Key-Disp KD78C User manual

Contents
Product name and model.............................................................................................................................................................1
Specifications................................................................................................................................................................................1
Appearance and dimension..........................................................................................................................................................1
Function and button definition.................................................................................................................................................... 2
◆Function summary................................................................................................................................................................... 2
◆Button definition......................................................................................................................................................................2
General operations...................................................................................................................................................................... 3
◆Switch the E-bike system ON/OFF..................................................................................................................................................3
◆Display interface.......................................................................................................................................................................3
◆Switch push-assistance mode ON/OFF....................................................................................................................................3
◆Switch lighting ON/OFF............................................................................................................................................................4
◆Assist level selection................................................................................................................................................................4
◆Battery level indicator.....................................................................................................................................................................4
◆Error code indication..............................................................................................................................................................5
General Settings..........................................................................................................................................................................6
◆Trip distance clearance...........................................................................................................................................................6
◆Backlight brightness................................................................................................................................................................6
◆Toggle the unit KM/miles........................................................................................................................................................7
◆Wheel diameter....................................................................................................................................................................7
◆Speed limit............................................................................................................................................................................7
Personalized parameters settings................................................................................................................................................ 8
◆Battery power bar settings...................................................................................................................................................8
◆Assist level settings...............................................................................................................................................................9
Assist level mode.................................................................................................................................................... 9
Assist level ratio settings....................................................................................................................................................9
◆Current limit settings..................................................................................................................................... 9
◆Power assist sensor settings...............................................................................................................................10
PAS direction settings........................................................................................................................................................ 10
PAS sensitivity settings.......................................................................................................................................................10
PAS magnet quantity settings............................................................................................................................................11
◆Speed sensor settings........................................................................................................................................11
◆Throttle function settings...................................................................................................................................11
Throttle- 6km enable/disable settings...............................................................................................................................12
Throttle-PAS enable/disable settings................................................................................................................................ 12
◆System setting.............................................................................................................................................13
Battery power delay time settings.....................................................................................................................................13
Button- 6km enable/disable settings.................................................................................................................................13
Slow start up settings.........................................................................................................................................................13
◆Power-on password settings.............................................................................................................................................. 14
Power-on password Enable/Disable..................................................................................................................................14
Power-on password change...............................................................................................................................................15
◆Exit settings.........................................................................................................................................................................15
Factory settings.............................................................................................................................................................15
Appendix 1：Personalized settings symbols........................................................................................................................16
Appendix 2：Other symbols definition......................................................................................................................................17
Quality assurance and warranty scope...................................................................................................................................... 18

Warnings.....................................................................................................................................................................................18

1
Product name and model
E-bike Intelligent LCD display
Model: KD78C
Specifications
●2.0” segment LCD
●24V/36V/48V/52V Power Supply
●Rated working current: 10mA
●The maximum working current: 30mA
●Communication: Uart/CAN
●Operating temperature: -10℃~ 40℃
●Storage temperature: -20℃~ 60℃
Appearance and dimension
Display picture and dimensional info (unit: mm)

2
Function and button definition
◆Function summary
KD78C display has many functions to meet riders’ cycling needs. The indication elements are as
follows:
●Intelligent Battery SOC
●Motor power indicator
●Assist level indicator and adjustments
●Speed indication (incl. current speed, Max. speed and Avg. speed)
●ODO and Trip
●Push-assistance control and indicator
●Trip time
●Backlight on/off and headlight indicator
●Light sensor
●Error code indication
●Various parameter settings (e.g. settings for backlight, Unit, Battery voltage segmented values, PAS level
settings, Password etc.)
●Recover default settings
●Bluetooth function (optional)
KD78C Function layout interface
◆Button definition
KD78C button model is K41 with 4 keys: ON/OFF button, i button, +/light, -/push-assist

3
General operations:
◆Switching the E-bike System On/Off
When battery power is on, the display switches on automatically. when battery power goes out, the display
switches off automatically.
When E-bike system is switched off, display does not use the battery power any more. the leakage current is
less than 1 μA.
■When the E-bike is not in use for 5mins, the E-bike system switches off automatically.
◆Display Interface
After switching on the E-bike system, the display shows current Speed and Trip by default.
Press remote “i” button to switch between indication elements below:
Trip Distance (Km)→ ODO (Km)→ Trip Time (Min.)→ Power (Watts)→Max speed (km/h)→Avg speed
(km/h).
Display indication cycle interface
◆Switching Push-assist Mode On/Off
To activate the push-assist function, press and hold the “-” button. After 2 seconds,
E-bike is activated to go at a uniform speed of less than 6 Km/h while the screen displays . .
When “-” button is released, the e-bike will immediately stop power output and return to the state before
push-assist is engaged.
Push-assistance mode

4
◆Switching Lighting On/Off
Hold +for 2 seconds, display backlight dims and bike headlight is on and headlight icon comes out. Hold +
button for 2 seconds again to switch off the headlight and light icon is gone and display backlight brightness
recovers.
Headlight-on Interface
◆Assist Level Selection
Press "+" or "-" button to switch between the E-bike system assist levels and change the motor output
power. The default assist level mode is 0-5( level “0” to level “5”). The output power is zero on Level “0”.
Level “1” is the minimum output power. The default assist level is level “1”.
Assist level interface
◆Battery level Indicator
The five battery bars represent the capacity of the battery. Five bars are bright when the battery is in full
voltage. When the battery is in low voltage, battery frame will flash at the frequency of 1HZ to give a notice that
the battery needs to be recharged immediately.
Battery level indicator interface
Flash (low voltage)

5
◆Motor Power Indicator
The watts value of the motor can be read via interface below by digits.
Motor power interface
◆Error code indication
The components of the E-bike system are continuously and automatically monitored.
When an error is detected, the error code comes out and malfunction icon shows. The whole interface is
code plus error indication icon.
Error code interface
■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.

6
General Settings
At the normal display interface, hold both ‘+’ and ‘-’ simultaneously for 2 seconds to enter General Settings.
▉All the Settings are done to a parked E-bike. Please refer to attached list 2 for the symbol definition.
◆Trip Distance Clearance
TC represents trip distance clearance setting.
To clear trip distance, press “+” button or “-” button to select Yes or No. Yes represents clearing a trip
distance. No represents not clearing a single ride distance.
To store a changed setting, press the “i” button and then access Backlight Brightness Settings.
Trip distance clearance interface
◆Backlight settings:
bL represents backlight settings. Level “1” is the lowest brightness. Level “2” is the standard brightness. Level
“3” is the highest brightness. The default value is “1”.
To change the backlight brightness, press the +/- button to increase or decrease until the desired brightness
level is displayed.
Press ibutton to store a changed setting and then access unit toggling settings.
Backlight settings interface

7
◆Toggle the unit KM/Mile
Urepresents unit settings, “1” is mile and “2” is kilometer. The default value is “2”.
To toggle the unit, press the +/- button to switch between KM/Mile for the speed and mileage.
Press the ibutton to store a changed setting and then access trip distance clearance setting again
or hold the ibutton for 2s and exit General Settings.
Miles and KM toggling interface.
★At General Settings page, hold i button ad - button for over 2 seconds to enter the wheel set and
speed limit set.
◆Wheel size set
Ld means wheel size，settable values are：16”,17”,18”,19”,20”,21”, 22”,23”,24”,25”,26”,700C，28”。Press+/-
to choose the desired wheel size to correctly show the speed and mileage on the display. Press i button to store a
changed set and access to the next set interface.
Wheel size interface
◆speed limit set
LS means top speed limit and the settable range is 12 km/h to 40km/h. press +/- to set the values and
press i button to confirm the setting.
Speed limit interface

8
Personalized Parameter Settings
Personalized Parameter Settings can meet a variety of requirements. 8 settings are Battery Power Bar
Settings, Power Assist Level Settings, Over-current Cut Settings, Power Assist Sensor Settings, Speed Sensor
Settings, Throttle Function Settings, System Settings and Power-on Password Settings. Refer to appendix 1 for
the symbol meanings.
Hold +and -button simultaneously for 2 seconds to enter General Settings and Hold +and -button
simultaneously for another 2 seconds to enter personalized parameter settings interface.
Press +or -button to choose the desired personalized parameter setting item, then press ibutton to enter the
setting interface.
Personalized setting item cycle interface
◆Battery Bar Settings
VOL represents voltage settings. Each bar of the battery pack symbol represents a voltage value. Each of the
5 values (31.5V-34.5V-35.6V-37.4V-39.2V ) is to be entered one by one. For example, VOL 1 is the first battery
bar and its default value is 31.5V. Press +or -to increase or decrease the voltage value. Press ibutton to store a
changed setting and access the second battery bar setting. Likewise you can set the values in the same manner
for other bars. After desired values for 5 bars are entered completely, hold i button for 2 s to confirm and return to
previous menu.
Battery bar settings interface

9
◆Assist Level Settings
Assist level mode options
SCA represents assist level settings. The default assist mode is 0-5. Press i button to enter the assist level
ratio settings
Assist level interface
Assist level ratio settings
The speed of each assist level can be adjusted to meet different riders’ needs by setting the ratios.
For example, the default ratio is 50% for level “1” and the ratio range is 45%-55% for level ”1”.
To change the ratio of a certain power assist level, press the +/- button to choose the desired
percentage, and then press the "i" button to confirm.
To store a changed ratio, press the “i” button to confirm and move to the next level ratio setting.
After ratios of all levels were input, hold the “i” button for 2s to confirm and return to previous menu.
Assist level ratio settings interface
◆current limit settings
CUR represents controller over-current cut settings. The current value ranges from 7.0A to 22.0A. The default
value is 15A.
To change a current value, Press the +/- button to increase or decrease to choose the desired value.
To store a changed setting, hold ibutton for 2s to confirm and return to previous menu.

10
Current settings interface
◆Power assist sensor settings
PAS represents power assist sensor settings.
PAS direction settings
“run-F” means “go forward” while “run-b” means “go backward”. The default value is “run-F”.
Press the +/- button to select F or b to change the direction of Power Assist Sensor.
To store a changed setting, press ibutton to confirm and access PAS sensitivity settings
PAS direction settings
PAS Sensitivity Settings
SCN represents PAS sensitivity settings. The sensitivity value ranges from “2” to “9”. “2” is the strongest, “9” is
the weakest. The default value is “2”.
To change the PAS sensitivity, press the +/- button to choose the desired sensitivity value.
To store a changed setting, press ibutton to confirm and access magnet disk settings.
PAS sensitivity settings

11
PAS Magnet Quantity Settings
nrepresents the quantity of magnets in PAS. The default value is 6.
To change the number of magnets in PAS, press the +/- button to choose the desired quantity
To store a changed setting, hold ibutton for 2s to confirm and return to previous menu.
PAS magnet quantity settings
◆Speed sensor settings
SPS represents speed sensor settings.
Press the +/- button to choose the quantity of spoke magnets (the range is from 1 to 15).The default value is 1
To store a changed setting, hold ibutton for 2s to confirm and return to previous menu.
Speed sensor magnet settings
◆Throttle function settings
Throttle -6km enable/disable
HL represents throttle push-assistance function settings. HL-N means throttle push-assistance function is
disabled. HL-y means 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

12
Throttle push-assistance enable/disable
Throttle-PAS 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.
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 ibutton 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

13
◆System settings
Delay time settings for battery power
DLY represents battery power delay time settings.
Press the +/- button to choose delay time 3s, 6s, 12s to change the settings.
Delay time settings for battery power
◆Push-assist enable set
PUS means push-assist enable set. Press +/- to choose Y or N. Y is enabled while N is disabled. Press i
button to confirm and enter the push-assist speed set. The default value is Y.
Push assist enable setting
◆SSP
SSP means slowly start up, range is 1~4. 4 is the slowest. Press +/- to choose your desired values. Hold i
button to confirm and exit the settings

14
Slowly start up interface
◆Password settings
Press i button to enter the password set. P2 is shown on the screen. Press +/- to increase or decrease the
values and press i to move to the next digit. After 4 digits were entered, press i to confirm. If password is correct,
then enter to the password enable set interface. Or else, it keeps in password input state.
password input and set interface
Password enable
Press +/- to choose Y or N. Y means password is needed while N means password is not needed. Press i
button to confirm. If Y is chosen, press i button to enter password change state. Or else, it will exit password set
interface and return to the display setting items interface.

15
Password enable interface
Password change
Display shows P3 and press +/- to increase or decrease the values and press i button to move next digit.
When password is changed, long press i button to confirm and store the new password and display exits from set
interface. When display is restarted, P1 0000 shows. Enter the new password correctly to get the display working
normally.
Password change
◆Exit the settings
In settings interface,
Press i button to confirm and store the current settings.
Hold i button to confirm and store the settings and exit from current settings.
■If there is no operations in one minute, the display will exit settings interface automatically.
◆Factory settings
dEF means factory settings, at home screen, hold + and i button simultaneously for more than 2 seconds to
do factory settings. Press +/- to switch between Y and N. If Y is chosen, hold i button for more than 2 seconds and
display will be reset to factory settings and shows dEF-0 on the screen. It returns back to home normal screen
when the factory setting is done.

16
Factory settings interface
Appendix 1：personalized setting symbols
Serial
Setting items
Symbols
1
Battery level bar set
2
PAS parameters set
3
Current limit set
4
Pas sensor set
5
Speed sensor set
6
Throttle set
7
System set
8
Start-up password

17
Appendix 2：other symbols definition
Serial
Symbols
Definition
1
Trip distance clearance
2
Light sensor
2
Backlight
3
Unit
4
Voltage
5
Wheel
6
Speed limit
7
Current limit
8
Backward
9
Forward
10
PAS sensitivity
11
Speed sensor
12
Battery delay timing
13
Throttle -6km
14
Throttle -PAS
15
Push-assistance
16
Slow start up
17
Password
18
Reset to defaults
19
yes
20
no