How Does an
Electric Car Work?
A battery powers a motor through an inverter. The motor turns the wheels through a single-speed reduction gear. Regenerative braking recovers energy when slowing down. Here is the plain English UK guide to how an electric car actually moves and stops.
Simply. A lithium-ion battery stores electrical energy. An inverter converts the battery's DC current into AC current that drives an electric motor. The motor produces rotational torque which transfers through a single-speed reduction gear to the drive wheels. When braking, the motor acts as a generator and recovers energy back into the battery. There is no combustion, no fuel, no exhaust and no multi-speed gearbox. The whole drivetrain has around 90 percent fewer moving parts than a petrol car.
Traction Battery Voltage
UK EVs operate at 350V to 800V DC. The newest 800V architectures (Porsche Taycan, Hyundai Ioniq 5) enable faster charging.
Battery to Wheels
Around 85 percent of energy from the wall socket reaches the wheels. Petrol cars typically waste 70 to 80 percent as heat.
EV Drivetrain
An EV drivetrain has roughly 20 moving parts vs 200+ in a petrol drivetrain. Far fewer wear items.
Reduction Gear Ratio
Most UK EVs use a single fixed reduction gear (typically 9:1) connecting motor to wheels. No shifting needed.
What this page covers
How a UK electric car turns electricity into motion
An EV works on a simple principle. Electrical energy stored in a large battery is converted into mechanical motion by an electric motor. The motor turns the wheels through a single-speed reduction gear. Compared to the complexity of a petrol drivetrain (combustion, multi-speed transmission, exhaust system), the EV approach is dramatically simpler.
The battery
The traction battery is the largest and most expensive component. UK EVs typically have battery packs between 40 kWh and 100 kWh stored capacity. The pack consists of thousands of individual lithium-ion cells arranged in modules that connect in series and parallel to produce the right voltage and capacity. Most modern UK EVs operate at 350V to 400V DC although newer 800V architectures (Porsche Taycan, Hyundai Ioniq 5, Kia EV6) enable faster charging.
The inverter
The battery produces direct current (DC). The motor needs alternating current (AC) to spin. The inverter converts DC battery power into a precisely controlled AC waveform. By adjusting the frequency and amplitude of the AC waveform, the inverter controls the motor's speed and torque. This is the key to EV smoothness because the inverter can deliver any required power instantly with no mechanical lag.
The motor
UK EVs use either permanent magnet synchronous motors (PMSM) or AC induction motors. PMSMs are slightly more efficient and dominate modern designs. Induction motors are slightly cheaper to manufacture and were used in early Teslas. Both types produce torque from zero rpm and stay efficient up to 18,000 to 20,000 rpm. The huge usable rev range is why EVs only need a single-speed gear.
The reduction gear
The motor connects to the drive wheels through a fixed-ratio reduction gear (typically 9:1 or 10:1). The motor spins 9 to 10 times faster than the wheels. At 70 mph the wheels turn around 800 rpm and the motor turns around 7,500 rpm. There is no clutch and no shift between ratios. The whole assembly is much smaller and lighter than a multi-speed gearbox.
Regenerative braking
When you lift off the accelerator or press the brake, the motor controller reverses the energy flow. The motor acts as a generator (converting wheel rotation back into electricity). The recovered energy flows back through the inverter into the battery. The car slows because the motor is taking energy away from the wheels. Regen braking recovers around 60 to 70 percent of the energy that would otherwise be lost as heat in conventional brake pads.
The 12V system
EVs also have a small 12V auxiliary battery (similar to a petrol car's). This powers the computers, lights, infotainment and the contactors that connect the high-voltage battery to the rest of the car. The 12V battery is recharged from the main traction battery while driving via a DC-DC converter. The 12V system is needed because most automotive electronics are designed for 12V operation across the industry.
Main components of a UK EV drivetrain
What happens when you press the EV accelerator
Driver input registered
Throttle pedal sends signal to motor controller. The signal indicates how much torque the driver is requesting.
Battery delivers DC current
High-voltage battery pack supplies DC current sized to the controller's request. Current flows through high-voltage cabling to the inverter.
Inverter generates AC waveform
DC current converts into AC waveform with frequency and amplitude shaped to deliver the requested torque. The inverter is the brain of the EV.
Motor produces torque, wheels turn
AC current creates a rotating magnetic field that turns the rotor. Torque transfers through the reduction gear to the wheels. The car accelerates.
Key facts about how UK EVs work
Battery powers everything
The lithium-ion traction battery is the source of all energy. Range depends on battery capacity and efficiency.
Inverter is the brain
The inverter converts DC to AC and controls the motor. Most EV failures trace to inverter or controller issues, not the motor itself.
Motor produces torque
Electric motors produce torque from zero rpm and stay efficient across a wide rev range. No multi-speed gearbox needed.
Regen recovers energy
Regenerative braking recovers around 60 to 70 percent of energy that would otherwise be lost. Major contributor to EV efficiency.
Petrol car drivetrain
- Fuel tank stores chemical energy
- Engine burns fuel to make heat
- Heat converts to motion (20 to 25 percent efficiency)
- Multi-speed gearbox needed
- Exhaust removes combustion gases
- 200+ moving parts total
EV drivetrain
- Battery stores electrical energy
- Inverter converts DC to AC
- Motor converts electricity to motion (85 percent efficiency)
- Single-speed reduction gear sufficient
- No exhaust system needed
- Around 20 moving parts total
Understanding how EVs work helps with the buying decision. The wider EV Charger Guidance hub covers home charger install, running cost, the buying decision and the practical questions UK drivers ask about everyday EV ownership.
If you want more on what EVs do not have, our guide on do electric cars have engines covers the engine vs motor distinction. The transmission detail is in do electric cars have gears. For battery longevity see how long do electric car batteries last.
Common questions
Why are EV motors more efficient than engines?
What is the difference between AC induction and permanent magnet motors?
Why is the inverter so important?
Do EVs use the brakes at all?
What happens to the energy when an EV slows down?
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