Converting a conventional gasoline vehicle to electric power requires the removal of the car's combustion engine and fuel system and installation of batteries and an electric motor. Vehicles with manual transmissions are most suitable for conversion due to the ease of mating the electric motor with the existing transmission.
Converting an existing gasoline or diesel vehicle to electric power first requires that the mechanic remove the engine, exhaust and fuel system to provide room for the electric components. Removing these items also helps reduce the weight of the car and improves its range. The mechanic also must install mounting brackets for the new batteries and the electric motor, and mate the electric motor to a reduction gear to efficiently power the wheels. In most conversions, the way to do this is to lock the vehicle's manual transmission into first or second gear, largely due to the expense of creating a custom reduction gear. The mechanic must also install a relay to direct power to the motor and electrical accessories and to enable the driver to turn the car off and back on.
The complexity of a conversion varies considerably from vehicle to vehicle, as does its cost. Many conversions use lead-acid batteries due to their wide availability and low price, but lithium-ion batteries provide higher power density and more range. Many of those who perform conversions have reported that older rear-engine vehicles from Volkswagen and Porsche provide the easiest conversion experience due to the ease of access to the engine and transmission.