BAFANG MM G31.250 User manual

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Max Drive System User Manual
Suzhou Bafang Electric Motor Science-Technology Co., Ltd.
www.szbaf.com

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CONENTS
IMPORTANT NOTICE ................................................................................................................................... 4
FOR YOUR SAFETY ...................................................................................................................................... 5
1. DRIVE UNIT.............................................................................................................................................. 7
1.1 ADVANTAGES .......................................................................................................................................... 7
1.2 SCOPE OF APPLICATION ......................................................................................................................... 7
1.3 NAMING RULE......................................................................................................................................... 7
1.4 MAIN TECHNICAL PARAMETERS ........................................................................................................... 8
1.5 DRIVE UNIT STRUCTURE AND DIMENSIONS........................................................................................... 8
2. SYSTEM INSTALLATION.................................................................................................................... 10
2.1 LIST OF TOOLS TO BE USED.................................................................................................................. 10
2.2 COMPONENT NAMES............................................................................................................................. 11
2.3 DISPLAY INSTALLATION (DP C01.RS232.7 )....................................................................................... 11
2.4 AUXILIARY KEYPAD INSTALLATION.................................................................................................... 13
2.5 BATTERY SLIDEWAY INSTALLATION................................................................................................... 14
2.6 EXTERNAL SPEED-DETECING SENSOR INSTALLATION........................................................................ 15
2.7 DRIVE UNIT INSTALLATION ................................................................................................................. 17
3. SYSTEM CABLING................................................................................................................................ 23
3.1 LINK THE BATTERY CABLE TO THE DRIVE UNIT................................................................................ 23
3.2 LINK THE EXTERNAL SPEED-DETECTING SENSOR TO THE DRIVE UNIT ............................................ 23
3.3 LINK THE EB-BUS TO THE DRIVE UNIT.............................................................................................. 24
3.4 LINK THE HEADLIGHT CABLE TO THE DRIVE UNIT............................................................................ 24
3.5 LINK THE TAILLIGHT TO THE DRIVE UNIT.......................................................................................... 24
4. INSTALLATION OF THE FRONT CHAINWHEEL AND THE CHAIN COVER......................... 25
4.1 INSTALLATION OF THE CHAINWHEEL (WITHOUT A CHAIN COVER).................................................... 25
4.2 CHAIN COVER INSTALLATION (OPTIONAL)......................................................................................... 26
4.3 CRANK INSTALLATION ......................................................................................................................... 31
5. BATTERY ................................................................................................................................................ 33
5.1 USE THE BATTERY PROPERLY ............................................................................................................. 35
5.2 CHARGE THE BATTERY ........................................................................................................................ 35
5.3 BATTERY CAPACITY DISPLAY.............................................................................................................. 35
5.4 BATTERY HEALTH INDICATION ........................................................................................................... 36
5.5 BATTERY INSTALLATION...................................................................................................................... 36

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6. DISPLAY.................................................................................................................................................. 38
6.1 SPECIFICATIONS AND PARAMETERS OF THE DISPLAY ........................................................................ 38
6.2 APPEARANCE AND DIMENSIONS........................................................................................................... 38
6.3 FUNCTION OVERVIEW AND KEY DEFINITIONS.................................................................................... 38
FUNCTION OVERVIEW ....................................................................................................................................... 38
ITEMS TO BE SHOWN ON THE DISPLAY............................................................................................................. 39
KEY DEFINITIONS .............................................................................................................................................. 40
6.4 NORMAL OPERATION ........................................................................................................................... 40
ASSIST MODE SELECTION ................................................................................................................................. 40
DISTANCE MODE AND SPEED MODE SWITCH................................................................................................... 41
HEADLIGHT/BACKLIGHT SWITCH.................................................................................................................... 41
WALK ASSISTANCE MODE................................................................................................................................. 42
BATTERY LEVEL INDICATION ........................................................................................................................... 42
6.5 PARAMETER SETTING........................................................................................................................... 43
ITEMS TO BE SET:............................................................................................................................................... 43
SETTING PREPARATION..................................................................................................................................... 43
DATA RESET:..................................................................................................................................................... 44
KM/MILE:.......................................................................................................................................................... 44
LIGHT SENSITIVITY:.......................................................................................................................................... 45
BACKLIGHT BRIGHTNESS:................................................................................................................................. 45
AUTOMATIC OFF TIME:..................................................................................................................................... 45
MAINTENANCE WARNING (INACTIVE BY DEFAULT):........................................................................................ 46
ITEMS FOR SECONDARY SETTING:.................................................................................................................... 46
PASSWORD INPUT:............................................................................................................................................. 46
SPEED LIMIT CHANGE:...................................................................................................................................... 47
BATTERY COMMUNICATION:............................................................................................................................ 47
6.6 ERROR CODE DEFINITIONS.................................................................................................................. 49
FAULT ALERT INTERFACE....................................................................................................................... 50
7. LIST OF MATERIALS............................................................................................................................... 51
8. AFTER-SALES AND WARRANTY POLICY ..................................................................................... 53

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Important Notice
The Dealer Manual is to be used by professional e-bike mechanics。Users who have
not received training on electric bicycle assembly shall not attempt to assemble parts
and components by following the Dealer Manual.
If you doubt about any part of the manual, do not install the product. Please consult the
local sales office or an electric bicycle dealer for help.
Make sure to read all of the installation manuals delivered with the product.
Do not disassemble or modify the product unless specified by the Dealer Manual.
The Dealer Manual is available on our website (www.szbaf.com).
The dealer shall observe laws and regulations of the region, the state and the country
where the product is sold.
Make sure you have read this user manual carefully in order to use the product properly.

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For your Safety
Warning
When installing this product, be sure to follow the instructions given
in the user's manual.
It is recommended that you use only genuine Bafang parts at these times. The bicycle may
suddenly fall over and serious injury may result if bolts and nuts are left loosened, or the
product is damaged or improperly adjusted.
When performing maintenance operations (for example parts replacement), be sure to wear
goggles or eye patches to protect your eyes.
Please refer to the manual provided together with the product for information uncovered
by this manual.
After reading the user's manual carefully, keep it in a safe place for later reference.
You must be aware that:
Do not give too much of your attention to the cycle display while riding, otherwise you
may fall off the bike.
Check that the wheels are securely installed to the bicycle before commencing riding. If
the wheels are not securely installed, the bicycle may fall over and serious injury may
result.
When riding a pedal-assisted electric bicycle, make sure that you are fully familiar with
the starting-off characteristics of the bicycle before riding it. If the bicycle starts off
suddenly, accidents may result.
Make sure the bicycle lights illuminate before riding at night.
Instructions on bicycle installation and maintenance
When cabling the product or installing the parts onto the bicycle, be sure to disconnect the
battery. Not doing so may result in electric shock.
When installing this product, be sure to follow the instructions given in the user's manual.
If bolts and nuts are left loosened or the product is damaged, the bicycle may suddenly fall
over and serious injury may result.
The frequency of maintenance will vary depending on the riding conditions. Periodically
clean the chain using an appropriate chain cleaner. Do not use alkaline or acidic cleaning
agents to remove rust under any circumstances. If such cleaning agents are used, they may
damage the chain and serious injury may result.

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Note
You must be aware of the following precautions:
Please follow instructions given in the user manual for your riding safety.
Examine the battery charger regularly for damage, especially the cable, plug and enclosure.
If the battery charger is damaged, it must not be used until it has been repaired.
Please follow the guidance given by the safety supervisor or the instructions indicated in
the manual when using the product. This product is not intended for use by persons
(including children) with reduced physical, sensory or mental capabilities, or lacking
experience and knowledge, unless they have been given supervision or instruction
concerning use of the product by a person responsible for their safety.
Do not allow children to play near the product.
Please consult the nearest dealer for any errors or problems.
Do not modify the system. Doing so may lead to malfunction of the system.
For information on product installation and adjustment, please consult your dealer.
The product is designed to be fully waterproof to withstand wet weather riding conditions.
However, do not deliberately immerse it into water.
Do not clean the bicycle in a high-pressure wash. If water gets into any of the components,
operation problems or rusting may result.
When shipping the product with a high-speed vehicle in a rainy day, remove the battery
and put it in a safe place to stop it from getting wet due to the rain.
Handle the product carefully, and avoid subjecting it to any strong shocks.
Some important information given in the user manual may also be found in product labels.
When buying a spare key for the battery, be sure to provide the number on the battery key.
Please keep the number in your mind or your notebook.
Use a wrung-out damp cloth to clean the battery enclosure.
For any questions regarding the maintenance and use of the product, please contact the
dealer where you bought the product.
Natural wear and tear due to normal use and aging is not within our scope of quality
guarantee.
Please contact the seller for software updates (if any). The newest information on software
will be available on the home page of Bafang website: www.szbaf.com

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1.Drive Unit
1.1 Advantages
The controller ensures system safety with the fed-back torque signals and dual speed
signals (pedal assist signals and external bicycle speed-detecting signals);
With a high starting torque and a maximum torque of no smaller than 80N.m, it is
especially suitable for climbing;
High efficiency, low power consumption, and longer riding distance.
Low noise and smooth operation.
1.2 Scope of Application
The drive unit can work properly in the following environmental conditions:
Ambient temperature: (- 20- + 55) ℃;
Relative humidity: (15-95) % RH;
Note: The product can’t work normally if there is any major corrosive gas, any medium that
affects the product’s electrical insulation properties or any high-intensity magnetic field.
1.3 Naming Rule
Naming Rule:
The nameplate is engraved on the shell, showing such information as follows:
MM G33.350 14010001
(1) 36V 250W (2)
(3) (4)
(1)MM G33.250─Name of the drive unit;
(2)1401─Date of production, January 2014 in this example;
0001─Production serial number, ranging from 0000 to 9999; 0001 is the production
serial number of the first motor.
(3)36V─Rated motor voltage;
(4)250W─Rated motor power.

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1.4 Main Technical Parameters
Rated voltage (DCV)
36
43
Rated power(W)
250
350
250
350
Rated efficiency (％)
≥80％
Rated rotating speed(rpm)
100±5
Maximum torque(N.m)
≥80
Chain wheel
36T (recommended), 38T (optional), 42T (optional)
Optional chain cover
full chain cover / P-shaped chain cover
Weight (Kg)
3.9
Sensors
pedal assist speed sensor, pedal assist torque sensor and
bicycle wheel speed sensor and temperature sensor
Noise (dB)
＜55
Working environment
-20℃～55℃
Dust-proof/ water-proof
grade
IP66
Certification
CE ROHS/ EN14766/ EN14764/ REACH
Other functions
optional bluetooth module, gear sensor module, DC 500mA/
6V headlight and taillight module, reprogramming function
1.5 Drive Unit Structure and Dimensions

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2. System Installation
2.1 List of Tools to be Used
Components
Use of the Tools
Tools
Display
To fix the screw M4
Internal hexagonal
wrench
Drive Unit
To fix the chain wheel
retaining ring
A special tool
To remove the chain wheel
retaining ring
Plier for the retaining
ring
To fasten M4 screws which
are used to fix the chain cover
binder plate onto the drive unit.
Cross screwdriver
To fasten M6 bolts and nuts
which are used to fix the
frame adapter with the drive
unit.
Internal hexagonal
wrench
To fasten the crank mounting
screw M8.
Internal hexagonal
wrench
Speed-
detecting
Sensor
To install the magnetic steel.
Straight screwdriver
To fix the M5 screw for the
speed-detecting sensor.
Cross screwdriver
Battery
To fix M5 screws used to
fasten the battery pack onto
the carrier.
Internal hexagonal
wrench
The tool used to install the retaining ring onto the spline shaft.
Tool code：GZ-MM G31-5025)

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2.2 Component Names
A. Drive unit
B. Front chain
wheel
C. External
speed-
detecting
sensor
D. Battery
E. Auxiliary
keypad
F. Display
2.3 Display Installation (DP C01.RS232.7 )
One or two rubber clamping rings may be needed depending on the diameter of
the handlebar (the applicable handlebar specifications are Φ22.2, Φ25.4 and
Φ31.8). Open the left or right display clamp, and insert one or two clamping rings
into the right position of the display clamp as shown in the picture above.
A. a rubber clamping ring
(whose inner diameter is
Φ22.2 or Φ25.4)
Left and right display
clamps for theΦ22.2
handlebar:
Left clamp -
2316020400017
Right clamp -
2316020400018
Left and right display
clamps for theΦ25.4
handlebar:
Left clamp -
2316020400007
Right clamp -
2316020400008
(E)
(D)
(B)
(A)
(F)
(C)

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Insert the clamping ring(s) to each of the two display clamps and mount
them onto the handlebar. Use an internal hexagonal wrench to fasten the
left and right clamps onto the handlebar.
B. display clamp
C. hexagon socket head cap
screws M4*8
Adjust the angle of the display so that you can easily see the display
screen when riding. After the angle has been adjusted, tighten the screws
to the specified torque.
Tightening torque: 1N.m
Tool:

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2.4 Auxiliary Keypad Installation
Open the auxiliary keypad and assemble it onto a position that is easy for
operation. Adjust the angle of the auxiliary keypad to ensure that the
keypad is easy to see seen during riding.
(Applicable to the handlebar whose external diameter is Φ22.2mm)
A. keypad clamp
Fix the keypad onto the handlebar with a screw. Then tighten the fixing
screw with an internal hexagonal wrench.
Tightening torque: 1N.m
B. hexagon socket head cap
screw M3*8
Tool:

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Match the female connector at the display with the male connector at the
EB-BUS as shown in the picture above.
H. female connector at the
display
h. male connector at the EB-
BUS
2.5 Battery Slideway Installation
Align the mounting holes of the carrier with the mounting holes of the
battery slideway. Fasten the battery slideway onto the battery carrier with
hexagon socket head screws (M5).
Tightening torque: 2N.m
A. hexagon socket head cap
screw (M5)
Tool:

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2.6 External Speed-detecting Sensor Installation
Before installing the speed sensor, please make sure the gap between the
speed-detecting sensor and the magnetic unit is between 5 to 25 mm.
A. external speed-detecting
sensor
B. magnetic unit
C. spokes
D. chain stay
If the gap is within the specified range, use the mounting bolt to fix the
speed sensor.
If the gap is over 25mm, please put spacers between the sensor and the
chain stay boss to reduce this gap.
Tightening torque: 1.5 - 2 N·m
A. Dust cap
(2301030000003 )
B. mounting bolt M5*12
C. external speed-detecting
sensor
D. sensor bracket (chain stay
boss)
Tool:

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Arrange the speed sensor and the magnetic unit as shown in the picture
above. When installing the magnetic unit, make sure its center faces the
center of the speed sensor’s induction zone.
Arrange the speed sensor and the magnetic unit as shown by the picture
above. Mount the magnetic unit onto a spoke with the spoke stuck in the
magnetic unit.
A. external speed-detecting
sensor
B. magnetic unit
(PS01010702/2308040000001)
C. spokes
Tighten up the magnetic mounting nut with a straight screwdriver.
Tightening torque: 1.5 - 2 N·m
D. Magnetic mounting nut
(PS01010701/2327000000003)
Tool:

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2.7 Drive Unit Installation
Cables should be arranged in advance according to the bicycle type and the
cabling system before installing the drive unit.
A. battery cable
B. taillight cable
C. external speed-
detecting sensor cable
D. headlight cable
E.EB-BUS
Align the three mounting holes of the drive unit with the mounting holes in the
bicycle frame.
Note:
Pay attention to the outgoing directions of the cables. Please be noted that the
cables shouldn’t be squeezed by the drive unit.
A. mounting holes
B. drive unit
(MM G33.350)

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Insert, from the right, special M6 nuts into the mounting holes in the bicycle frame and
the drive unit.
C.M6 nuts
(1401080000101)
Insert, from the left, the M6 bolts into the bicycle frame so that they will come to
contact with the nuts. Tighten bolts onto nuts with a specified torque.
Tightening torque: 18- 20 N·m
D.M6 bolts
(1401080000099)
Tool:
Open the terminal box and get ready to link female connectors with male connectors.
Push the lower part of each of the male buckles on the cabling box body (in the
A. upper cover of
the cabling box
B. the cabling box
body

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direction as show by the arrows in the picture above) to release the female buckles on
the upper cover. Push the upper cover in the direction of moving towards Buckle 3 to
fully open the upper cover.
Open the cabling box, link all cables to the drive unit and put all connectors in the
cabling box according to the cabling diagram printed on the upper cover of the cabling
box (see C in the picture above).
After matching all male connectors with female connectors, cover the cabling box
with the upper cover and thread the cables through cable clips (D in the picture above)
following the principle of "upper thin cables and lower thick cables" to ensure that the
cables are neatly arranged.
C. cabling layout
(2307070000001)
D. cable clips
(1401300000001)

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The picture above shows how the drive unit looks like when the cables are
re-arranged with the help of the two cable clips.
Please be noted that all cables must thread through the cable clips after
going out of the cabling box.
Push the buckle on the drive unit cover into the slot on the frame adapter.
A. frame adapter
B. drive unit cover
1333000000001