Wednesday, February 16, 2011

Tesla Roadster

Tesla Roadster
Tesla Roadster -- 02-11-2011.jpg
ManufacturerTesla Motors
Also calledCode name: DarkStar
AssemblyHethel, Norfolk, England
Menlo Park, California, USA
Body style(s)2-door Roadster
LayoutRear mid-engine, rear-wheel drive
Engine(s)3-phase 4-pole electric motor
Transmission(s)Single speed BorgWarner fixed gear
Wheelbase2,352 mm (92.6 in)
Length3,946 mm (155.4 in)
Width1,873 mm (73.7 in)
Height1,127 mm (44.4 in)
Curb weight2,723 lb (1,235 kg)
RelatedLotus Elise
DesignerTesla Motors

The Tesla Roadster is a battery electric vehicle (BEV) sports car produced by the electric car firm Tesla Motors in California. The Roadster was the first highway-capable all-electric vehicle in serial production available in the United States. Tesla had produced more than 1,200 Roadsters sold in at least 28 countries as of July 2010. Tesla began producing right-hand-drive Roadsters in early 2010 for the British Isles, Australia, Japan, Hong Kong and Singapore.
The Roadster is the first production automobile to use lithium-ion battery cells and the first production BEV (all-electric) to travel more than 200 miles (320 km) per charge. The world distance record of 501 km (311 mi) for a production electric car on a single charge was set by a Roadster on October 27, 2009, during the Global Green Challenge in outback Australia, in which it averaged a speed of 25 mph (40 km/h). In March 2010, a Tesla Roadster became the first electric vehicle to win the Monte Carlo Alternative Energy Rally and the first to win any Federation Internationale de l'Automobile-sanctioned championship when a Roadster driven by former Formula One driver Érik Comas beat 96 competitors for range, efficiency and performance in the three-day, nearly 1,000-kilometer (621 mile) challenge.
According to the U.S. EPA, the Roadster can travel 244 miles (393 km) on a single charge[citation needed] of its lithium-ion battery pack, and can accelerate from 0 to 60 mph (0 to 97 km/h) in 3.7 seconds. The Roadster's efficiency, as of September 2008, was reported as 120 mpgge (2.0 L/100 km). It uses 135 Wh/km (21.7 kW·h/100 mi, 13.5 kW·h/100 km or 490 kJ/km) battery-to-wheel, and has an efficiency of 92% on average.
The Roadster has a base price of US$109,000 in the U.S. and a base price of £86,950 in the UK and €84,000 in continental Europe. As an electric vehicle, the Roadster also qualifies for several government incentives in many nations.


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. Tesla Roadsters have been featured in numerous subsequent auto shows, including international shows in Los Angeles, Detroit and Frankfurt.
The first Tesla Roadster was delivered in February 2008 to Tesla co-founder, chairman and product architect Elon Musk. The company produced 500 similar vehicles through June 2009. In July 2009, Tesla began production of its 2010 model-year Roadster—the first major product upgrade since Tesla began production in 2008. Simultaneously, Tesla began producing the Roadster Sport, the first derivative of Tesla's proprietary, patented powertrain. The car accelerates from 0 to 60 mph in 3.7 seconds, compared to 3.9 seconds for the standard Roadster. Changes for the 2010 model-year cars include:
An upgraded interior and push-button gear selector, including "executive interior" of exposed carbon fiber and premium leather, and clear-coat carbon fiber body accents.
Locking, push-button glove box wrapped in leather.
A centrally mounted video display screen to monitor real-time data, including estimated range, power regenerated, and the number of barrels of oil saved. This convenient screen is visible to the driver and passenger.
Adjustable, custom-tuned suspension with the option of sport and comfort settings.
More powerful and immediate heating, ventilation and air-conditioning.
More efficient motor and hand-wound stator. The new motor generates more kilowatts per amp—more mechanical power—than the predecessor.
A suite of sound-deadening measures to dramatically reduce noise, vibration and harshness. For instance, engineers added pellets to a member of the chassis side rail. These pellets expand by 5,000 percent during the adhesive heating cycle to eliminate rattles.
A Roadster running at the Goodwood circuit. The Tesla Roadster is increasingly
popular on circuits throughout Europe, including the UK's Crystal Palace.
Beginning mid-March 2010, Tesla Motors, in an effort to show off the practicality of its electric cars, sent one of its Roadsters around the world. Starting at the Geneva autoshow, the roadster will travel until its arrival at the Paris Autoshow on September 28, 2010.
In July 2010, Tesla introduced the "Roadster 2.5," the latest update of the Roadster. New features in Roadster 2.5 include:
A new look, which includes a new front fascia with diffusing vents, and rear diffuser reflecting the future of Tesla design
Directional forged wheels available in both silver and black
New seats with improved comfort, larger more supportive bolsters and a new lumbar support system
Power control hardware that enables spirited driving in exceptionally hot climates
An optional 7" touchscreen display with back-up camera
Improved interior sound reduction including new front fender liner material make the cabin quieter
The Roadster is the most expensive prize ever offered on The Price Is Right, $112, 845, in a playing of Green Road on April 22, 2010. A Roadster is used as a promotional tool for sustainable energy.


The Roadster was developed by Tesla Motors to mass produce AC Propulsion's tzero concept car. The production idea was conceived by Martin Eberhard and Marc Tarpenning who incorporated Tesla Motors in Delaware on July 1, 2003, to pursue the idea commercially. South African-born entrepreneur Elon Musk took an active role within the company starting in 2004, including investing US$7.5 million, overseeing Roadster product design from the beginning, and greatly expanding Tesla's long-term strategic sales goals to include developing mainstream vehicles after the sports car. Musk became Tesla's Chairman of the Board in April 2004 and had helped recruit JB Straubel as chief technology officer in March 2004. Musk received the Global Green 2006 product design award for the design of the Tesla Roadster, presented by Mikhail Gorbachev, and he received the 2007 Index Design award for the design of the Tesla Roadster.
Before Tesla had developed the Roadster's proprietary powertrain, the company 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 then designed and built its own power electronics, motor, and other drivetrain components that incorporated this licensed technology from AC Propulsion. Given the extensive redevelopment of the vehicle, Tesla Motors no longer licenses any proprietary technology from AC Propulsion. The Roadster's powertrain is unique.
On 11 July 2005, Tesla and British sports car maker Lotus entered an agreement about products and services based on the Lotus Elise, where Lotus provided advice on designing and developing a vehicle as well as producing partly assembled vehicles,[ and amended in 2009. helped with basic chassis development. The Roadster has a parts overlap of roughly 6 percent with the Lotus Elise. 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.
Several prototypes of the Tesla Roadster were produced from 2004 through 2007. Initial studies were done in two "test mule" vehicles based on Lotus Elises equipped with all-electric drive systems. Ten Engineering Prototypes (EP1 through 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 through VP26) which were delivered beginning in March 2007. These final revisions were endurance and crash tested in preparation for series production.
In August 2007, Martin Eberhard was replaced by an interim CEO, Michael Marks. Marks accepted the temporary position while a recruitment drive went into place. In December 2007, Ze'ev Drori became the CEO and President of Tesla Motors. In October 2008, Musk succeeded Ze'ev Drori as CEO. Drori became Vice Chairman and left the company in December. 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. Tesla delivered its first production car in February 2008 to Musk.
Tesla announced in early August 2009 that Roadster sales had resulted in overall corporate profitability for the month of July 2009. The company said it earned approximately US$1 million on revenue of US$20 million. Profitability arose primarily from improved gross margin on the 2010 Roadster, the second iteration of Tesla’s award-winning sports car. Tesla, which like all automakers records revenue when products are delivered, shipped a record 109 vehicles in July and reported a surge in new Roadster purchases.
Tesla, which signed a production contract with Group Lotus in 2007 to produce "gliders" (complete cars minus electric powertrain) for the Roadster, announced in early 2010 that Roadster production would continue until early 2012, in part due to tooling changes at Lotus' assembly plant in the UK.

Interior of Roadster 2.5 from July, 2010.
Tesla cumulative production of the Roadster reached 1,000 cars in January 2010. The Roadster is an American car with a vehicle identification number common to all cars considered American manufactured, but it has parts from around the world. The body panels come from French supplier Sotira. These are sent from France to Hethel, U.K., where Tesla contracts with Lotus to build the Roadster's unique chassis. The Roadster shares roughly 6 percent of its components with the Lotus Elise; shared components include the windshield, air bags, some tires, some dashboard parts, and suspension components. The Roadster's single-speed gearbox is made in Detroit to Tesla's specifications by Auburn Hills, Michigan-based supplier Borg Warner. Brakes and airbags are made by Siemens in Germany, and some crash testing was conducted at Siemens as well.
For Roadsters bound for customers in North America, the chassis is then sent to Menlo Park, California, for final assembly. For Roadsters bound for customers in Europe or elsewhere outside of North America, the chassis is sent to a facility near Hethel, U.K., for final assembly. At these final assembly locations, Tesla employees install the entire powertrain, which consists of the battery pack, power electronics module, gearbox and motor. Tesla also performs rigorous "pre-delivery inspection" on every car before customers take ownership.
On 22 March 2010, Tesla ordered a minimum of 2,400 units from Lotus until 31 December 2011.

History of production
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 to 60 mph (0 to 97 km/h) 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 to 60 mph (0 to 97 km/h) 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 downward from 245 to 221 miles (394 to 356 km). The downward revision was attributed to an error in equipment calibration at the laboratory that conducted the original test.
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.
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. 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.
By November 19, 2008, more than 70 of the cars had been delivered to customers.
By December 9, 2008, the 100th car had been delivered to its customer.
By February 11, 2009, 200 Roadsters had been produced.
By April 2, 2009, 320 Roadsters had been delivered.
In May 2009, Tesla issued a safety recall for all 345 of its Roadsters that were manufactured before April 22, 2009. Tesla sent technicians to customers' homes to tighten the rear, inner hub flange bolts. Tesla Motors told customers that without this adjustment, the driver could lose control of the car and crash. The problem originated at the Lotus assembly line that builds the Roadster and Lotus is also recalling some of its own vehicles. Tesla reminded customers that millions of cars are recalled every year.
By the end of May 2009, the 500th Roadster had been delivered.
Tesla made its first profit ever in July 2009, when it shipped 109 vehicles, the most ever so far for a single month.
By September 15, 2009, 700 Roadsters had been delivered.
Tesla announced on January 13, 2010, that it had produced its 1,000th Roadster. The company has delivered vehicles to customers in 43 states and 21 countries worldwide.[ In 2009 Tesla began taking orders from customers in Canada, and Canadian deliveries began in February 2010.
In January 2010, Tesla began producing its first right-hand-drive Roadsters for the UK and Ireland. The 2010 model-year right-hand-drive Roadster includes a suite of unique noise-reduction materials and an upgraded sound system. The Roadster starts at £86,950 and costs about 1.5p per mile.
On 29 January 2010, in a Form S-1 filing of its preliminary prospectus with the U.S. Securities and Exchange Commission, the company stated that it would halt production of the Roadster in 2011 and replace it with a new model which would not be introduced until 2013 at the earliest: "...we do not plan to sell our current generation Tesla Roadster after 2011 due to planned tooling changes at a supplier for the Tesla Roadster, and we do not currently plan to begin selling our next generation Tesla Roadster until at least one year after the launch of the Model S, which is not expected to be in production until 2012..."
On 16 March 2010, Tesla Motors announced that it had "negotiated agreements with key suppliers that will increase total Roadster production by 40 percent and extend sales into 2012", also indicating that it would expand into the Asian and Australian markets by 2011.
On 2 December 2010, Tesla had delivered more than 1400 Roadsters.


Tesla had delivered more than 1,200 cars to customers in more than 25 countries by July 2010. Tesla CEO, Chairman and Product Architect Elon Musk said in June 2009 that the company would begin producing a right-hand-drive version of the car in 2010. The base price for the 2010 models, which began shipping to customers in July 2009, was US$109,000. The Roadster has a bumper-to-bumper 3-year, 36,000-mile (58,000 km) warranty. Tesla also offers an extended powertrain warranty and a battery replacement warranty. Options ranging from colors to audio to high-power connectors for faster charging will increase the price.
In July 2009, Tesla announced that US consumers could finance the Roadster through Bank of America. Financing is available for up to 75 percent of the total vehicle purchase price. A customer approved for a 5-year financing term on a base Roadster could put down as little as $20,000 before taxes and net of the US federal tax credit. The monthly payment would be approximately $1,700 at a 5 percent annual percentage rate (APR). That monthly payment is typical for high performance, although the Roadster costs roughly $4 to refuel and does not require routine oil changes or exhaust system work. Unlike internal combustion engines, Teslas get a 100 percent waiver on sales, luxury and use taxes in at least four states, and they qualify for commuter lane privileges, free parking and free charging in many regions.
Tesla sells Roadsters directly to customers. It sells online, in 13 showrooms and over toll-free phone lines in North America and Europe. Tesla does not operate through franchise dealerships but operates company-owned stores. The company has said that it takes its retail cues from Apple, Starbucks and other non-automotive retailers.

Outside the United States

A Tesla Roadster in Barcelona.
The company has been shipping cars to European customers since the summer of 2009. Tesla sold out of its EU special-edition vehicle, which had a 2010 model-year production run of 250 cars, with a base price of €99,000.

Tesla opened a showroom in London, its first outside the US, on June 25, 2009, and announced at the same time that it would start building right-hand-drive models from early 2010. Tesla opened a store in Munich in September 2009 and a store in Monaco in November 2009. It opened stores in Zurich and Copenhagen in the summer of 2010. Reservations for the 2010 Roadster are available for a 3,000 Euro refundable reservation fee.

Tesla on display at the 2010 Canadian International Autoshow in Toronto

Rear view of the vehicle


Electric vehicles require much less service and maintenance than internal combustion engine vehicles. They do not require routine oil changes. They do not have any tailpipe emissions and therefore do not require any muffler or exhaust system work. They do not require replacement spark plugs, pistons, hoses or belts. The conventional parts of the car—including the brakes, body work and any interior and HVAC work—can be performed by any qualified automotive technician, exotic car garage or other local provider. 
Tesla recommends that customers bring their car to a service center for an antifreeze change every five to seven years. Tesla's website recommends the owner bring the vehicle in for service "once a year or every 12,000 miles". For other concerns with Tesla's all-electric powertrain, Tesla has created a "mobile service unit" that dispatches company-trained technicians to customers' homes or offices in case the owner is experiencing problems. Tesla charges the customer according to the distance the service unit needs to travel: one US dollar per mile roundtrip with a 100 dollar minimum. Technicians drive company vans equipped with numerous tools and testing equipment to do "in the field" repairs, enhancements and software upgrades. Tesla debuted its "house call" approach in the spring of 2009, when the company announced a recall due to a manufacturing problem in the Lotus assembly plant, which also affected the Lotus Elise and other models from the British sports car maker.
The first Tesla Motors service center, in Los Angeles, California, was opened on Santa Monica Boulevard on May 1, 2008. Tesla Motors publicly opened their second showroom and service area in Menlo Park, California on July 22, 2008. The Menlo Park location is also the final assembly area for Tesla Roadsters. Tesla also operates service centers in New York City, Miami, Florida, Chicago, Illinois and Seattle, Washington.
Tesla plans to build additional service centers over the next few years to support sales of its next vehicle, the Model S sports sedan. Planning is underway for an additional 15 service centers in United States major metropolitan locations. Possible locations for sales and service locations in Europe were announced in a letter to customers in May 2008.


The roadster is powered by a 3-phase, 4-pole electric motor, producing a maximum net power of 248 hp (185 kW). Maximum torque is 200·ft-lbf (270 N·m), obtained at 0 rpm and almost constant up to 6,000 rpm, a common feature of electric motors and one of the biggest differences (from the performance point of view) with internal combustion engines. The motor is air-cooled and does not need a liquid cooling system. 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). 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. It weighs less than 70 pounds (32 kg).

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 pawl mechanism and a mechanical lubrication pump.
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 two-speed direct shift manual transmissions locked into second gear, limiting the performance of the car to less than what was originally stated (0 to 60 mph (0 to 97 km/h) 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. 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 to 60 mph (0 to 97 km/h) in under 4 seconds and an improved motor limit of 14,000 rpm to retain the 125 mph (201 km/h) top speed. The upgraded system also improved the maximum torque from 200 to 280 ft·lbf (270 to 380 N·m) and improves the Roadster's quarter mile times.

Gear selector
In the interior the gear selector is similar to a push-button automatic with buttons labeled P,R,N and D while some earlier models have a gear lever similar to that in cars with manual transmission.

The Roadster's 0 to 60 mph (0–97 km/h) acceleration time is 3.9 seconds for the Standard Model and 3.7 seconds for the 2010 Sport Model. MotorTrend, which performed the first independent instrumented testing of the Roadster Sport, confirmed the company's reported 0 to 60 mph time of 3.7 seconds (MotorTrend recorded 0 to 60 mph of 3.70 seconds; it recorded a quarter-mile test at 12.6 sec @ 102.6 mph). 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). 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.
Tesla began delivering the higher performance Sport version of the Roadster in July 2009. The Roadster Sport has adjustable dampers and a new hand-wound motor, capable of 0 to 60 mph (0 to 97 km/h) in 3.7 seconds. Scotty Pollacheck, a high-performance driver for Killacycle, drove a 2010 Tesla Roadster Sport at the Wayland Invitational Drag Race in Portland, Ore., in July 2009. He did a quarter-mile (~400 m) in dry conditions in 12.643 seconds, setting a new record in the National Electric Drag Racing Association among the SP/A3 class of vehicles.
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). In August 2008, additional testing with the newer Powertrain 1.5 resulted in an EPA combined range of 244 mi (393 km). The vehicle set a new distance record when it completed the 241-mile (388 km) Rallye Monte Carlo d'Energies Alternatives with 36 miles (58 km) left on the charge.
Simon Hackett and Emilis Prelgauskas broke the distance record for an electric vehicle, driving 501 km (311 miles) from Alice Springs to Marla, South Australia, in Simon's Tesla Roadster. The car had about 4.8 km (three miles) of range left when the drive was completed.

Battery system

Connected 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 of the 18650 form-factor commonly found in laptop 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.
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). 
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).
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. Think now obtains their Lithium-Ion batteries from Enerdel.

The Tesla Roadster uses a unique charging connector, although Tesla has indicated they will convert to the SAE J1772 standard. The vehicle can be recharged using:[
a wall-mounted 208–240 volt, 70 amp maximum current Home Connector. This appears to be the TS-70 charging station from ClipperCreek.
a portable 120–240V, 40A maximum current Universal Mobile Connector cable that can plug into a NEMA 14-50 receptacle and other 240V receptacles using adapters.
a portable 120V, 15A maximum current Spare Mobile Connector cable that plugs into a standard North American domestic socket.
Charging times vary depending on the ESS's state-of-charge, the available voltage, and the available circuit breaker amp rating (current). In a best case scenario, Tesla documents a recharge time of just under 4 hours using a 240v charger on a 90 amp circuit breaker and a worst case of 48 hours using a 120v outlet and a 15 amp breaker.

Energy efficiency

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 (17.7 kW·h/100 mi) 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 (20.5 kW·h/100 mi).
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 (21.5 kW·h/100 mi) battery-to-wheel and 155 W·h/km (24.9 kW·h/100 mi) plug-to-wheel.
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 (23.9 kW·h/100 mi) battery-to-wheel and 209 Wh/km (33.6 kW·h/100 mi) plug-to-wheel.
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 (32.1 kW·h/100 mi).
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 174 W·h/km, 630 kJ/km (28 kW·h/100 mi).
The Roadster's motor efficiency, battery-to-wheel, is 92% on average and 85% at peak power. For comparison, internal combustion engines have a tank-to-wheel efficiency of about 15%.

Petroleum-equivalent efficiency
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):

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 the value of conservation, scarcity of fuels, and energy security in the USA. 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⁄galUS 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. 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.
Recharging with electricity generated by newer, 58% efficiency CCGT power plants, changes the factor to 21,763 W·h⁄gal 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.
Monetary cost offers another way to find an equivalent fuel efficiency. Tesla Motors reports an energy cost of approximately US$0.04/mile if using PG&E's night-time incentive charging, available in only 2 U.S. states during the night. Comparison with a gasoline price of US$3.00/ U.S. gallon, for instance, results in an equivalent of 75 mpgge using E-9 or 100 mpgge using retail pricing.


Tesla Roadster reviews can be grouped in two main categories: reviews on cars in serial production (model year 2008–2010) and older reviews of "validation prototypes," typically from 2006–2008, before Tesla began serial production and customer deliveries.
The global online auto review site tested Tesla's fourth-generation car in October 2010. Autoguide editor Derek Kreindler said "The Tesla Roadster 2.5 S is a massively impressive vehicle, more spacecraft than sports car. Theories like global warming, peak oil and rising oil prices should no longer bring heart palpitations to car fans. The Tesla shows just how good zero-emissions “green” technology can be. Quite frankly, getting into a normal car at the end of the test drive was a major letdown. The whirr of the engine, the shove in the backside and the lithe little roadster that seems to pivot around you is replaced by a grunting, belching, feedback-free driving experience." He continues on that "but for a $100,000 car, it could use some work" complaining of purposfully cheap work.
In the March 2010 print edition of British enthusiast magazine EVO (p. 120), editor Richard Meaden was the first to review the all-new right-hand-drive version of the Roadster. He said the car had "serious, instantaneous muscle." "With so much torque from literally no revs the acceleration punch is wholly alien. Away from traffic lights you'd murder anything, be it a 911 Turbo, GT-R or 599, simply because while they have to mess about with balancing revs and clutch, or fiddle with launch controls and invalid warranties, all you have to do is floor the throttle and wave goodbye."
In December 2009, Wall Street Journal editor Joseph White conducted an extended test-drive and determined that "you can have enormous fun within the legal speed limit as you whoosh around unsuspecting Camry drivers, zapping from 40 to 60 miles per hour in two seconds while the startled victims eat your electric dust." White, a Pulitzer Prize-winning journalist, praised the car's environmental efficiency but said consumer demand reflected not the environmental attributes of the car but its performance. "The Tesla turns the frugal environmentalist aesthetic on its head. Sure, it doesn't burn petroleum, and if plugged into a wind turbine or a nuclear plant, it would be a very low-carbon machine. But anyone who buys one will get the most satisfaction from smoking someone's doors off. The Tesla's message is that "green" technology can appeal to the id, not just the superego."
In December 2009, MotorTrend was the first to independently confirm the Roadster Sport's reported 0 to 60 mph time of 3.7 seconds. (MotorTrend recorded 0 to 60 mph of 3.70 seconds; it recorded a quarter-mile test at 12.6 sec @ 102.6 mph.) Engineering Editor Kim Reynolds called the acceleration "breathtaking" and said the car confirms "Tesla as an actual car company. ...Tesla is the first maker to crack the EV legitimacy barrier in a century." 
In November 2009, Automobile Magazine West Coast editor Jason Cammisa spent a week driving a production Tesla Roadster. Cammisa was immediately impressed with the acceleration, saying the car "explodes off the line, pulling like a small jet plane. ... It's like driving a Lamborghini with a big V-12 revved over 6000 rpm at all times, waiting to pounce—without the noise, vibration, or misdemeanor arrest for disturbing the peace." He also took the car to Infineon Raceway in Sonoma, California, and praised the car for its robustness, saying the Roadster,
"wins the Coolest Car I've Ever Driven award. Why? Despite the flat-out sprints, the drag racing, the donuts, the top-speed runs, and dicing through traffic like there's a jet pack strapped to the trunk, Pacific Gas and Electric—which generated power for the Tesla—released into the atmosphere the same amount of carbon dioxide as would a gasoline-powered car getting 99 mpg. And the Roadster didn't break. It didn't smoke, lock up, freeze, or experience flux-capacitor failure. Over the past ten decades, no company has been able to reinvent the car—not General Motors with the EV1, not Toyota with the Prius. And now, a bunch of dudes from Silicon Valley have created an electric car that really works—as both an environmental fix and a speed fix."
In May 2009, Car and Driver technical editor Aaron Robinson wrote a review based on the first extended test-drive of a production Tesla Roadster. Robinson had the car for nearly a week at his home. He complained of "design anomalies, daily annoyances, absurd ergonomics,and ridiculous economics " and stated he never got to see if the car could go 240 miles on a single charge because of the torturous seating forced him to stop driving the car. He also complained of Tesla increasing the car prices on those who had already made deposits and charging extra for previously free necessary components.
In February 2009, automotive critic Dan Neil of the Los Angeles Times called the production Tesla Roadster "a superb piece of machinery: stiff, well sorted, highly focused, dead-sexy and eerily quick." Neil said he had the car for 24 hours but "caned it like the Taliban caned Gillette salesmen and it never even blinked."
In February 2009, Road and Track tested another production vehicle and conducted the first independently verified metered testing of the Roadster. Engineering editor Dennis Simanitis said the testing confirmed what he called "extravagant claims", that the Roadster had a 4.0 s 0 to 60 mph acceleration and a 200-mile (320 km) range. They said the Roadster felt like "an over-ballasted Lotus Elise", but 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. Testing a pre-production car in early 2008, 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".
In January 2009, automotive critic Warren Brown of the Washington Post called the production Roadster "a head-turner, jaw-dropper. It is sexy as all get-out." He described the feeling behind the wheel as, "Wheeeeeee! Drive a Tesla, even if you have to fly to Tesla's Menlo Park, Calif., headquarters, to get your hands on one for a day. ... If this is the future of the automobile, I want it."
In the autumn of 2008, Top Gear's Jeremy Clarkson reviewed two production Roadsters 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. Clarkson also noted, however, that the handling of the car was not as sharp as that of the Lotus Elise: "through the corners things are less rosy." The Stig recorded a time of 1:27.2 on a moist track, faster than a Nissan 370Z on a dry track but slower than a Porsche 911 C2S also on a damp track, and also slower than the Lotus Exige, Exige S and Evora. The segment also showed the car's batteries running flat after 55 miles (89 km), saying that the recharge would take 16 hours and also that the car then broke down. Tesla Motors' spokesperson responded with statements in blogs and to mainstream news organizations that the cars provided to Top Gear never had less than 20% charge and never experienced brake failure.In addition, neither car provided to Top Gear needed to be pushed off the track at any point. Finally, although Clarkson showed a limp windmill and complained that it would take countless hours to refuel the car using such a source of electricity, the car can be charged from a 240V outlet in as little as 3.5 hours. After numerous blogs and several large news organizations began following the controversy, the BBC issued a statement saying "the tested Tesla was filmed being pushed into the shed in order to show what would happen if the Roadster had run out of charge. Top Gear stands by the findings in this film and is content that it offers a fair representation of the Tesla's performance on the day it was tested," without addressing the other misrepresentations that Tesla highlighted to the media. After several weeks of increasing pressure and inquiries from the BBC, Clarkson wrote a blog for The Times of London, acknowledging that "that the film we had shot was a bit of a mess." In the months that followed Clarkson's acknowledgment, the original episode—including the misstatements—reran on BBC America and elsewhere without any editing, though the BBC is still looking into Top Gear's journalism standards, according to British media reports.
In a review of a Roadster prototype before the cars were in serial production, Motor Trend gave a generally favorable review in March 2008, 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 drive-train buck" during the test drive of an early Roadster with the older, two-speed transmission.
In a July 8, 2007, review of a prototype 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." 
In a November 27, 2006, review of a prototype 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." [


INDEX: Award 2007
BusinessWeek: Best Product Design of 2007, Ecodesign
Forbes: Best Cars 2006: New car that best lived up to the Hype
Time: Best Inventions 2008—Transportation Invention
Time: Best Inventions 2006—Transportation Invention
Popular Mechanics: Breakthrough Awards 2006
Global Green USA: Product/Industrial Design
CarDomain: People's Choice: Most Exciting 2007 Car Launch 
2009 Best Green Exotic, duPont REGISTRY



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