The world is transitioning towards electric vehicles, ditching gas-guzzling internal combustion engine powered vehicles. There are many advantages of EVs over ICE vehicles, such as more efficiency, high instant torque delivery, very low operating costs. Although it costs more to initially own an EV than an ICE vehicle, you will recover the amount while driving your vehicle. Electric Vehicles are a step towards a clean environment because of its nearly zero emissions.
Let’s talk about the most important factor of a car i.e its range. All the EVs present in the market provide a decent range and comes with both ac and dc fast charging modes. The range depends on many factors and how you drive. Some of these factors are temperature, speed, load.
We are going to understand how load affects the range of an electric vehicle.
Electric Vehicles run on electric motors and are powered by the lithium-ion battery packs. Most of the EVs use Brushless DC Motor or a 3 Phase induction motor. They both convert electrical energy into kinetic energy.
The construction of both is different but works on the same principle that is Lorentz force law which states that whenever a current carrying conductor is placed in a magnetic field it experiences a force.
To understand how load affects the range, we have to understand how motors work.
An induction motor is also called a rotating transformer. The transformer and induction motor also work on the same principle. Here the primary winding is stator winding of the motor while the secondary winding is the rotor.
When three-phase supply is applied to the stator rotating magnetic fields are produced with rotating polarities. This speed is called synchronous speed denoted by Ns. When the rotor cuts the rotating magnetic field an emf is induced in the rotor which in turn induces a current in the rotor. Flux is generated on both stator and rotor windings and the interaction between them causes the rotor to rotate.
The rotor chases to achieve the synchronous speed of the stator but it lags. This lag or relative speed is called slip and slip is important to keep the rotor moving. This is basically how a motor works.
What happens when the extra load is applied on the Electric Vehicle?
In an electric car, the motor is always in loaded condition unless it is uncoupled from the shaft. As soon as we step on pedal the motor takes inrush current and delivers instantaneous torque.
Torque is the product of current and flux. When the car is loaded the motor has to apply more torque to keep wheels moving. To accompany this extra torque the motor takes in more current from the battery pack.
The other changes that occur when loading is done are RPM gets reduced and the power factor increases.
What an EV owner has to do with this?
If you understood what happens when an electric car is loaded you may ask, What I have to do with this as an EV owner?
In daily life, you won’t notice much difference but if you have a big family or planning to go on a trip with your belongings you must expect reduced ranges from your EV. Also if you are going to tow another vehicle or cargo, the extra load will also kill the range of your electric car.
So before leaving for a trip keep a check on how much battery require before next recharge or make a plan where you will get your electric vehicle juiced up back.