BOSCH BDU3740 Drive System Drive Unit Owner’s Manual

: June 5, 2024
: Bosch

BOSCH BDU3740 Drive System Drive Unit Owner’s Manual

Introduction

About Warnings

This manual contains many DANGER, WARNING, and CAUTION indicators concerning the consequences of failure to use, assemble, maintain, store, inspect and dispose of a Bosch-equipped eBike in a safe manner.

The combination of the safety alert symbol and the word DANGER indicates a hazardous situation that, if not avoided, will result in death or serious injury.
The combination of the safety alert symbol and the word WARNING indicates a hazardous situation that, if not avoided, could result in death or serious injury.
The combination of the safety alert symbol and the word CAUTION indicates a hazardous situation that, if not avoided, could result in minor or moderate injury.

General Warnings

Read all safety warnings and all instructions. Failure to follow the warnings and instructions may result in death or serious injury.

Save all safety warnings and instructions for future reference.

The term battery pack used in these operating instructions refers to all original Bosch eBike battery packs.

WARNING

This manual contains important safety, performance and service information. Read it before you take the first ride on your new bicycle, and keep it for reference. The manual can also be found online at www.bosch-ebike.com.
This manual is intended to be read together with the separate user manual provided with your bicycle. Be sure to read all provided documents including labels on the product before your first ride.
Read ALL accompanying manuals before riding the bike for the first time. Your Bosch Drive System comes with additional manuals and documents provided by the manufacturer of the bicycle and other components. Failure to read and understand safety information can result in death or serious injury.
Take responsibility for your own SAFETY. If you have any questions or do not understand something, consult with your dealer or the bicycle or component manufacturer.
Some eBike accessories may present a choking hazard to small children. Keep these accessories away from children.

CAUTION

The Bosch Drive System adds weight to your bicycle which you may not be used to lift. Avoid injury, use proper lifting techniques.

Using your Manual

In addition to the functions outlined here, changes to software relating to troubleshooting and functional modifications may be introduced at any time.

Graphics

The bicycle shown in this manual may differ slightly from your bicycle, but will be similar enough to help you understand our instructions.
RIGHT-HAND and LEFT-HAND sides are determined by facing in the direction the bicycle will travel when going forward. When you see a broken line (——), the item referred to is hidden from view.

Operating your Bosch Drive Unit

Safety instructions

Read and understand all safety warnings and instructions. Failure to follow the below warnings could result in death or serious injury.

Save all safety warnings and instructions for future reference.
The term battery pack used in these operating instructions refers to all original Bosch eBike battery packs.

Do not attempt to change – in particular, to increase – the power of your drive or the maximum speed that it supports. Doing this may put yourself and others at risk, and you could also breach statutory regulations.
Do not make any modifications to your eBike system or fit any other products that might increase the performance of your eBike system.
Doing so will generally reduce the service life of the system and risks damaging the drive unit and the bike. You also run the risk of losing the guarantee and warranty claims on the bicycle you have purchased. By handling the system improperly you are also endangering your safety and that of other road users, thus running the risk of high personal liability costs and possibly even criminal prosecution in the event of accidents that can be attributed to manipulation of the bicycle.
Do not open the drive unit yourself. The drive unit must only be repaired by qualified personnel using only original spare parts. This will ensure that the safety of the drive unit is maintained. Unauthorized opening of the drive unit will render warranty claims null and void.
All components fitted to the drive unit and all other components of the eBike drive (e.g. chainring, chainring receptacle, pedals) must only be replaced with identical components or components that have been specifically approved by the manufacturer for your eBike. This will protect the drive unit from overloading and becoming damaged.
Remove the battery from the eBike before beginning work (e.g. inspection, repair, assembly, maintenance, work on the chain, etc.) on the eBike, transporting it with a car or airplane, or storing it. Unintentional activation of the eBike system poses a risk of injury.
Under extreme conditions, such as continuously high loads at low speed when riding up hills or carrying loads, parts of the drive unit can reach temperatures in excess of 140 °F.
After a ride, do not allow your unprotected hands or legs to come into contact with the housing of the drive unit. Under extreme conditions, such as continuously high torques at low travel speeds, or when riding up hills or carrying loads, very high temperatures may be reached on the housing.
The temperatures that may be reached on the drive unit housing are influenced by the following factors:
- Ambient temperature
- Ride profile (route/gradient)
- Ride duration
- Assistance modes
- User behavior (personal effort)
- Total weight (rider, eBike, luggage)
- Motor cover on the drive unit
- Heat dissipation properties of the bicycle frame
- Type of drive unit and type of gear-shifting
Use only original Bosch batteries that the manufacturer has approved for your eBike. Using other batteries can lead to injuries and pose a fire hazard. Bosch accepts no liability or warranty claims if other batteries are used.
Keep the magnet away from implants and other medical devices, such as pacemakers and insulin pumps. The magnet creates a field which can impair the function of implants or medical devices
Keep the magnet away from magnetic data carriers and magnetically sensitive devices. The effect of the magnets may lead to irreversible data losses.
Observe all national regulations which set out the approved use of eBikes.
Please observe all local, state and federal regulations when registering and using eBikes.

Privacy notice

When you connect the eBike to the Bosch DiagnosticTool 3 , data about Bosch drive unit (e.g. energy consumption, temperature, etc.) is transferred to Bosch eBike Systems (Robert Bosch GmbH) for the purposes of product improvement. You can find more information about this on the Bosch eBike website at www.bosch-ebike.com.

Product description and specifications

Intended use

The drive unit is intended exclusively for driving your eBike and must not be used for any other purpose.
In addition to the functions outlined here, changes to software relating to troubleshooting and functional modifications may be introduced at any time.

Technical data

Drive unit	Drive Unit Performance Line CX

Product code

Continuous rated power

| W| BDU3740

__BDU3741
250

Torque at drive, max.| Nm| 85
Rated voltage| V=| 36
Operating temperature| °F| 23 to 104
Storage temperature| °F| 50 to 104
Protection rating| | IP54
Weight, approx.| lbs| 6.6

The Bosch eBike system uses FreeRTOS
(see http://www.freertos.org).

Bicycle lightsA)

Voltage approx.B)	V=	12
Maximum power

Front light

| W| 17.4

Rear light

| W| 0.6

A) Depends on legal regulations, not possible in all countryspecific models via the eBike battery
B) When changing the bulbs, ensure that they are compatible with the Bosch eBike system (ask your bicycle dealer) and are suitable for the specified voltage. Bulbs must only be replaced with bulbs of the same voltage.

Inserting a bulb incorrectly can cause it to blow.

Assembly

Checking the speed sensor (see figure A)

Assembly

Speed sensor a)
Spoke magnet
CenterLock magnet b)
Rim magnet

a) Different sensor shape and installation position possible
b) a different installation position is possible

Speed Sensor (slim)
The speed sensor (1) and its CenterLock magnet (3) or spoke magnet (2) are mounted ex works in such a manner that the magnet, after a turn of the wheel, moves past the speed sensor with a clearance of at least 2 mm, yet no more than 15 mm.
The correct distance between the magnet and sensor must be maintained (see figure A ) if design changes are made.
Notes: Ensure that you do not damage the sensor or sensor bracket when fitting or removing the rear wheel.
When changing a wheel, make sure that the sensor cable is routed so that it is not under tension and has no kinks.
The CenterLock magnet (3) can only be removed and reinserted up to five times.

Rim magnet
When installing a rim magnet, no sensor is required to detect a wheel turn. The drive unit itself detects when the magnet is close to it and calculates the speed and any other data required from the frequency of the emergence of the magnet field.
Since the drive unit is sensitive to magnetic fields, avoid other magnetic fields in the vicinity of the drive unit (e.g. magnetic clipless pedals, magnetic cadence sensors, etc.) in order to prevent disruption to the drive unit.

Operation

An operating unit is required for the starting operation of the eBike system. Observe the starting operation for the eBike system and drive unit control in the operating unit operating instructions.

Notes on cycling with the eBike system
Note: The eBike system always starts with assistance level OFF.

When does the eBike drive work?
The eBike drive assists your cycling only when you are pedaling. If you do not pedal, the assistance will not work. The motor output always depends on the pedaling force you apply

If you apply less force, you will receive less assistance than if you apply a lot of force. This applies irrespective of the assistance level.
The eBike drive automatically switches off at speeds over 20 mph. When the speed falls below 20 mph, the drive automatically becomes available again.
An exception applies to the push assistance function, in which the eBike can be pushed at low speed without pedaling. The pedals may rotate when the push assistance is in use.

You can also use the eBike as a normal bicycle without assistance at any time, either by switching off the eBike system or by setting the assistance level to OFF. The same applies when the battery is drained.

Interaction between the eBike system and gearshifting

The gear-shifting should be used with an eBike drive in the same way as with a normal bicycle (observe the operating instructions of your eBike on this point).
Irrespective of the type of gear-shifting, it is advisable to briefly stop pedaling when changing gear. This will facilitate the gear change and reduce wear on the powertrain.
By selecting the correct gear, you can increase your speed and range while applying the same amount of force.

Gaining initial experience
We recommend that you gain initial experience with the eBike away from busy roads.
Test the various assistance levels, beginning with the lowest level. As soon as you feel confident, you can ride your eBike in traffic like any other bicycle.
Test the range of your eBike in different conditions before planning longer and more demanding trips.

Influences on range

The range is affected by a number of factors, such as:

Assistance level
Speed
Gear shifting behavior
Tire type and tire pressure
Age and condition of the battery
Route profile (gradients) and conditions (road surface)
Headwind and ambient temperature
Weight of eBike, rider and luggage

For this reason, it is not possible to predict the range accurately before and during a trip. However, as a general rule:

With the same assistance level on the eBike drive:
The less energy you need to exert in order to reach a certain speed (e.g. by changing gears optimally), the less energy the eBike drive will consume and the higher the range per battery charge will be.
The higher the selected assistance level under otherwise constant conditions, the smaller the range will be.

Maintenance/Cleaning

WARNING

Do not open any of the components. Service should only be carried out at an authorized Bosch eBike dealer. Failure to follow above warning can cause death or serious injury. Refer to your bicycle manual or component manual for all nonBosch drive system components.
Always remove the battery pack before performing any bicycle inspection, maintenance or repair. Failure to remove the battery pack before performing bicycle inspection, maintenance or repair can lead to serious injury.
If you suspect that something is loose, do not ride your bike. See your Bosch eBike dealer, only a qualified service provider should perform work on your Bosch Drive System. All nuts, bolts, screws require the correct tightening force. Too little force and the fastener may not hold securely. Too much force and the fastener can strip threads, stretch, deform or break. Either way, incorrect tightening force can result in component failure, which can cause you to lose control and fall.
If replacing your battery, buy only a genuine Bosch battery pack from an approved source.
See your Bosch eBike dealer for original Bosch parts.
Always switch the battery pack off, when inserting or removing it from the holder. Never attempt to insert or remove the battery pack while riding the bike.
Do not charge or use your eBike in any area with a potentially explosive atmosphere, such as at a fueling area, or in areas where the air contains chemicals or particles (such as grain, dust, or metal powders). Obey all signs and instructions.
Do not submerge your eBike components in water, or wash with pressurized hose. Your Bosch drive unit is designed to be water tight to rain water or non-pressure hose washing.
Note down the manufacturer and the number of the key. In case of loss of the keys, please refer to an authorised Bosch eBike dealer. Please provide the name of the manufacturer and the number of the key.
Do not paint any components of the Bosch drive system as they may cause premature failure of the component.

When changing the bulbs, ensure that they are compatible with the Bosch eBike system (ask your bicycle dealer) and are suitable for the specified voltage. Bulbs must only be replaced with bulbs of the same voltage.

Taking care of your eBike

Please observe the operating and storage temperatures of the eBike components.
Protect the drive unit, on-board computer and battery against extreme temperatures (e.g. from intense sunlight without adequate ventilation). Extreme temperatures can cause the components (especially the battery) to become damaged.
Have your eBike system checked by an expert at least once a year (including mechanical parts, up-to-dateness of system software).
Please have your eBike serviced and repaired by an authorized bicycle dealer.

After-sales service and advice on using products

If you have any questions about the eBike system and its components, contact an authorized bicycle dealer. For contact details of authorized bike dealerships, please visit www.bosch-ebike.com.
Please contact an authorized bicycle dealer if the battery is no longer working.

Cleaning

Do not submerge your eBike components in water, or wash with pressurized hose. Your Bosch drive unit is designed to be water tight to rain water or non-pressure hose washing.

Keep all components of your eBike clean, especially the battery-pack contacts and corresponding holder contacts. All components including the drive unit may not be immersed in water or cleaned with a high-pressure cleaner. Clean them carefully with a soft, damp cloth (using only mild soap and water).

Disposal

The drive unit, on-board computer incl. operating unit, battery, speed sensor, accessories and packaging should be disposed of in an environmentally correct manner.
Do not dispose of eBikes and their components with household waste.

Please return Bosch eBike components that are no longer usable to an authorized bicycle dealer.
Subject to change without notice.