Key-Disp KD51C User manual

Contents
Product Name and Model......................................................................................................................1
Specifications...........................................................................................................................................1
Appearance and Size.............................................................................................................................1
◆Display appearance and size................................................................................................... 3
◆Remote appearance and size...................................................................................................3
Function summary and layout.............................................................................................................. 2
◆Function Summary..................................................................................................................... 3
◆Function Layout...........................................................................................................................3
General Operation.................................................................................................................................. 4
◆Switching the E-bike System On/Off....................................................................................... 4
◆Display Interface......................................................................................................................... 4
◆Switching Push-Assist Mode On/Off....................................................................................... 4
◆Switching the Lighting On/Off...................................................................................................5
◆Assist Level Selection................................................................................................................ 5
◆Battery Indicator..........................................................................................................................6
◆Motor Power Indicator................................................................................................................6
◆Error Code Indication................................................................................................................. 7
General Settings..................................................................................................................................... 7
◆Trip Distance Clearance............................................................................................................7
◆Backlight Contrast Settings.......................................................................................................8
◆Toggle the unit km/mile..............................................................................................................8
General Parameter Settings................................................................................................................. 9
◆Wheel Diameter Settings...........................................................................................................9
◆Speed limit Settings....................................................................................................................9
Personalized Parameter Settings...................................................................................................... 10
◆Battery Power Bar Settings.....................................................................................................10
◆Assist Level Settings (optional)...................................................................................10
Assist level mode options.............................................................................................10
Assist level ratio Settings........................................................................................................ 11
◆Controller Over-current Cut Settings (optional)...................................................................12
◆Power Assistant Sensor Settings(optional)..........................................................................12
PAS Direction Settings............................................................................................................ 12
PAS Sensitivity Settings.......................................................................................................... 12
PAS Magnet Quantity Settings...............................................................................................13

◆Speed Sensor (optional)..........................................................................................................14
◆Throttle Settings (optional)......................................................................................................14
Throttle Push-assistance Enable/Disable............................................................................ 14
Throttle Level Enable/Disable................................................................................................ 14
◆System Settings (optional)......................................................................................................15
Delay Time Settings of Battery Power..................................................................................15
Max Speed Limited.................................................................................................................. 16
Push-assistance button Enable/Disable.............................................................................. 16
Slow Start Up Settings............................................................................................................ 17
◆Power-on Password Settings................................................................................................. 17
◆Power-on Password Enable/Disable.....................................................................................15
◆Power-on Password Change..................................................................................................18
◆Exit Settings...............................................................................................................................19
Recover Default Settings.....................................................................................................................19
Quality Assurance and Warranty Scope.......................................................................................... 18
ⅠWarranty....................................................................................................................................18
ⅡOthers........................................................................................................................................18
Connection Layout................................................................................................................................18
Warnings................................................................................................................................................ 19
Attached list 1 Error code definition...................................................................................................19
Attached list 2 Assist level ratio defaults.......................................................................................... 19

1
Product Name and Model
Intelligent Segment LCD display of E-bike
Model: KD51C.
Specifications
●Rated voltage: 24V/36V/48V
●Rated working current: 10mA
●Maximum working current: 30mA
●Off-state leakage current: <1uA
●Operating temperature: -20℃~ 60℃
●Storage temperature: -30℃~ 70℃
Appearance and Size
◆Display appearance and dimensional drawing (unit: mm)

2
◆Remote appearance and dimensional drawing (unit: mm)

3
Function summary and layout
◆Function summary
KD51C has many functions to meet the riders’ needs. The indicating elements are as
follows:
●Smart battery indication
●Assist level
●Speed indication (incl. Current speed, max. speed and avg. speed)
●ODO and trip
●The push-assistance function
●Trip time
●The lighting On/Off
●Error code indication
●Motor power
●Range
●Various parameters settings (e.g., wheel size, speed-limited, battery level bar, Assist
level, controller limited current, max speed, password enable, etc.)
●Recover default settings
◆Function Layout
Functional Area Distribution

4
General Operation
◆Switching the E-bike System On/Off
To switch on the E-bike system and provide the power supply to the controller, hold the
On/Off button on the remote for 1 second.
To switch off the E-bike system, hold the On/Off button for 2s. The E-bike system no
longer uses the battery power.
When E-bike system is switched off, the leakage current is less than 1 μA.
■When the E-bike is parked for approx. 10 minutes, the E-bike system switches off
automatically.
◆Display Interface
After switching on the E-bike system, the display will show Current Speed and TRIP by
default.
Press “i” button on the remote to switch between the indication functions below:
Trip Distance (Km)→ODO (Km)→Trip Time (min)→Max. Speed (Km/h) → Avg. Speed
(Km/h) → RANGE (Km)
Display interface
◆Switching Push-assistance Mode On/Off
To activate the push-assistance function, press and hold the “-” button on the remote.
After 2 seconds, the E-bike is activated to go at a uniform speed of 6 Km/h while the screen
shows ‘ ’.
The push-assistance function is switched off as soon as you release the “-” button .

5
Push-assistance Mode
▉Push-assistance function may only be used when pushing the E-bike. Be aware of
danger of injury when the wheels of the E-bike do not have ground contact while
using the push-assistance function.
◆Switching the Lighting On/Off
To switch on E-bike front light or rear light, briefly press the “ ” button on the remote.
The display backlight brightness is automatically reduced while the screen displays .
Likewise, briefly press the “ ” button again, the bike front light or rear light can be switched
off and display backlight recover its brightness.
*If E-bike front light or rear light is independent of “ ” button, the “ ” button can only
be used to switch on/off the display backlight.
Switch the Lighting On/Off Interface
◆Assist Level Options
The assist level of the E-bike drive can be changed anytime, even during riding.
The assist level ranges from 0 to 5 (level 0 to level 5). The default assist level is “1” when
the display is started. The output power is zero on Level “0”. Level “1” is the minimum output
power. Level “5” is the maximum output power.
Press +/- button on the remote to switch between the E-bike system assist levels and
change the motor output power.

6
Assist Level “5”
◆Battery Indicator
The five battery bars represent the capacity of the battery. Each bar is equivalent to a
capacity of approx. 20%. The five battery bars are bright when the battery is in full voltage.
When the battery is in low voltage, battery frame will flash to give a notice that the battery
needs to be recharged immediately.
Flash in low voltage
Battery Indicator
◆Motor Power Indicator
The power of the motor can be read via below interface.
Motor Power Indication

7
◆Error Code Indication
The components of the E-bike system are continuously and automatically monitored.
When an error is detected, the respective error code is indicated in text indication area.
Refer to the detail message of the error codes in Attached list 1.
Error Code Indication
▉Have the display inspected and repaired when an error code appears. Or else, you
will not be able to ride the bike normally. Please always refer to an authorized bicycle
dealer.
General Settings
To access General Settings menu, hold both the “+” button and the “-” button for 2s.
▉All the Settings are completed on a parked E-bike.
◆Trip Distance Clearance
TC represents trip distance clearance setting. The default is N.
To clear trip distance, press the “+” button or the “-” button until the Y is displayed.
To store a changed setting, press the “i” button and then access backlight settings
Trip Distance Clearance Settings Interface

8
◆Backlight Settings
bL represents backlight settings. Level “1” is the low brightness, Level “2” is the
medium brightness, and Level “3” is high brightness. The default level is “1”.
To modify the backlight brightness, press the “+” button or the “-” button to choose the
desired setting item.
To store a changed setting, press the “i” button and then access the unit toggling
Settings.
Backlight Brightness Settings Interface
◆Unit km/mi toggling
Urepresents unit settings, “1” is mile and “2” is kilometer. The default value is “2”.
To toggle unit, press the “+” button or the “-” button to choose the desired setting item,
and then press the “i” button to confirm.
To store a changed setting, press the “i” button and then access trip distance clearance
settings again or hold the “i” button for 2s and exit General Settings.
Mile and Kilometer toggling Settings Interface

9
General Parameter Settings
To access General Parameter Settings interface, hold both the “+” and the “-” button
for 2s (General Settings page) and then hold both “-” button and remote “i” button for 2s
again.
◆Wheel Diameter Settings
Ld represents wheel diameter settings. Optional values are 16, 18, 20, 22, 24, 26, 700C
and 28. The default value is 700C.
To change basic settings, press the “+” or the “-” button to increase or decrease until the
desired value is displayed.
To store a changed setting, press “i” button and then access the speed-limit settings
interface.
Wheel Diameter Settings Interface
◆Speed-limit Settings
LS represents the limited speed settings. When the current speed is faster than speed
limit, the E-bike system will switch off automatically. Speed limit range is 12Km/h to 40Km/h.
The default value is 25Km/h.
To change basic settings, press the “+” or the “-” button to increase or decrease until the
desired value is displayed.
To store a changed setting and exit General Parameter Settings, hold the “i” button for
2s.
Speed Limit Settings Interface

10
Personalized Parameter Settings
Personalized Parameter Settings can meet a variety of individual requirements. Key-
Disp displays work with different protocols, support the settings of different personalized
items. There are 8 settings items: Battery Power Bar Settings, Assist Level Settings,
Controller Over-current Cut Settings, Power Assist Sensor Settings, Speed Sensor Settings,
Throttle Function Settings, System Settings and Power-on Password Settings.
To access Personalized Parameter Settings page, hold both the “+” and the “-” button
for 2s ( General Settings page) and hold both the “+” and the “-” button for 2s again.
To access the corresponding setting page, press the “+” or the “-” button until the
desired item is displayed, and then press “i” button on remote to confirm.
Setting Item Cycle Interface
◆Battery Power Bar Settings
VOL represents voltage settings. Each bar represents a voltage value. 5 bars voltage
values must be entered one by one. For example, VOL 1 is first bar voltage value. The
default value is 31.5V. Press the “+” or the “-” button to increase or decrease the number.
To store a changed setting and access the second bar, press “i” button.
After 5 bars voltage values are entered completely, hold the “i” button for 2s to confirm
and return to the previous menu.
Battery Power Bar Settings

11
◆Assist Level Settings(optional )
‘SCA’ represents power assist level settings.
Assist level Mode Selection
In Assist level settings, there are 8 modes ：0-3, 1-3, 0-5, 1-5, 0-7, 1-7, 0-9, 1-9. The
default mode is 0-5.
To change the mode of Assist level, press the “+” or the “-” button to choose the desired
mode and press the “i” button for 2s to confirm and then access the assist level ratio settings
automatically.
Assist Level Mode Settings Interface
Assist Level Ratio Settings
The speed of each level can be adjusted to meet different riders’ needs by setting the
ratios
For example, the default ratio is 50% for level “1”; the ratio range is “45-55 percent” for
level “1”.
To change the ratio of a certain assist level, press the "+" button or "-" button to choose
the desired value, and press the "i" button to confirm and then move to the next level ratio
settings.
After ratios of all levels are set, hold the “i” button for 2s to confirm and then return to
previous menu. For ratio default values, please refer to Attached list 2.
Assist Level Ratio Settings

12
◆Controller Over-current Cut Settings (optional)
CUR represents controller over-current cut settings. CUR value can be changed from
7.0A to 25.0A. The default value is 15A.
To change basic settings, press the “+” or the “-” button to increase or decrease the
value of the current.
To store a changed setting, hold the “i” button for 2s and return to previous menu.
Current Settings Interface
◆Power Assist Sensor Settings(optional)
PAS represents power assist sensor settings.
The PAS Direction Settings
“run-F” means forward direction, while “run-b” means back direction. The default value is
“run-F”.
To change the direction of power assist sensor, press the “+” or the “-” button to select F
or b.
To store a changed setting, press “i” button and then access PAS sensitivity settings.
PAS Direction Settings
PAS direction setting interface

13
The PAS Sensitivity Settings
SCN represents the sensitivity of PAS settings. The sensitivity value is “2” to “9”. “2” is
the strongest, “9” is the weakest. The default value is “2”.
To change the sensitivity of PAS, press “+” or “-” button to choose sensitivity value.
To store a changed setting, press the “i” button and then access magnet quantity
settings mode.
PAS Sensitivity Settings
Magnet Quantity Settings
nrepresents the numbers of magnets on PAS disk. The default number is 6.
To change the number of magnets on PAS disk, press “+” or “-” button to choose the
desired quantity.
To store a changed setting, hold the “i” button for 2s and then return to previous menu.
PAS Magnet Setting

14
◆Speed Sensor (optional)
SPS represents speed sensor settings. The default value is 1
To change speed sensor settings, press the “+” or the “-” button to select the quantity of
magnet head (the range is from 1 to 15).
To store a changed setting, hold the “i” button and then return to previous menu.
Speed Sensor Setting
◆Throttle Settings (optional)
Throttle Push-Assistance Enable/Disable
HL represents throttle push-assistance function settings. HL-N represents throttle push-
assistance function is disabled. HL-y represents throttle push-assistance function is enabled.
The default value is N.
To enable throttle push-assistance function, select Y and hold ibutton for 2s to confirm
and return to previous menu.
To disable throttle push-assistance function, select N and access Throttle Level
Enable/Disable Setting below.
Throttle Push-assistance Enable/Disable Interface
Throttle Level Enable/Disable
HF-y means throttle speed is limited by current assist level while HF-n means throttle
speed is not limited by current assist level. The default value is n.

15
If you choose y, the maximum speed can only be the highest speed powered by current
assist level when you twist the throttle.
If you choose n, the maximum speed is not limited by current assist level and you can
override whatever level you are in and reach rated maximum speed when you twist the
throttle.
Press +/- to set Y or N and press “i” button to confirm and return to throttle push
assistance enable/disable setting interface or hold down the ‘i’ button for 2s to return to
previous menu interface.
Throttle Level Enable/Disable Setting
◆System Settings (optional)
Delay Time Settings for Battery Power
dLy represents battery power delay time settings. The default value is 3s.
To change delay time settings, press the “+” or the “-” button to select delay time 3s, 6s, 12s.
To store a changed setting, press the “i” button and then access the max speed limited.
Interface of Battery Power Delay Time Setting

16
Max. Speed Limit
LS represents max. speed limit settings. The default value is 40Km/h.
To change Max speed limit setting, press the “+” or the “-” button to set the max speed from
25Km/h to 40 Km/h.
To store a changed setting, press the “i” button and then access push-assistance button
enable/disable settings.
Interface of Max Speed Limit
▉The maximum speed upper limit is set by display manufacturer.
Push-assistance Button Enable/Disable
PUS represents push-assistance button settings. Y represents push-assistance button is
enabled, N represents push-assistance button is disabled. The default value is Y.
To change push-assistance button settings, press the “+” or the “-” button to choose Y or N.
To store a changed setting, press the “i” button to confirm and access Slow Start Up settings.
Push-assistance button Enable/Disable Settings

17
Slow Start up Settings
SSP represents slowly start up. The range is “1-4”, “4” is the slowest. The default value is “1”.
To change slowly start up settings, press the “+” or the “-” button to select the desired
value.
To store a changed setting, press the “i” button and return to Delay time settings for
battery power or hold the “i” button for 2s to return to previous menu.
Slow start up settings interface
◆Power-on Password Settings
PSd represents power-on password settings. Power-on password is a 4-digit code. The
default password is “1212”.
Press i button to enter the interface where “P2, 0000” is shown on the screen. Please
input the current password or default password’1212’.
Press i button to increase or decrease the number and press i button to confirm digits
one by one until the correct 4-digit password is completed. Press i button to access power-on
password Enable/Disable Settings.
Otherwise stay in password input state.
Power-on Password Input Interface