Carrera /Raleigh Suntours LCD

[Baz the balloon man]

Hi all
We have a new member Andy who contacted me through e bay .

Andy wants to use the older 3 wire Suntour LCD screen larger one on his Raleigh Array that has the new Small LCD but this has four wires .

Can any one help ie can they be wired up to work without changing the controller and possibly PAS sensor .

As they want a larger display .

Here is his message to me and a photo of the two LCD screens and wires

Hi Baz,
Be great if you're able to sort a couple of displays for me.
I'm an electronics engineer so I'm fairly confident I can rewire anything that's needed.
Are you able to send some images of the displays so I know which ones we're talking about?
Feels like I've been banging my head against a brick wall trying to get info on the protocol used by Suntour!!!!
Many thanks,
Andy

 

[Baz the balloon man]

The controller In the photo is from a new Raleigh Array that I am swapping out to KT kit

 

[Baz the balloon man]

Here is the bike

 

[saneagle]

All LCD control panels need a minimum of 5 wires to operate:

• Ground
• Battery voltage
• Switched battery voltage to power the controller
• Tx
• Rx

Some have a 6th wire to power lights directly. The older analogue LED control panels can have 4 wires because they use a single wire with varying voltage levels to signal the controller rather than Tx and Rx.

4 wires and 3 wires are therefore not possible on the Suntour system, so you're probably missing something somewhere. If it has CANbus comms, it would work slightly differently, but you still need at least two wires for the comms.

 

[matthewslack]

If you can work out what the 3 / 4 wires are for in each case, you might be able to answer this by experimenting.

For example, one in both cases will be ground, one is likely +5V, others are comms or signals. UART comms uses separate wires for each direction of communication, so technically possible to manage with 3 wires if comms are one direction only, or if display has internal battery so does not need +5V supply.

So check colour of all wires in both cases, see if all of the three match three of the four.

Be prepared for the answer to be no, as pairing controller and display is common practice.

 

[Baz the balloon man]

Thanks guys as always very helpful . I think Andy is more qualified than I to experiment like this .

On the older Suntours screen as in the picture do you know if just a replacement PCB can be bought from Suntours ?
I sold my Giant road bike I am just to heavy for it to a doctor who works at my local hospital in Hampstead I think we will be getting another new member .

My doctor said using the bike is much better for me than walking as to the Arthritis in my knees so the bike in the picture is going to be the one I will get a legal 15MPH throttle on .

KT controller and screen HL battery and wired into the Suntours back motor for now . But I will eventually change it to mid drive and 48V as Saneagle advised .if it fits the BB.

 

[Baz the balloon man]

All LCD control panels need a minimum of 5 wires to operate:

• Ground
• Battery voltage
• Switched battery voltage to power the controller
• Tx
• Rx

Some have a 6th wire to power lights directly. The older analogue LED control panels can have 4 wires because they use a single wire with varying voltage levels to signal the controller rather than Tx and Rx.

4 wires and 3 wires are therefore not possible on the Suntour system, so you're probably missing something somewhere. If it has CANbus comms, it would work slightly differently, but you still need at least two wires for the comms.

I am a bit confused definitely only 4 wires going into controller from LCD .
The bike has lights but they have a separate connection directly into the controller .
It is the Canbus controller and battery .

I have to try fix this first though to see if it works I got the bike at auction brand new but with no battery and when I stripped it out I found the plug broken .

The controller is brand new so I am not going to mess with it as it’s on sale on e bay

 

[saneagle]

The writing on the back says SW102C. I guess the C means CANbus. Bafang uses the same display for CANbus, but it has 5 wires. The power wires for the display are separate to the comms, so any powered CAN device needs a minimum of 4 wires. The Bafang one has 5 wires because the fifth (labelled key) is the switched wire that's needed to power the controller so the controller is only on when the LCD is on. All ebikes I've ever seen have been 5 wires for that reason apart from the old analogue systems, where only one wire is needed for comms.

If the Suntour display only has 4 wires, they would be the two CANbus wires plus the two power wires, which would mean it's not switching the controller on. In that case, the controller would be on all the time the battery is on, which is unusual.

In summary, and to answer your question, the two systems cannot be compatible with each other. They have different comms and work differently.

 

[Baz the balloon man]

If you can work out what the 3 / 4 wires are for in each case, you might be able to answer this by experimenting.

For example, one in both cases will be ground, one is likely +5V, others are comms or signals. UART comms uses separate wires for each direction of communication, so technically possible to manage with 3 wires if comms are one direction only, or if display has internal battery so does not need +5V supply.

So check colour of all wires in both cases, see if all of the three match three of the four.

Be prepared for the answer to be no, as pairing controller and display is common practice.

So if we have one 4 wires and one 3 wire I would think match 3 col

The writing on the back says SW102C. I guess the C means CANbus. Bafang uses the same display for CANbus, but it has 5 wires. The power wires for the display are separate to the comms, so any powered CAN device needs a minimum of 4 wires. The Bafang one has 5 wires because the fifth (labelled key) is the switched wire that's needed to power the controller so the controller is only on when the LCD is on. All ebikes I've ever seen have been 5 wires for that reason apart from the old analogue systems, where only one wire is needed for comms.

If the Suntour display only has 4 wires, they would be the two CANbus wires plus the two power wires, which would mean it's not switching the controller on. In that case, the controller would be on all the time the battery is on, which is unusual.

In summary, and to answer your question, the two systems cannot be compatible with each other. They have different comms and work differently.

Thanks so when I get asked which is a lot I can just say if the plugs and wires match on Suntours LCD screens then the part will work . IE the 3 pin Julet orange plug works on Two of the older set ups .

The later small LCD only works on the 2023 onwards Carreras not sure about the other brands just yet. Ie `Raleigh .

I have a lot of people now asking advise I suggest they join us on here

 

[saneagle]

So if we have one 4 wires and one 3 wire I would think match 3 col

Thanks so when I get asked which is a lot I can just say if the plugs and wires match on Suntours LCD screens then the part will work . IE the 3 pin Julet orange plug works on Two of the older set ups .

The later small LCD only works on the 2023 onwards Carreras not sure about the other brands just yet. Ie `Raleigh .

I have a lot of people now asking advise I suggest they join us on here

I'm completely mystified as to how it can work with only 3 wires, unless it takes power through the CANbus wires, which is generally not recommended. Can anybody figure it out?

 

[matthewslack]

Is there a battery in the display, so that +5 isn't needed?
Or is it using single direction comms so that only 1 comms wire is needed?
Or a special single wire comms protocol?

I've no idea what they are doing, but it is possible. My Shimano display manages power and comms over just two wires between motor and display.