,[73] changes the factor to 21,763 Wh/gal[72] in the above equation and yields a fuel efficiency of 77.7 mpgge.

Recharging with non-fossil fuel electricity sources such as hydroelectric, solar power, wind or nuclear, the petroleum equivalent efficiency can be even higher as fossil fuel is not directly used in refueling.[74]

Monetary cost offers another way to find an equivalent fuel efficiency. Tesla Motors reports an energy cost of approximately US$0.01/mile using PG&E's E-9 night-time incentive charging, or about US$0.03/mile using the retail price of US$0.12/kW·h. Comparison with a gasoline price of US$3.50/ U.S. gallon, for instance, results in an equivalent of 350 mpgge using E-9 or 117 mpgge using retail pricing.


In a November 27, 2006, review of the Tesla Roadster in Slate, Paul Boutin wrote, "A week ago, I went for a spin in the fastest, most fun car I've ever ridden in—and that includes the Aston Martin I tried to buy once. I was so excited, in fact, that I decided to take a few days to calm down before writing about it. Well, my waiting period is over, I'm thinking rationally, and I'm still unbelievably stoked about the Tesla." [75]

In a July 8, 2007 review of the Tesla Roadster, Jay Leno wrote, "If you like sports cars and you want to be green, this is the only way to go. The Tesla is a car that you can live with, drive and enjoy as a sports car. I had a brief drive in the car and it was quite impressive. This is an electric car that is fun to drive." [76]

In a March, 2008, article, Car and Driver had this to say about the Tesla Roadster: "Highs: Intoxicating midrange powertrain response, user-friendly operation, realistic range; Lows: expensive for performance, iffy shifter, unknown reliability and life cycle, The Verdict: if we wanted an electric car, we’d be happy to live with this one". [55]

Motor Trend gave a generally favorable review, stating that, it was "undeniably, unbelievably efficient" and would be "profoundly humbling to just about any rumbling Ferrari or Porsche that makes the mistake of pulling up next to a silent, 105-mpg Tesla Roadster at a stoplight."; however, they detected a "nasty drivetrain buck" during the test drive of an early Roadster with the older, two-speed transmission.[77]

AutoWeek reported that while "the roadster has had a few transmission troubles [...] Tesla Roadster buyers will enjoy their energy-efficient mounts. We know we did."[78]

Road and Track said "The Tesla feels composed and competent at speed with great turn-in and transitioning response", though they recommended against it as a "primary grocery-getter".[79] Later, in February 2009, Road and Track tested a production vehicle, and independently confirmed what they called "extravagant claims", that the Roadster had a 4.0 s 0-60 mph acceleration and a 200-mile range. They said the Roadster felt like "an over-ballasted Lotus Elise", but that the weight was well-distributed, so the car remained responsive. "Fit and finish of our Tesla were exemplary", which Road and Track thought fit the target market. Overall, they considered it a "delight" to drive.[80]

Top Gear's Jeremy Clarkson reviewed the Tesla Roadster with the v1.5 transmission and described the driving experience with the exclamations "God almighty!", "Wave goodbye to the world of dial-up, and say hello to the world of broadband motoring!" and "This car is Biblically quick!" when comparing the acceleration versus a Lotus Elise. Halfway through the review, however, Clarkson simulated the experience one might get when the charge falls below the safe level but failed to explain during the programme that the failure was merely a simulation.[81] The Top Gear team calculated that their extremely demanding driving (which Top Gear is famous for putting cars through) would deplete the charge after 53 miles.

The second Tesla roadster reviewed experienced overheating and thus also reduced its power output. The car was shown parked, however, thermal limits only reduce the maximum speed by 16% to 105 mph (169 km/h).[82] Before they could bring the first Tesla roadster out, a "brake failure" had to be fixed. The "brake failure" turned out to be a blown fuse which affected the auto-assist braking feature and not the ability of the car to be stopped. Despite Tesla's conviction that the car was up and running in no time, Clarkson rebuffed saying "Nobody gives a flying **** how the brakes failed. Whether it was a blown fuse or not, they were still not working." [81] Clarkson ended the televised review with the phrase "What we have here then is an astonishing achievement. The first electric car you would actually want to buy. It's just a shame then that in the real world, it doesn't seem to work."


INDEX - INDEX Award 2007[83] BusinessWeek - Best Product Design of 2007, Ecodesign[84] Forbes - Best Cars 2006: New car that best lived up to the Hype[85] Time - Best Inventions 2008 - Transportation Invention[86] Time - Best Inventions 2006 - Transportation Invention[87] Popular Mechanics - Breakthrough Awards 2006[88] Global Green USA - Product/Industrial Design[89][90] CarDomain - People's Choice: Most Exciting 2007 Car Launch [91] 2009 Best Green Exotic, duPont REGISTRY[92]

External linksEdit


On Top GearEdit


"Performance Specs - 2008 Model Year". "The Tesla Roadster Battery System" (PDF). white papers and presentation Retrieved from "" Categories: Electric sports cars | Production electric vehicles | Sports cars | Alternative propulsion | Rear wheel drive vehicles | Vehicles introduced in 2007 | Roadsters | Mid-engined vehicles | Battery electric vehicles Hidden categories: Articles containing potentially dated statements from September 2008 | All articles containing potentially dated statements

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