An electric car is a type of alternative fuel car that utilizes and motor controllers instead of an internal combustion engine (ICE). The electric power is usually derived from battery packs in the vehicle.

In general terms an electric car is a rechargeable battery electric vehicle. Other examples of rechargeable electric vehicles are ones that store electricity in ultracapacitors, or in a flywheel.

Vehicles using both electric motors and other types of engine are known as hybrid electric vehicles and are not considered pure electric vehicles (EVs) because they operate in a charge-sustaining mode. Hybrid vehicles with batteries that can be charged externally to displace are called plug-in hybrid electric vehicles (PHEV), and are pure battery electric vehicles (BEVs) during their charge-depleting mode. Electric vehicles include automobiles, light trucks, and neighbourhood electric vehicles.

Below are some examples of electric cars currently available for sale.

Low speed

Cars not capable of reaching 60 km/h, required by the Autobahn

City speed

Cars capable of at least 60 km/h, but not 80 km/h

Interstate capable

Cars capable of at least 80 km/h

Relation with hybrid vehicles

Vehicles using both electric motors and Internal Combustion Engines are examples of hybrid vehicles, and are not considered pure electric vehicles (also called all-electric vehicles) because they operate in a charge-sustaining mode. Hybrid vehicles with batteries that can be charged externally to displace some or all of their ICE power and gasoline fuel are called plug-in hybrid electric vehicles (PHEV), and are pure EVs during their charge-depleting mode. The coming Chevrolet Volt is of this type. If batteries cannot be charged externally, the vehicles are called regular hybrids.

Comparison with internal combustion vehicles

Purchase cost

Batteries are usually the most expensive component of electric cars, though the price per kilowatt-hour of energy capacity has fallen in recent years for the more recently introduced technologies such as lithium-ion and lithium-polymer, as would be expected for any new technology. Older technologies such as lead-acid have become more expensive due to increase in materials cost, particularly lead, driven by demand for use in powered bicycles (particularly in China and India) and in uninterruptible power supplies to support small computer systems. Since the late 1990s, advances in battery technologies have been driven by skyrocketing demand for laptop computers and mobile phones, with consumer demand for more features, larger, brighter displays, and longer battery time driving research and development in the field. The electric vehicle marketplace has reaped the benefits of these advances, but the cost per unit of energy capacity still favours older, heavier, less efficient technologies.

Some batteries can be leased or rented instead of bought (see Think Nordic). In 1947, in Nissan's first electric car, the batteries were removable so that they could be replaced at filling stations with fully charged ones.

Running costs

Electric car operating costs can be directly compared to the equivalent operating costs of a gasoline-powered vehicle. A litre of gasoline contains about 8.9 kW·h of energy. To calculate the cost of the electrical equivalent of a litre of gasoline, multiply the utility cost per kW·h by 8.9. Because automotive internal combustion engines are only about 20% efficient, then at most 20% of the total energy in that litre of gasoline is ever put to use.

A car powered by an internal combustion engine at 20% efficiency, getting 8 L/100 km (30 mpg), will require (8.9*8)*0.20 = 14.2 kW·h/100 km. At a cost of $1/L, 8 L/100 km is $8 per 100 km. A battery electric version of that same car with a charge/discharge efficiency of 81%, and charged at a cost of $0.10 for kW·h would cost (14.2/0.81)*0.10 = $1.75 per 100 km, or would be paying the equivalent of $0.22/L. The Tesla uses about 13 kW·h/100 km, the EV1 used about 11 kW·h/100 km.

Servicing costs should be lower for an electric car. The movie Who Killed the Electric Car shows a comparison between the parts that require replacement in a gasoline powered car and the EV1 (none), stating that they bring the cars in every 5,000 miles, rotate the tires, fill the windshield washer fluid and send them back out again. Even brakes require less maintenance because of the regenerative braking, the same as with a hybrid.

Electric cars using lead-acid batteries require replacement of the battery pack on a regular basis, while internal combustion engines can last the life of the vehicle, with routine repairs. Lithium-ion and NiMH batteries typically last the life of the vehicle. No Toyota Prius has ever needed its NiMH battery replaced from wear and tear.

Energy efficiency

An electric car's efficiency is affected by its charging and discharging efficiencies. A typical charging cycle is about 85% efficient, and the discharge cycle converting electricity into mechanical power is about 95% efficient, resulting in 81% of each kW·h is put to use. The electricity generating system in the USA loses 9.5% of the power transmitted between the power station and the socket, and the power stations are 33% efficient in turning the calorific value of fuel at the powerstation to electrical power. Overall this results in an efficiency of 0.81*0.3=24.2% from fuel in to the power station, to power into the motor of the EV.

Production and conversion electric cars typically use 10 to 23 kW·h/100 km (0.17 to 0.37 kW·h/mi). Approximately 20% of this power consumption is due to inefficiencies in charging the batteries. Tesla Motors indicates that the well to wheels energy consumption of their li-ion powered vehicle is 10.9 kW·h/100 km (0.176 kW·h/mi). The US fleet average of 10 L/100 km (23 mpg US) of gasoline is equivalent to 96 kW·h/100 km (1.58 kW·h/mi), assuming 100% efficiency, and the 3.4 L/100 km (70 mpg US) Honda Insight uses 32 kW·h/100 km (0.52 kW·h/mi) (assuming 9.6 kW·h per litre of gasoline and 100% efficiency), so hybrid electric vehicles are relatively energy efficient, and battery electric vehicles are much more energy efficient.

Carbon dioxide emissions

While electric cars are considered zero-emission-at-tailpipe-vehicles, they cause an increase in electrical generation needs. Generating electricity and providing liquid fuels for vehicles are different categories of the energy economy, with different inefficiencies and environmental harms. According to the Electric Vehicle Association of Canada, (who sell electric vehicles)^[40] CO₂ and other greenhouse gas emissions are minimal for electric cars powered from sustainable electricity sources (for example, by solar energy) or for internal combustion engine cars that are run on renewable fuels such as biodiesel.

If the object of the exercise in looking at alternatives to conventional vehicles is to reduce CO₂ emissions, then that has to mean using the most carbon-efficient vehicle you can buy. For the "average" US grid, currently a diesel is better than an EV. Most electricity generation in the United States is from fossil sources, and a lot of that is from coal, according to the U.S. Department of Energy. Coal is more carbon-intensive than oil. Overall average efficiency from US power plants (33% efficient) to point of use (transmission loss 9.5%), (US DOE figures) is 29.87% . Accepting 90% efficiency for the electric vehicle gives us a figure of only 26.88% overall efficiency. That is lower than the efficiency of an internal combustion engine(Petrol/Gasoline 30% efficient, Diesel engines 45% efficient - Volvo figures). The actual result depends on different refining and transportation costs getting fuel to a car versus a power plant. Diesel engines can also easily run on renewable fuels, biodiesel, vegetable oil fuel, with no loss of efficiency. Using fossil based grid electricity entirely negates the in vehicle efficiency advantages of electric cars. The major potential benefit of electric cars is to allow diverse renewable electricity sources to fuel cars.

A modern TDI PD or common rail type diesel engined vehicle, is almost twice efficient when using fossil diesel than an EV running on grid electricity which is mostly from fossil fuel. It can also run on renewable waste vegetable oil fuel, which is viewed as carbon neutral, or low carbon impact if processed into biodiesel, but controversial if new oil is used, because biofuels have been blamed for higher world food prices, (particularly US bio-ethanol) and increased rain forest depletion to grow palm oil. As well as waste oil, new vegetable oil fuels from algae, and forestry waste being piloted in Finland with Nokia venture capital, are new renewable diesel engine fuel sources that are coming on stream.

Electric vehicles did not win the US 'Tour de Sol' competition for greenest car, a VW TDI running on Waste Vegetable Oil did^.

The use of solar, wind, nuclear electric generation along with carbon capture for fossil fuel powered plants means that in the long run, electric vehicles will produce less carbon dioxide over their life time since it is impractical to reduce carbon dioxide at the tailpipe of diesel/bio fuelled cars. Based on GREET simulations, electric cars can achieve up to 100% reductions with renewables electric generation vs 77% will B100 (100% bio-diesel car). Of course at present only 32% reductions of carbon dioxide is available for electric cars with current US Grid due to heavy fossil fuel use and inefficiencies.

Range vs cruising speed

The trade-off for range against cruising speed is well known for IC vehicles, typically a cruising speed of around 50 mph is near-optimal, although for specific cars it could fall as low as 25 mph, or as high as 60 mph.

For electric vehicles the equation is less complex, and maximum range is achieved at comparatively low speeds.

Acceleration performance

Although some electric vehicles have very small motors, 15 kW (20 hp) or less and therefore have modest acceleration, the relatively constant torque of an electric motor even at very low speeds tends to increase the acceleration performance of an electric vehicle for the same rated motor power. Another early solution was American Motors’ experimental Amitron piggyback system of batteries with one type designed for sustained speeds while a different set boosted acceleration when needed.

Electric vehicles can also utilize a direct motor-to-wheel configuration which increases the amount of available power. Having multiple motors connected directly to the wheels allows for each of the wheels to be used for both propulsion and as braking systems, thereby increasing traction. In some cases, the motor can be housed directly in the wheel, such as in the Whispering Wheel design, which lowers the vehicle's centre of gravity and reduces the number of moving parts. When not fitted with an axle, differential, or transmission, electric vehicles have less drivetrain rotational inertia.

A gearless or single gear design in some EVs eliminates the need for gear shifting, giving such vehicles both smoother acceleration and smoother braking. Because the torque of an electric motor is a function of current, not rotational speed, electric vehicles have a high torque over a larger range of speeds during acceleration, as compared to an internal combustion engine. As there is no delay in developing torque in an EV, EV drivers report generally high satisfaction with acceleration.

For example, the Venturi Fetish delivers supercar acceleration despite a relatively modest 220 kilowatts (300 hp), and a top speed of around 160 km/h. Some DC motor-equipped drag racer EVs, have simple two-speed transmissions to improve top speed. The Tesla Roadster prototype can reach 100 km/h (62 mph) in 4 seconds with a motor rated at 185 kW (248 hp).

Travel range before recharging and trailers

The range of an electric car depends on the number and type of batteries used, and the performance demands of the driver. The weight and type of vehicle also have an impact just as they do on the mileage of traditional vehicles. Electric vehicle conversions depends on the battery type:

• Lead-acid batteries are the most available and inexpensive. Such conversions generally have a range of 30 to 80 km (20 to 50 mi). Production EVs with lead-acid batteries are capable of up to 130 km (80 mi) per charge.

• NiMH batteries have higher energy density and may deliver up to 200 km (120 mi) of range.

• New lithium-ion battery-equipped EVs provide 400–500 km (250–300 mi) of range per charge.^[61] Lithium is also less expensive than nickel.

Finding the economic balance of range versus performance, battery capacity versus weight, and battery type versus cost challenges every EV manufacturer.

With an AC system regenerative braking can extend range by up to 50% under extreme traffic conditions without complete stopping. Otherwise, the range is extended by about 10 to 15% in city driving, and only negligibly in highway driving, depending upon terrain.

BEVs (including buses and trucks) can also use genset trailers and pusher trailers in order to extend their range when desired without the additional weight during normal short range use. Discharged battery set trailers can be replaced by recharged ones along a route. If rented then maintenance costs can be deferred to the agency.

Such BEVs can become Hybrid vehicles depending on the trailer and car types of energy and powertrain.