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For all the energy required to propel a vehicle, not all of it makes it to the wheels. Some of it is lost to friction and heat. Vehicle inefficiency can be classified into two categories of losses:road-load and energy conversion. At Tesla, careful attention is given to both to achieve the maximum range. The Tesla Roadster leverages both an incredible electric powertrain and an engineer’sobsession with efficiency to be the most efficient production sports car on the market today.

ROAD-LOAD
ROAD-LOAD
All vehicle types, regardless of what powertrain they use, need to overcome road-load.It includes wind resistance, mechanical friction (bearings, hubs, driveshaft, etc.), and tire rolling resistance. Road-load affects all vehicles. As a car speeds up, wind resistance increases; thereis more air for the car to “push” out of the way. Therefore, road-load is greater at higher speeds and is dependent on the aerodynamics of the vehicle. Tesla engineers are focused on decreasingaerodynamic losses while achieving beautiful styling. Road-load can be minimized by designing brakes, bearings and other rotating components with less friction. It is also important to use tires that havelow rolling resistance and make the vehicle as light as possible. Energy saved by decreasing road-load can have a significantly positive impact on range. The Model S will be one of the most aerodynamicsedans ever built with all components tuned to minimize friction and achieve the highest possible range.

ENERGY CONVERSION LOSSES
Two theoretical cars with identical road-load could have verydifferent overall efficiency based on how effectively they convert energy before it turns to the wheels. Electric vehicles have the lowest overall energy conversion losses.
ELECTRIC VEHICLE EFFICIENCYIn an electric vehicle, chemical energy is stored in a battery. Lithium-ion batteries are used in Tesla vehicles because of high energy density. Converting the chemical energy to free electrons...