The question some people have in their minds is if electric cars have alternators. If not, why they are not?
If you check out most EV manufacturers (if not all of them) like Tesla, Nissan, Rivian, BMW, Zoox, or someone else, you will find out that they are not installing alternators into their EVs (Electric Vehicles). Most of them prefer to install high voltage, high-capacity batteries and DC-to-DC converters.
Thus, millions of electric vehicles operating in this world don’t have installed alternators.
But why is that? To figure it out, we first need to know what is an alternator and how it works.
What is an alternator?
An onboard generator, or an alternator, in a car, is one of the key components of a gasoline car’s engine for converting energy. It is typically mounted toward the front of the engine. While the main battery is needed to start your car when it’s off, the alternator keeps your car running when the engine is running.
The alternator is used to power up the electrical systems in your car, which are, headlights, dashboard, electric steering, radio, navigation systems, power windows, wipers, sensors, parking sensors, board computer if you have one, and other accessories, all of them are powered up by an alternator.
How does it work?
Well, when you start your internal combustion engine (ICE, or a fossil fuel engine), a rotary element is started, connecting the motor of the engine and the alternator with a belt. The motor rotates forward, thus creating mechanical energy.
The mechanical energy created (or rotational energy) by the engine is used to move a vehicle, and the rest of the mechanical energy, which is called waste rotational energy, powers an alternator. The alternator is converting waste rotational energy into electrical energy to power up the car’s electrical system.
The claw rod design creates an AC waveform that rectifies more efficiently than a sine wave. In an “alternator”, alternating current is generated in a stationary stator and then converted to direct current using rectifiers (diodes).
Typical car and light truck generators use the Lundahl or “claw” field design. It uses a shaped iron core on the rotor to create a multipole field from a single coil winding. The poles of the rotor look like the fingers of two hands interlocked with each other.
The coil is mounted axially inside it, and the excitation current is supplied by slip rings and carbon brushes. In these alternators, the field and stator windings are cooled by axial airflow generated by an external fan attached to the drive belt pulley.
The mechanical energy produced by the engine, in turn, is powered by fuel consumption, i.e., gasoline or diesel, depending on what type of engine is installed in your car. It is also called chemical energy.
The combustion of fuel in an internal combustion engine is a set of chemical reactions, which are the element for powering the engine, and which are called chemical energy.
This is a very useful thing that, when used correctly, can help you make better use of the potential of your ICE.
But do electric cars have alternators?
In the end, the alternator is a useful, economical thing and allows you to charge a car battery while driving. But as it was mentioned at the very beginning, most electric vehicle manufacturers do not install an alternator in electric cars.
But why don’t electric cars have these? Is the electric car battery enough for all the vehicle’s needs?
There are a lot of reasons for that, but let’s take a look at several of them.
Reason number 1: Electric cars have no engine
As you all know very well, most electric cars are equipped with electric motors, not internal combustion engines. An electric motor is a much more highly specialized thing than an internal combustion engine.
If the ICE consumes the chemical energy of the fuel, converting it into mechanical energy of rotation, and does not require electrical energy to operate, electrical energy is needed to operate the electric motor. Well, that is, you guessed what the catch is. At least two elements that are necessary for the operation of the alternator are missing inside the electric car.
However, the electric motor itself has the ability to transform electrical energy into mechanical energy, or rotational energy. After all, an electric motor is necessary to set the electric car in motion, and not otherwise, but the difference is obvious.
But the original source of mechanical energy in an electric motor is not chemical energy, but electrical energy fed by a high-voltage battery. The same electricity is used to power all the electrical devices and electrical accessories in an electric car, which are often the same as in conventional gasoline cars or diesel cars.
That, and the electric motor produces only rotational energy and does not consume chemical energy.
Electric cars cannot waste rotational energy, which is more than enough in ICE cars. In this case, if you try to install an alternator in an electric car, your high-voltage battery will quickly drain due to uneven use of electricity.
And this takes us to reason number two.
Reason number two is electric cars have no extra energy to waste
Installing the alternator into electric vehicles is a very inefficient way of converting electrical energy into rotation energy to… convert it into electrical energy again.
Without going into details, physics says that it is impossible to create something out of thin air. And in the same way, the electricity in your electric vehicles, or in your gasoline cars, does not come from clean air because everything needs a power source that sets the gas car in motion.
An alternator does not create energy. It converts one form of power into another form.
In an ICE car, it’s a fossil fuel stored in a gas tank, while in an Electric Car, it’s the electricity stored in an electric car battery. Electricity, which is originally a fuel for an electric vehicle, cannot be used to create rotational energy for an alternator. This is the consumption of electrical energy for the production of electrical energy.
If it were possible, then electric cars would become real Perpetual motion machines. And perpetual motion machines, according to the first and second laws of thermodynamics, are impossible.
The alternator requires a lot of rotation to generate electricity. Electric vehicles don’t have as much mechanical energy as an internal combustion engine, that is, they don’t have the same rotational waste energy that an alternator needs.
Theoretically, you could try installing an alternator in your electric car, but when you look at the percentage of charge in your battery, you will be very surprised that more energy is spent on the alternator’s rotation than it is returned to charge the same battery pack.
The battery of an electric car cannot be used to produce electricity since it itself requires electricity from charging stations, and the alternator wastes more rotation than it produces electricity.
And so, to sum it up in a nutshell, we found out that alternators require an engine and the combustion of fuel to generate electrical power. And also that an alternator installed on an electric car will use more battery electricity than it produces. Simply and easily.
And finally, the third reason why electric cars do not have alternators…
Reason number three is electric vehicles don’t need alternators
The lack of a power source, which is necessary for the operation of the alternator, makes the installation of such devices in electric cars meaningless. Rotation requires a lot of energy, which an electric car cannot afford.
You see, the efficiency of an electric car is much higher than that of an internal combustion engine. ICE generates a lot of rotational energy, which is required to operate the alternator.
ICE efficiency is 30 percent maximum, and it’s not used to produce electricity. The engine cannot power up the electrical appliances and the battery, so, therefore, the alternator on the ICE is vital, unless, of course, you can do without the electrical appliances installed in the car.
In an Electric Car, on the other hand, high-voltage battery power the vehicle’s electric motors and electrical appliances, as well as other electrical accessories, like… phone chargers and air conditioners for example.
The efficiency of the electric motor is much higher, from 70 to 85 percent; therefore, the battery does not have extra electrical energy to convert it into rotational energy.
So, what’s the point? Well, actually there is a better device than the alternator, and this device is used in electric cars.
A device called a DC-to-DC converter
What is this?
If we only want to convert direct current from one voltage to another, there is a much easier and more efficient way to do it. This is through a device called a DC-to-DC converter.
It is an electronic device that takes a direct current of voltage and converts it to another voltage. It’s not “free energy” though.
Converting to a higher voltage also means getting a lower current. Getting a higher current also means getting a lower voltage. In any case, it is still the same amount of energy minus the losses that appear as heat. Basic DC/DC converters dissipate heat through the metal case. Higher power converters have heatsinks, fans, or even active liquid cooling.
DC/DC Converters have several advantages over alternators. They are compact. They save weight. They are more efficient. There are no moving parts – no belts to replace, no pulleys, and no bearings. That also means they are maintenance-free.
How does it work?
DC-to-DC converters in high-frequency DC circuits that use high-frequency switches and inductors, transformers, and capacitors to melt switching noise into regulated DC voltages. Closed loops detect a constant output voltage connection, even when using input voltage and output current. At 90% efficiency, they tend to be much more efficient and smaller than linear regulators.
Their return is noisy and cyclical. DC/DC converters are non-isolated and isolated. Isolation decides whether to connect the input ground to the output ground.
Converters of this type allow you to better distribute voltage to all electronic devices in your electric car and also allow you to better save energy in a high-voltage battery.
But this does not deprive us of one problem. After all, an electric car needs an electric charge, and therefore charging stations are needed.
Regenerative braking system
Braking is a very common operation that millions of drivers do every day. However, what not everyone knows is that during braking, a large amount of kinetic energy is generated. This energy is the energy an object has because of its motion.
Regenerative braking is a way of using the energy wasted in the process of decelerating a car to recharge car batteries. In a conventional car, braking simply wastes energy, but with regenerative braking, some of the energy can be reused.
Regenerative braking systems are common in many modern vehicles. On petrol and diesel models, it is used to charge the battery that controls the vehicle’s various auxiliary systems, which means less engine work and less fuel burn.
In these vehicles, the system is almost invisible to the driver, but in hybrid and pure electric vehicles, regenerative braking plays a more active and obvious role. In these models, regeneration of the brakes can help charge the larger batteries directly driving the vehicle.
How does regenerative braking work?
The electric motor in your electric car works in two directions – one to drive the wheels and move the car, and the other to recharge the battery. When you lift your foot off the accelerator pedal and apply the brake, the engine changes direction and starts returning energy to the battery.
As this process begins, you may feel the car begin to slow down. Each car with this feature has a different feel because manufacturers can program the amount of regenerative braking when you release the pedal. All cars still have normal brakes, so if you press the pedal hard enough, the hydraulic system will kick in to stop you quickly (depending on your speed).
Regenerative braking varies by EV model and braking conditions. The greatest amount of kinetic energy is generated on steep and long descents. As they say, it is better to live at the foot of a mountain than at its very top.
Conclusion
And just as we have already found out, electric vehicles do not have alternators.
Why don’t they have them? Because they are useless inside an electric car, which has better and more adapted devices than an alternator.
In theory, this question was useful for those who are looking for a way to recharge the battery of an electric car, believing that since the alternator allows you to charge the battery of a conventional car, then it will be able to charge the battery of a car battery in an electric car.
But, as we found out from the article, this is meaningless, since the alternator loses its power source, that is, the ICE and the high-voltage battery cannot replace the “ICE” for the alternator, since it cannot afford to waste energy. That, and unlike the ICE, the electric car’s battery powers up all the electrical components in the vehicle.
An electric car cannot charge itself with an alternator because the alternator uses more electricity than it produces.
Also, EVs have a better device to evenly distribute battery voltage and convert battery current to DC perfectly to save more electric vehicle battery power.
So for the reasons, I have mentioned, and some other reasons not mentioned in this article, electric cars have no alternators.
Small FAQ
Is there an electric car that charges itself while driving? No. There is a way to put some of the energy back into the electric car battery with the help of regenerative braking, but there is no way to self-charge the battery.
Can an electric car charge itself with an alternator? As we figured out, an alternator needs an engine to convert one form of energy into another, and therefore it will consume more energy than it creates.
Do Teslas have alternators? No. Tesla cars are not supplied with alternators as standard. Read about Best Tesla apps for Tesla car owners in the article