When an e-bike cuts out mid-ride, we immediately think of a serious breakdown. In most cases, however, it's a "logical" problem: a sensor losing signal, a battery not properly connected, a protection mechanism activating, or simply the normal behavior of the assistance system above a certain speed.

The aim of this guide is to clearly answer the question why my electric bike shuts off while riding , and to give you a simple method to identify the cause, without going into unnecessary disassembly.

1) Why does the assistance on my electric bike stop mid-ride?

There are two main types of banknotes:

A) “Normal” shutdown (expected behavior)
On an e-bike of the "pedelec/EPAC" type, the assistance is designed to decrease and then cut off when the speed approaches 25 km/h (and it also stops if you stop pedaling). This is standard bike operation, not a malfunction.

B) “Abnormal” interruption (intermittent or repeated)
Here, we generally look in the following direction:

• of the speed sensor (misaligned magnet, lost signal),

• battery (low, cold, improperly connected),

• of a brake contact (the bike “thinks” you are braking),

• from overheating (thermal protection),

• due to a loose connection in the wiring.

2) The most frequent causes when an electric bike shuts off while riding

The speed sensor loses signal (very common).

When the speed sensor loses its connection to the magnet, the assistance may be limited or cut out, sometimes with the speed displayed on the screen becoming inconsistent. Bosch provides an example of a speed-related error indicating that power may be limited and recommends checking that the rim magnet is securely attached.
If you have a cut that appears after an impact, a cobblestone road or transporting the bike, this is a priority track.

Battery is weak, cold, or improperly connected

A very low battery (or one that's cooled down in winter) can cause voltage drops under load, and the system may protect itself by cutting off the assistance. Another common issue: a battery that isn't fully locked in place → micro-cuts in voltage on bumps.

Brake contact (safety cut-off)

Many e-bikes automatically cut off the motor as soon as the bike detects braking (a safety feature). If a brake sensor is incorrectly adjusted, wet, or if a lever has play, the assistance may cut out even with the slightest movement.

Overheating or overloading (especially uphill)

When going uphill, with a heavy load (cargo, passenger, steep inclines) and high assistance levels, the motor and/or controller can overheat. Some systems then reduce assistance, or even temporarily shut it off, to allow it to cool down.

Loose connection / connector / humidity

A slightly loose connector (display, motor, battery) can be enough to cause intermittent power cuts, especially with vibrations. If the cuts occur after rain, washing, or damp storage, inspecting the connectors and having them checked is advisable.

3) Is it normal for the motor to cut out at 25 km/h on an e-bike?

Yes. On a “25 km/h” e-bike, the assistance is designed to be progressively reduced and then cut off as you approach 25 km/h , and it should not propel without pedaling.
If your bike only "cuts out" at 25 km/h but runs perfectly below that speed, this is very likely normal behavior.

4) Can a low battery cause an electric bike to shut down mid-journey?

Yes, especially when you demand a lot of power: starting on a hill, maximum assistance, heavy load, headwind. Under these conditions, the voltage can drop momentarily, and the system may go into protection mode.

In practice: if your battery life drops quickly and the cut-outs happen mainly when you push hard, start by testing a ride with reduced assistance mode, climbing more smoothly (higher cadence), and checking that the battery is perfectly locked.

5) My electric bike shuts off when I go uphill: what could be the cause?

The coastline combines several factors that put stress on the system: high power demand, heat, voltage drop, and vibrations. The most likely causes are:

• Low/cold battery + high demand

• overheating (temporary shutdown),

• speed sensor that loses signal due to vibrations (magnet/sensor).

If you see a code on the screen, the quickest thing to do is read it and then perform the initial checks. The e-bike troubleshooting guide helps you link the codes to the necessary checks before taking your bike to a repair shop.

6) How can I prevent my electric bike from shutting off while I'm riding?

Without getting into the complexities, here are the actions that eliminate a large portion of the cuts:

• Check that the battery is properly engaged/locked (and that nothing “moves” in its housing).

• Visually check the speed sensor and the magnet (alignment, attachment, cleanliness).

• Avoid heavy efforts at very low cadence uphill (prefer a higher cadence, a lighter gear).

• In case of repeated cut-outs or codes, perform a proper diagnosis (rather than "trying at random").

• If needed, rely on a service point: the electric bike motor problem page allows you to identify partners/testing and after-sales service points.

FAQ

Why does the assistance on my electric bike stop mid-ride?

This could be normal (speed close to 25 km/h), or it could be a protection mechanism/signal loss (speed sensor, battery, brake, overheating, connection). A good starting point is to check if a code appears and then follow a troubleshooting procedure via the "Why does my e-bike shut off while riding?" section .

Is it normal for the motor to cut out at 25 km/h on an e-bike?

Yes. On a standard EPAC/pedelec, the assistance is progressively reduced and then cut off as you approach 25 km/h.

Can a low battery cause an electric bike to shut down mid-ride?

Yes, especially under high demand (hills, load, maximum assistance). A weak or cold battery can trigger a protection mechanism when it experiences a voltage drop under load.

My electric bike cuts out when I go uphill: what could be the cause?

Often it's a combination of high demand, overheating, and a voltage drop, or a speed sensor that loses its signal due to vibrations. This is typically the kind of case where checking the magnet/sensor is helpful.

How can I prevent my electric bike from shutting off while I'm riding?

Ensure the battery is securely locked in place, check the sensor/magnet alignment, and increase your cadence when going uphill. If the problem persists, a workshop check is recommended at a service center listed here: electric bike motor problem .