Electric vehicles (EV) are easier to live with and are cheaper to run than conventional vehicles. EVs are less likely to require repairs, and owners save thousands of euros in fuel and garage services due to the high-efficiency electric power train, energy recovery through the regenerative braking and low maintenance required.
The battery is the heart of the EV and is the vehicle’s residual value. The battery is very pricey to replace, and the range of the EV depends on its capacity and health level. Batteries lose their initial capacitive range every year, and the rate at which this loss occurs depends mainly on the storage conditions, driving style and charging schemes applied to the battery.
The liveability of the battery can suffer damage when unused for too long especially if left discharged sitting in a garage or, worst, under the scorching sun or in sub-temperature on the street. Charging up the battery to full-cycle every time and frequent recharging of the battery will degrade it more quickly. When practically possible, consider a charging scheme ranging from 20 up to 80 per cent. However, the optimal way for long trips is to charge the battery to 100 per cent and drive until it just about runs out.
Before purchasing an EV, analyse your driving range and choose the battery capacity accordingly. The good news is that EV batteries generally last more than 10 years under normal driving conditions, and in most cases, one will still be able to drive the car as usual but with only a bit less range. Most electric vehicles use ventilators, coolants and refrigerants to prevent the batteries from overheating. On average, coolant servicing is applied every 80,000km or every five years. However, it is best to refer to the EV owner’s manual to check the frequency of flushing or replenishing of any coolant in the EV system.
Typically an EV uses a combination of a regenerative and conventional friction braking system. Regenerative braking allows the EV to operate on what is called one-pedal driving. By pressing the accelerator pedal sets the EV to accelerate, while when releasing the pedal, the vehicle will decelerate due to a braking torque similar to the engine brake in a vehicle equipped with a conventional combustion engine. When the EV brakes, the motor switches to generator mode and the vehicle’s kinetic energy is converted back into electrical energy, thereby recharging the battery pack. The hydraulic section of the braking system is not used as frequently as in a gasoline-powered vehicle, but one must still look after the brake pads, and even though pads and discs tend to last much longer, the brake fluid needs to be replaced from time to time. The hydraulic fluid is hygroscopic, which absorbs water moisture from the air.
The battery is the heart of the EV
The amount of energy recovery depends on the different driving styles, and together with the regenerative braking settings, it is difficult to give an exact number when the brake pads are to be replaced. Therefore when driving an EV, the number one game is to make the brake pads last long enough and never need to replace them again. On average, the Brake Fluid is to be flushed every 50,000km or five years, whichever comes first.
Same as in other vehicles, the EV uses the same form of wheels. Regular tyre air pressure checks and wheel balancing and alignment is requisite. The significant weight of the EV combined with the added acceleration due to the instant power and torque delivered by the electrical motor will lead to the tyres needing replacement more often than with a conventional vehicle. Also, tyre rotation is recommended every 10,000KM. A safe way is to purchase replacement tyres specifically designed for EV, which generally contribute less rolling friction, are quieter and are more durable than traditional ones, but still, regular tyre maintenance will remain an essential service to the EV.
Different EV use different types of electric motors, but the most common is the AC induction motor. Usually, the electric motor’s performance is very efficient, and its life expectancy is anywhere from 15 to over 20 years. However, various factors, including unexpected load changes fluctuations, input power supply, and different environmental factors like humidity and temperature, may influence an electric motor’s performance. A reduced voltage supplied from the battery may lead to overcurrent to maintain torque, damaging the electric motor and/or its speed drive. EV motors will break down quicker than intended if contamination from chemicals or foreign particles like dirt and dust debris are trapped inside it, damaging the ball bearings in ways that lead to high levels of wear and vibration. The cooling system and heat sink of the electric motor and speed-drive shall be serviced on time, since it may be limiting the motor’s ability to regulate the temperature, rendering the motor to be less efficient, which results in overheating and may cause a shortage of the windings due to insulation failure.
The conventional internal combustion engine can have as many as 2,000 moving parts, while the power drivetrain in an EV can function using only 20 parts. The continuous torque generated by the electric motor contributes to many EVs having only a single set of gears to power the wheels.
Fewer moving parts mean less likelihood of mechanical problems. On the other hand, EVs contain a costly battery, electric motor, and speed drive with complex electrical and electronic components.
One might be glad to learn that EVs need no oil changes and do not worry about spark plugs or timing belt changes. It is a considerable upside that the friction parts of the EV are much more lived than on vehicles with a combustion engine because most of the braking is done by the drag generated by the energy recovery marking the electric vehicle as very efficient and convenient.
Andy Bugeja is Senior Lecturer, Institute of Engineering and Transport, MCAST