Why Can’T Electric Cars Charge Themselves With An Alternator?


As electric vehicles (EVs) continue to gain popularity and market share, many people are starting to ask interesting questions about their technological capabilities. One common question is, “Why can’t electric cars charge themselves with an alternator?” To answer this question, we need to examine the basic principles of energy conservation and the workings of an alternator. In this blog post, we will delve into these topics and explain why generating power through an alternator is not a feasible solution for electric vehicles.

Understanding the Alternator

An alternator is a device used in internal combustion vehicles to convert mechanical energy into electrical energy, which is then used to charge the vehicle’s battery and power its electrical systems. The alternator is driven by the engine, usually through a belt, and generates alternating current (AC) electricity as the engine runs.

At first glance, it might seem like a good idea to use an alternator to recharge the batteries of an electric vehicle. After all, the device is already widely used in conventional vehicles for charging their batteries. However, there are several reasons why this is not feasible or efficient.

Energy Conservation

The first reason why an alternator cannot be used to charge an electric vehicle’s battery while it’s driving lies in the principle of energy conservation. This principle states that energy cannot be created or destroyed, only converted from one form to another. In the context of an electric vehicle, the energy stored in the battery is used to power the electric motor, which in turn provides the mechanical energy necessary to move the vehicle.

If we were to use an alternator to charge the battery while the vehicle is in motion, we would essentially be using the energy generated by the electric motor (mechanical energy) to create electrical energy through the alternator. This would result in a net loss of energy due to the inefficiencies of the conversion process and the additional load placed on the electric motor. In short, the energy gained from the alternator would not be enough to offset the energy used by the electric motor, leading to a decrease in overall efficiency.

Regenerative Braking

Electric vehicles already have a more efficient method of recovering energy while in motion: regenerative braking. Regenerative braking refers to the process of capturing the kinetic energy that would otherwise be lost during braking and converting it back into electrical energy to recharge the battery. This process is much more efficient than using an alternator, as it doesn’t require any additional load on the electric motor and takes advantage of energy that would otherwise be wasted.

Weight and Space Constraints

Another reason why using an alternator in an electric vehicle is not feasible is the weight and space constraints associated with the device. Electric vehicles are designed to be as lightweight and efficient as possible, with every component carefully optimized to minimize energy loss. Adding an alternator to the vehicle would not only increase its weight, but also require additional space for installation and cooling.


In conclusion, using an alternator to recharge an electric vehicle’s battery while it’s driving is not a feasible or efficient solution. The principle of energy conservation dictates that the energy gained from the alternator would not be enough to offset the energy used by the electric motor, resulting in a net loss of energy. Additionally, electric vehicles already employ regenerative braking, a more efficient method of recovering energy while in motion. Finally, weight and space constraints make the addition of an alternator to an electric vehicle impractical. Instead, the focus should be on improving the efficiency of electric vehicle components and developing more advanced charging infrastructure to support the growing demand for electric vehicles.