How electric bikes work: motors, batteries and pedal assist

An electric bike combines a pedal bicycle with a battery, motor and controls that provide assistance. You still steer, brake and choose a suitable gear. On a pedal-assist system, sensors tell the controller when to support your pedalling; the assistance setting changes the help available.

Understanding those separate jobs makes a specification sheet easier to read. A bigger battery, a different motor position and more gears each change a different part of the ownership decision.

Follow the power through the bike

Battery

Stores electrical energy and supplies the system. The pack, charger and electronics need to be compatible with one another.

Sensors and controller

Provide information about riding and manage the motor's assistance. The exact response depends on the system and settings.

Motor

Adds driving force. A hub motor is located at a wheel; a mid-drive sits around the crank area and works through the bicycle's transmission.

Display and controls

Let the rider select assistance and see the information offered by that system, such as charge level or speed.

Bafang's explanation of motor locations describes the different layouts. Motor position is one part of the choice; the complete bike's gearing, weight and controls also matter.

Pedal assist and bicycle gears do different jobs

Your bicycle gears change the mechanical relationship between pedalling and wheel movement. The assistance setting changes motor support. For a hill, selecting an appropriate gear is still useful even when the motor is helping. Practise shifting and changing assistance separately so that you can recognise what each control does.

A single-speed bicycle has one mechanical gear ratio; a geared bicycle lets you change that ratio. Either layout may have several motor-assistance settings. The number of gears is therefore a separate choice from the number of assistance levels.

Some systems respond to pedal rotation; others also measure the rider's effort. A sensor label describes how the system obtains information, but a short trial is more useful for judging whether starting, slowing and re-starting feel manageable for you.

Read watts, watt-hours and torque separately

Watts (W) express power. Watt-hours (Wh) express energy capacity. Newton-metres (Nm) express torque. None is a substitute for the other, and none gives a complete riding result by itself.

The TXED Trail lists a 36V 13Ah battery: 36 × 13 = 468Wh nominal. The Maverick lists 48V 15Ah: 48 × 15 = 720Wh nominal. These calculations make capacity easier to compare across different voltages. They do not predict the mileage of a particular trip.

Know which riding category you are choosing

For an EAPC, current GOV.UK rules require usable pedals, no more than 250W continuous rated motor power and assistance ending at 15.5mph. A throttle needs its own configuration and approval checks. Read the UK legal buying guide for the full requirements.

Turn the explanation into a useful shortlist

Choose a bike whose controls you can use comfortably, whose weight you can manage and whose charging arrangement works at home. Compare the Trail and Maverick using their complete specifications. When the bike arrives, follow its supplied instructions and use our first-ride guide to practise in a quiet permitted place.