How can I bypass an OEM LCD panel?

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ebike11

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Hi guys
My friend and I are trying to get his ebike up and running. The motor is a hub motor with built-in controller. The wires from the motor run from the rear to the front handle bars. The OEM LCD that in on the handlebars seems to be damaged. There are wires going to that LCD panel which shows the basic info (speed, odometer, battery indicator, etc)
There are seperate wires going to a small set of buttons on the handlebar as well that are not attached to the LCD display that turn on the bike and also +and- buttons

Since the LCD panel is damaged and does not turn on, is there a way to bypass it to get power? The battery is fully charged but the power button does not power the bike on.

Any advice is greatly appreciated thanks!!! :D

A little update..I seen these wires going into the LCD panel. When I removed the back cover I seen : "TX" grey wire, "RX" white wire, "B+" pink wire, " K " yellow wire and "GND" black wire on the pcb

Would any know what the TX, RX, and K stand for?
 
Transmit data, receive data and probably key. The B+ wire carries battery voltage to the lcd. When you switch it on, it sends the voltage back down the K wire to power the controller. You can therefore try joining those two wires. Without the tx and rx to communicate with the lcd, you might get the lowest power setting or no power at all. If it doesn't work like that, you could also try joining tx and rx plus the B+ and K.

Which bike is it? Show a picture of the lcd. Some bikes use CANbus communication. If yours foes, I doubt that you'll be able to make it work.
 
Success thanks to d8veh!
I bypassed the lcd panel..connected the K and B+ together but nothing..then connected the RX and TX wires together and the bike runs but since the lcd is bypassed I think the motor is stuck on Level 1 mode. There are 5 speed modes.
A couple of questions..

1. Would it be possible to buy a generic LCD from an online vendor and match up the wires to it in order to increase the speed level?

2. If not...would a momentary switch between the RX and TX allow me to increase the speed level? ( may sound dumb, the idea just popped up in my head haha)

Thanks once again!
 
Ypedal said:
you need to show exactly what you have, otherwise .. well... brand, model, pictures.. something.
Click to expand...

Well the bike components are not a well known brand..made in china I believe but the bike was bought in korea
The maker of these bikes only sell domestically so there isnt much info at all that I can find on them :cry:
 
Ok..Ill get my friend to take some pics of it. The bike is running now..just trying to figure out if a generic LCD with the same wires will be able to increase the speed level...if we can get it to 3 to 5 then it will be sufficient
 
flangefrog said:
You won't want to join the RX and TX together. This will just send anything the controller is trying to send to the display back to itself.
Click to expand...

But its the only way that the motor will run. When I connected just the B+ and K wires together the motor didnt turn. But after connecting the RX and TX then the motor turned. There are 5 wires total going to the LCD. The other wire is GND(black)
 
Edit: This answer is about the using the throttle without the LCD. It is less suitable for the PAS.
You have to compensate by soldering some length of the current shunt, otherwise the controller is current limited. There is a software limit inside when the LCD is missing.
shuntmod.jpg

This picture is stolen from the http://neptronix.org/forumpics/shuntmod.jpg

Do it several times, 3mm at the time. Check the motor temperature before you solder some more. Be sure to reset the shunt before attaching the LCD again, otherwise bad things can happen (to much of power=burned motor).

The other (wiser) solution is to connect a miniature 15~30A fuse inside a fuse holder to act as a jumper. You have to find the point on the shunt that corresponds to the normal operation.
No fuse=LCD display mode.
Fuse inserted=No LCD attached mode.
 
Soldering the shunt won't work if your controller uses speed control (normal), although that sounds like a solution for KT controllers that use current control.

If you show us what ou have, we can probaly show you where to get a compatible LCD, which would be the best solution.

Controllers are cheap compared with LCDs. Normally, it's bet to buy them as a pair. You might want to think about replacing your interal contoller with an external one, which can offer a lot of advantages.
 
Would putting a momentary switch between the RX and TX wire be able to increase the speed increments?
 
ebike11 said:
Would putting a momentary switch between the RX and TX wire be able to increase the speed increments?
Click to expand...
No.

Both the controller and LCD are talking to each other like you and me talking on the phone. If I'm not there, it doesn't matter how you connect the phone lines, you still won't be able to hear me.
 
d8veh said:
ebike11 said:
Would putting a momentary switch between the RX and TX wire be able to increase the speed increments?
Click to expand...
No.

Both the controller and LCD are talking to each other like you and me talking on the phone. If I'm not there, it doesn't matter how you connect the phone lines, you still won't be able to hear me.
Click to expand...

Ok got it thx...i guess ill have to perhaps replace the lcd panel
 
Do you think buying a generic lcd like this to match my 36v battery and controller could work?

http://m.aliexpress.com/item-desc/32406089775.html

Perhaps by splicing the correct wires to the existing 5 wires that are at my handlebars coming from the motor/controller?
The 5 wires are the GNG, K, B+, TX, RX
 
d8veh said:
There's a chance it might work. Why don't you show a photo of your present one?
Click to expand...
Ok..ill get one up when i get back home. My lcd is almost in pieces though now coz i had to get to the back side and remove the back cover
 
http://www.bigstone-nj.com/products/lcd-display/c600e

This lcd seems to be the exact same as was on the bike
 
Any Bigstone one will work. You can find them on Aliexpress. Get one of the correct voltage.

http://m.aliexpress.com/item/362901134.html
 
d8veh said:
Any Bigstone one will work. You can find them on Aliexpress. Get one of the correct voltage.

http://m.aliexpress.com/item/362901134.html
Click to expand...

Ok thanks...do you think all of the Bigstone panels have the same circuitry?
Because the ones on aliexpress are from Bigstone but different lcd shape and design
 
http://m.aliexpress.com/item/362901134.html
This link looks all buggered up to me.

http://www.aliexpress.com/item/E-bicycle-LCD-display-36V-24V-48V-Conversion-Kits-CE-approved/362901134.html
Looks better as I see it.
 
A little update..my friend and I bought a bigstone LCD

http://m.aliexpress.com/item/697870440.html


The 5 wires from the original bikes controller to handlebars are 
positive
negative
yellow key on wire
gray TX wire
white RX wire

But on the new LCD the 5 wires are
positive
negative
blue key on wire (which I connected to the yellow wire above)
green speed sensor signal wire
* I copied this info from the manual: white wire (Controller voltage A/D signal sampling mouth (Note: A/D signal sampling mouth of controller, its inside circuit can't have pull or down resistance)

So I have 2 wires on the lcd to connect and 2 wires coming from the controller.
I was afraid to burn out something so thought Id ask first before connecting wires at random

Thanks!
 
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