How Do Electric Bikes Work? The Parts and What Each One Does

October 29, 2026

Rider in a helmet at the curb on a commuter e-bike, reaching for the handlebar display, the frame battery visible

How do electric bikes work? A battery stores the energy, sensors tell a controller that you are pedalling (and on some bikes how hard), and the controller sends power to a motor in a wheel hub or between the pedals. A throttle, if fitted, adds power without pedalling, and a display shows your speed and assist mode. The e-bike rules in Ontario, Quebec, B.C. and Alberta cap the motor at 500 W and end its help at 32 km/h.

Rules, safety advice and brand figures checked October 2026 (sources at the end). This is general information, not legal advice.

How do electric bikes work, step by step

You pedal or press the throttle. A throttle, on bikes that have one, runs the motor whether or not you pedal.
Sensors report to the controller. Bosch, which makes e-bike drive systems, says its three sensors measure pedal power, cadence and speed more than 1,000 times a second.
The motor's help is set. Bosch says its motors give support depending on your effort, your speed and the riding mode. In Bosch's Turbo mode, the drive unit gives up to 340% of your own power: pedal with 100 W and the motor adds up to 340 W for a short time.
The battery feeds the motor, which adds its push from a wheel hub or from between the pedals.
The help stops when you stop pedalling, release the throttle or brake, as B.C.'s regulation requires. The e-bike rules covered here also end it at 32 km/h or lower.

E-bike parts and what each one does

Part	What it does	What to check when buying
Battery	Stores the energy; capacity in watt-hours is volts × amp-hours	Volts, amp-hours and watt-hours; removable or not; ANSI/CAN/UL 2849 compliance
Charger	Recharges the battery	That one comes with the bike; a replacement should come from the original maker, with compatible voltage and current and a CSA, cUL or cETL mark
Controller	Takes pedal and speed signals and sets the motor's power; cuts it when you brake	How many assist levels there are, and how assistance starts and stops
Motor	Adds its push from a wheel hub or from between the pedals	Where it sits, its continuous rating in watts and its torque in newton-metres (N·m)
Pedal sensor	Detects pedalling (cadence) or measures how hard you push (torque)	Which type the listing names
Display and buttons	Show your speed and assist mode, and on some systems the range left	How you change assist levels while riding
Throttle	Runs the motor whether or not you pedal	Whether you want one, and whether your province and e-bike class allow it
Brakes and motor cut-off	Stop the bike; cut-off switches stop the motor when you brake	Motor cut-off levers or sensors

Battery and charger: where the energy comes from

Battery capacity is listed in watt-hours (Wh): volts times amp-hours, the formula the Canadian Air Transport Security Authority gives. Worked example, not a measurement: the 48 V, 15 Ah battery on the EUNORAU META26 1.0 holds 48 × 15 = 720 Wh. Compare battery sizes in our long-range e-bikes.

Health Canada's advisory on the lithium-ion batteries found in e-bikes says to use the battery that came with your e-bike, to replace it only with original parts from the maker or dealer, and never to modify it. Health Canada and Transport Canada recommend e-bikes and batteries that comply with ANSI/CAN/UL 2849, the safety standard for e-bike electrical systems. Our e-bike battery replacement guide explains how to match a new pack.

The City of Toronto says to use the charger that came with the device and, for an e-bike, to contact the original manufacturer if you need a replacement. A replacement's voltage and current must be compatible with your device, and chargers should carry a recognized Canadian certification mark such as CSA, cUL or cETL. Toronto also advises keeping the battery in sight while charging and unplugging it once charging is complete.

Our e-bike charger guide covers matching a charger and charging safely.

How does an electric bike work when you pedal?

Pedal assist starts at the sensor. A cadence sensor only registers that the cranks are turning, so the help at each assist level stays the same however hard you push; a torque sensor reads your pedal force and scales the help to match. Our torque vs cadence sensor guide compares how each one feels.

The META26 1.0 and the EUNORAU FAT-AWD 3.0 list a torque sensor, while EUNORAU says its FAT-HD 2.0 uses cadence-sensing assist. If a listing doesn't name its sensor, ask through our contact page.

Hub motor or mid-drive: where the push comes from

Bosch describes a hub motor as integrated into the rear wheel, and a mid-drive motor as mounted centrally on the bottom bracket, where the pedal cranks turn. The FAT-AWD 3.0 has a hub motor in each wheel, and EUNORAU says a switch picks the rear, the front or both. Our hub motor vs mid-drive guide compares how each climbs, wears and gets serviced.

Some spec sheets add a peak figure: EUNORAU lists the FAT-HD 2.0 at 1,000 W and says its motor makes over 1,500 W at peak. B.C. and Alberta add up the continuous ratings of all motors, and the FAT-AWD 3.0 lists two 500 W hub motors, 1,000 W in total (see our dual-motor e-bikes).

Throttle vs pedal assist

B.C.'s regulation calls a throttle an accelerator controller: equipment that makes the motor propel the bike "regardless of whether the operator is pedalling". Quebec's SAAQ says electric assistance "may be activated by the pedals or accelerator control".

Pedal assist adds to your own effort, at the level your assist mode sets, and works only while you pedal: B.C. and Alberta require the motor to stop when you stop pedalling. A throttle moves the bike whether or not you pedal, and B.C. requires its motor to stop when you let go or brake. Whether a throttle is allowed depends on your province and class; see our e-bike laws by province.

What limits an e-bike's assisted speed?

Motor help ends at a speed the maker sets. Bosch's Canadian spec table, for example, lists a maximum supported speed of 25 or 32 km/h for each of its drive units. The rules set the ceiling: 32 km/h in all four provinces covered here, or 25 km/h for a B.C. light e-bike. Past that, Quebec's SAAQ says, you go faster only "through the cyclist's muscle power on a flat surface".

Ontario adds that it's illegal to modify an e-bike's motor for more power or a higher assisted speed. Real-world speed also depends on power, weight, hills and wind, which our guide to how fast e-bikes go explains.

What the rules require from each part

Pedals: working pedals in all four. Quebec says you must be able to pedal as on a regular bike without assistance.
Motor: 500 W or less (250 W for a B.C. light e-bike).
Battery and wiring: Ontario and B.C. require the battery and motor to be securely fastened and the electrical terminals insulated.
Brakes: Ontario requires two independent brakes that stop the bike from 30 km/h within 9 metres on level asphalt; B.C. sets 9 metres from 32 km/h for a standard e-bike.
Lights, reflectors and horn: Alberta requires a headlamp, tail lamp, reflectors, brakes and a horn on a power bicycle. Quebec's SAAQ says e-bike accessories must comply with the Highway Safety Code, particularly for reflectors and lights.
Weight and ID: Ontario caps an e-bike at 120 kg, battery included, and Quebec requires an identification number.

Other provinces and territories are not covered here yet; check your provincial or territorial transportation department. The FAT-HD 2.0 and FAT-AWD 3.0 are listed at 1,000 W. Bikes above 500 W or assisting past 32 km/h fall outside the provincial e-bike rules, as our e-bike laws page explains.

Frequently asked questions

Can you ride an electric bike without pedalling?

Yes, with a throttle or any other control that runs the motor without pedalling, where your province and class allow one. In B.C., a bike with one also needs a separate switch to turn the motor on and off from a normal seated position, or a mechanism that stops it engaging below 3 km/h. Alberta's definition has similar options. All three bikes named here list a throttle.

Can you pedal an electric bike without the battery?

Yes, with the motor off or the battery flat: the rules in all four provinces require working pedals. You move the full weight yourself, though; the EUNORAU META26 1.0 is listed at 31.0 kg. To ride with the battery removed, follow your bike's manual.

What does the controller do on an e-bike?

It decides how much power the motor gets. Bosch says support depends on your effort, your speed and the riding mode you pick, and B.C.'s regulation requires the help to stop when you stop pedalling, release the throttle or brake. All three bikes named here list motor cut-off levers on their brakes.

How do electric bikes work on hills?

The motor adds its push to yours. Bosch says torque, from your pedalling or the motor, decides how quickly you accelerate, and that support depends on the riding mode you choose. Spec sheets list motor torque in N·m. Where the motor sits matters too, as the hub motor and mid-drive section above explains.