Need help bafang hub 48v500w kt-lcd8

Hello
I need help to programming my controller bike.
I use a Fatbike 26x4.0 with a rear hub bafang 48v500wand a 10.4ah battery.
I use a controller KT 48v14A and and other 48v22A with a lcd kt-lcd8.
I can use my throttle and my pas.

I have 2issues:
-When the battery loose power (less 50%) and when I want to use too much power like pas 5 or throttle, the motor shut down.
-Other issue, the monitoring speed is not correct. start to display few second after start engin and when I do not use pas down to 0kmh.

My controller setting is:
P1 = 100 (Motor Characteristic Parameter Setting Mode, 1 - 255)
P2 = 1 (Wheel Speed Pulse Signal Setting Mode, 0 - 6)
P3 = 1 (Power Assist Control Mode, 0 or 1)
P4 = 0 (Handlebar Startup Mode, 0 or 1)
P5 = 15 (Power Monitoring Mode, 0 - 40)

C1 = 5 (Power Assist Sensor and Parameter Select Mode, 00 - 07)
C2 = 0 (Motor Phase Classification Coding Mode, 0 - 7, 0:sin wave)
C3 = 1 (Power Assist Ratio Gear Initialization Mode, 0 - 8 ) (C3=6 WARNING! Bike starts running forward on it’s own at power up!)
C4 = 3 (Handlebar Function Setting Mode, 0 - 4)
C5 = 4(try 1 to 10) (Controller Maximum Current Adjustment Mode, 00 - 10)
C6 = 1 (Backlight Brightness Adjustment Mode, 1 - 5)
C7 = 1 (Cruise Function Setting Mode, 0 or 1)
C8 = 0 (Motor Operating Temperature Display Mode, 0 or 1)
C9 = 0 (Startup Password Setting Mode, 0 or 1)
C10 = n (Automatically Restore Default Setting Mode, n or y)
C11 = 0 (Attribute Selection Mode, 0 - 2)
C12 = 4(try 1 to 7) (Controller Minimum Voltage Adjustment Mode, 0 - 7)
C13 = 0 (Brake energy recovery - recuperation - only works with the corresponding controller, 0 - 5)
C14 = 2(try 1 to 3) (Coordination of support levels, 1 - 3, 2 = standard)


thank you

I may be able to help on the indicated speed thing. I think it needs a speed sensor. While pedaling it can look at the cadence sensor to get an idea of how fast you're going. It may even be able to measure motor rpm's while under power. But while coasting, the motor clutch is disengaged - so no speed signal to measure. Speed sensors inexpensive, easy to install, and the KT controllers I've messed with have all been set up for them.


On the motor shutting down thing, that's usually got something to do with over current or heat build up somewhere. I see you have the max amperage set way back already (C5=4), and the motor should be able to handle that, so I would be wondering about the BMS board on the battery, if it's up to the task.

That's it. In a few words, you need an external wheel magnet type speed sensor and your crappy battery can't provide the current. Do you know which cells you have in it and what max current the BMS allows?

The controller picks up the speed signal from the motor when it doesn’t have a specific speed sensor, in which case the speed only shows when the motor is driving the wheel. As soon as you freewheel, the motor and speed shown go to zero.

Thank you for your answers.
About speed sensor, it's an hall sensor. before change the controller I haven't any issue.
And after few second after start engine I can see the speed display so I thinking about a configuration issue.

About the battery issue, I thinking bms issue or controller programming....
I use the same battery a lot for now 2 years and I have no idea about information about this.
I buy a new one today with a 30A BMS

Your controller configuration is correct with P2=1. That is the setting to use a motor's internal speed sensor or an external wheel speed sensor. You can set P2=0, which will take the speed signal from the motor, but it will only show you the speed when the motor is driving the bike.

Your motor should have an internal speed sensor, which you can test by seeing 5v pulsing once per rotation on the white wire in the motor cable. You can only check that when the motor cable is connected and the bike power switched on. Sometimes the magnet in the motor detaches, so you no longer get a signal from it, in which case the quickest and easiest solution is to fit an external sensor.

A final thought: Some motors have 6 magnets for the internal sensor, and I think yours is like that, so if your LCD speed display works but gives a very low speed, you need to set P2=6.