A wiring mess I need to figure...

[bluesoleli]

Hi Everyone,

Just helping re-wire a "Longwise" electric bike for a friend of mine. I don't exactly know what he's done but he has cut a bunch of wires and handed it over and asked me to fix it. Doesn't help me at all with these cut cables. He said the controller was dead so he didn't know how to get the LCD display cables and the motor cables out of the frame so he cut them...

He has however, provided me with a new LCD display and a new motor wheel as well, from an identical bike but step through (The one I am fixing is an MTB). I checked the motor wheel and the controller and they do indeed match the ones on the bikes now.... says 120 degree angle and 36V from Longwise.

What I want to do first is to get power to the LCD display... like get it to turn on. No need to connect the motor wheel yet, just to get the LCD to turn on. However, the problem lies in the wiring... I don't know which wire goes where without a diagram, let alone what each one does as the colours don't match up! Manufacturer logic much.

Does anyone know which each wire does in the following photos and what I need to do just to bring the LCD display to life? (Just the LCD for now)

Have checked the battery and it is alive with 36V on my multimeter. So far I have worked out motor phase and the other 5 pin motor cable. That's about it. The rest is a jungle to me. I have built many e-bikes in the past but at least they were colour coded correctly!

Anyway, photos below.

controller end

lcd end

lcd display

 

[bluesoleli]

Anyone...?

 

[dnmun]

match the colors of the wires he cut and solder them back together. then you can diagnose what is wrong with it.

 

[mlt34]

Here are my thoughts. White labels are for sure, yellow is what I think.

The e-brake or light wires can be determined by checking for voltage drop if you apply power to the controller. If you see 36V there, they are light wires. If I had to guess, the grey/black is ebrakes and the orange black is lights.

The LCD wires I'm a little less sure of. It's likely that the red wire in the upper connector is your positive lead and the black wire in the bottom connector is your negative. You can check these for voltage drop when you power on the controller. Those could power up your controller.

Many controllers that require LED displays can be 'turned on' without the display by shorting two of the display wires from the controller, perhaps the red/orange in this case. That's a guess though since I don't experience with this exact controller, just many others with varying degrees of similarity…

Good luck and us know what you find!

 

[mlt34]

Oh and as for the LCD display end, many displays don't use all their wires. Lots of bikes come with a couple connectors left. The displays are usually manufactured separately from the controllers and may have extra functions not supported by the controller, which is why you likely won't use all four of those plugs. That single blue one, for example, is likely data for turning on a light, starting/stopping cruise control, or any number of other things...

 

[d8veh]

Did that controller work the same LCD before, or is the LCD an addition? Did you change the controller for a different type because those connections don't look typical of those that go with a LCD? There's normally a single 5-pin connector like your hall sensor one. If your controller is a sensorless one, then that five-pin connector is not for halls. It's for the LCD. When the battery is connected, check the voltage between the black and the red. If it's 5v, that's for halls, if it's battery voltage, it's for the LCD.

To get the controller to work with the throttle for testing, you don't need the LCD. You only have to bridge the yellow and orange wires on the white connector.

The LCD has five wires:
36v/48v supply from battery (normally red). Connects to the thin red next to the orange.
Ground (black). Connects to any black.
36v/48v bavk to the controller. (can be any colour, maybe blue). Connects to the orange next to the red.
TX (can be any colour)
RX (can be any colour)

Additionally, there may be a two wire connector for lights (black ground and yellow for 36/48v)

You can test a few things. If you connect the red and black wires to the LCD, you'll be able to switch it on. When it's on, one of the other wires (blue?) will become live with 36/48v, so you know to connect it to the controller's orange. Then the controller will work with the throttle. Other information is sent via TX and RX for the PAS settings, so you might get default level 1 or anything else.

 

[mlt34]

In Israel (and by that I mean chinese bikes that come to Israel and likely go to many other places) it's pretty common for the LCD connector to be broken into two or three connectors. They do this so you can fit the connectors through a hole in the controller box mounted somewhere on the frame, usually below the battery and behind the bottom bracket.

 

[bluesoleli]

Tried everything I could using what I read above. no go.

Sent it to an electrical engineer friend.

He came back telling me the controller was toast. He assumes someones plugged a higher voltage in or whatever and fried it. This is the "new" controller as well... one removed from another bike.

Going to send it back to the client and tell them to buy a new bike esp. after mr. smart cut all the wires thinking he knew what he was doing.