Why Can’t an Alternator Charge an Electric Car?

Regular vehicles have alternators that charge their battery while in motion. Similarly, “why can’t we have electric cars that charge themselves?” This is a common question from curious electric car owners and EV enthusiasts. The idea is to have a regenerative power system that charges an EV as it runs.

alternators on electric cars

To resolve this contemplation, we need to know precisely how an alternator works. We also need to understand where its energy emanates from. The big question remains, “Why can’t an alternator charge an electric car?”

An alternator can’t charge an electric car because it would consume more power than the EV battery can produce. The mechanical energy that an alternator uses in a gasoline-powered vehicle is supplied by the engine. Unfortunately, EVs don’t use internal combustion engines.

How Does Alternator Work?

A vehicle alternator turns mechanical energy into electrical power. It does this through a process known as electromagnetic induction. When you turn on your car, the engine drives the drive belt. This belt is connected to the alternator pulley.

The pulley turns the rotor shaft of the alternator. This in turn spins a particular set of magnets around a coil. These rotating magnets produce alternating current around the coil to the rectifier.

Furthermore, the alternator’s rectifier transforms the alternating current into DC power. It helps to power your car’s electrical systems.

The alternator consists of three major components. These are; a rotor (or armature), a stator, and a rectifier. The rotor is connected to the crankshaft. It rotates around a set of stationary coil windings, which are part of the stator.

A magnetic field is created as the rotor spins, which induces an AC current in the windings. Then, the rectifier converts this alternating current (AC) into a direct current (DC). The car battery and other electrical components use the DC current.

The alternator also contains other components. Examples of such components are the alternator fuse, the voltage regulator and the diode bridge. The voltage regulator controls the amount of voltage that the alternator produces. The diode bridge prevents the current from flowing in the wrong direction. Finally, an alternator fuse protects the electrical system from excessive current and prevents damage to the alternator and other components.

Alternators are designed to last long. Unfortunately, that’s not always the case. Wear and tear, heat damage or frayed wires can affect the alternator’s service life.

Why can’t an Alternator Charge an Electric Car?

An alternator can’t charge an electric car because of the energy it consumes, which is more than the EV battery can supply. Conventional vehicles generate mechanical energy for the alternator through their combustion engines. Meanwhile, these engines are powered by fossil fuels. Conversely, an EV uses an electric motor and a rechargeable battery.

Also, an alternator lacks the characteristics required for charging electric vehicles. Hence, their incompatibility. EV manufacturers may have considered the thought at one point or the other. But no way!
An alternator can’t function like an EV charger. For example, an EV home charger uses around 11.81 kWh/day to charge the EV to replenish the driven range. This accumulates to around 353.3 kWh/month and 4,310.65 kWh/year.

The electric motor and battery used in an electric car are perfect for its operation. Knowing the kind of car you’re buying is important to align with the vehicle’s requirements. It’s worth noting that most of them are not manufacturing mistakes.

Can an Electric Car Charge Itself?

Electric cars cannot charge themselves. They lack the technology required to regenerative charge their battery faster. Their batteries can’t be charged faster than the amount of energy they spend. The EV battery is designed to be recharged by a unique charging system.

Some electric vehicles use a regenerative braking system to recharge their batteries partially. However, the battery cannot be adequately recharged while the car is in motion. This is because very little amount of energy is produced.

A regenerative braking system alone is not sufficient. This is because the power required to move the EV at highway speeds is much higher than what it can provide. The idea of charging electric cars while driving is still a mirage.

Another reason is due to the limitation of lack of high-powered charging equipment. Therefore, the notion of having alternators on electric cars is still improbable. This is a reality even though EVs continue to advance and become more efficient.

Does Tesla Cars have Alternators?

Charging Tesla

Tesla electric cars do not use an alternator like fossil fuel-powered vehicles. But they have an energy conversion system. It is designed to convert battery power to usable energy and back directly. This is known as a DC-to-DC converter.

If you were asking, “Do electric cars have alternators?” The answer is No! EVs do not have an alternator due to the absence of an internal combustion engine. Remember, an alternator goes hand in glove with a diesel/gasoline-powered combustion engine.

None of the above are present in a Tesla EV. Rather, they are powered by a rechargeable battery and an electric motor. These components make it possible for Tesla cars to circumvent exhaust emissions.

They also omit conventional fossil fuel system components. Such components include fuel pumps, fuel lines, and fuel tanks. Having an electric car with an alternator means these components must be present.


Automobiles are manufactured with technologies that suit their operations. However, there are room for technological advancement. Internal combustion engine vehicles are designed with a different technology from electric cars.

So, if you were asking, “Why can’t an alternator charge an electric car?” The simple reason is that electric cars don’t use internal combustion engines. Hence, they can’t generate the mechanical energy required to power the alternator.


Mr. Shafiqule Islam is a graduated Mechanical Engineer and has more than 15 years experience of repairing and maintenance of different brand vehicles like Toyota, Mitsubishi, Ford, Mercedes, BMW etc. He is also giving training to Mechanics. He has started writing to share his practical knowledge to Vehicle Owners, Drivers and Mechanics to keep their cars at best fit.

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