An electric vehicle uses a very simple power train. The best example is an electric golf cart on the green. It is clean, quiet and has zero emission. The process of converting a car to electric is to replace the internal combustion engine with an electric motor. The motor will generate the torque need to move the car forward. A series of lead flooded acid batteries will be used to supply the power to the motor. To control the speed of the car, a current resistance regulator is connected between the batteries and the motor. The regulator acts as the accelerator paddle of the car. Finally, the whole system is linked to a central circuit board that monitors the condition of the motor and status of the batteries.
All these information may sound like Greek if you are not familiar with the internal workings of a car. In this case, you can outsource the conversion project to a mechanic. To be prudent, you should at least have some basic understanding of the whole modification process. This is to ensure you are not paying for unnecessary parts retrofitted into your car. There any many good quality electric car conversion guides that you can purchase from the web.