Broken display EV-meter s890

[qvalff8]

Hi all,

I've been trying to get my old cargo bike back on the road. The display got rained on and stopped working 2+ years ago. Today I just started alligator clipping V+ (I assumed 5V, but it was battery voltage, 39V) to various pins, and I now have the throttle working, so the controller is still good, or at least not totally bad (I rode it and it accelerates as normal for full power, full throttle). Now I'd like to get the Peddle Assist System working again.

The display has 6 wires labelled
TX (grn), RX (blu), DD (yel), DS (whi), G (blk), and V+ (red).

I used an alligator clip to short V+ and DS. Like this, the throttle works, and accelerates the bike. PAS doesn't. It's also full power; I used to use either 2/5 or 3/5 bars of power setting as otherwise I go too fast on the local biking/walking path.

The s890 display is not the same as shows up on ebay by that name. It was used on the Biruni Scarlett ebike, as seen here:

Biruni Scarlett Review

Price: $2499 | Model Year: 2014 | Custom designed light weight electric cargo bike with unique asymmetrical step-through frame Powerful 500 watt high torque gearless direct drive rear hub motor is quiet, smooth and tough Front and rear racks, built directly from frame tubing offer plenty of...

electricbikereview.com

and here:

Google Image Result for https://electricbikereview.com/wp-content/assets/2015/11/black-biruni-scarlett-ev-meter.jpg

There are also 4 wires coming from a separate 3 button module
GND (blk), UP (grn), DOWN (blu) , SET (yel)

Would a controller like this one get my PAS system working, and with some choice of power level?:

6PIN S810 E-Bike Meter LED Display IP65 36V UART for Electric Bike Electric4276 | eBay

IP65 waterproof grade. Applicable handlebar: 22.2mm.

www.ebay.com

That shows 6 pins, and UART. How do I figure out if I need a UART or KT controller, or one with some other protocol?

In my attached photos, the black box is the unlabelled motor controller, the other two show the inside of the display/3 button module.

 

[qvalff8]

The controller has 4 cables coming out: 3 JULET connectors and an audio/aux-in style going to the PAS:

On the bottom end come out:
2 Pin for battery
9 pin for motor (3 fatter pins for I assume motor leads, 3 for hall sensor, and 3 for something else)

Out of the top end come out:
different style 9 pin (all skinny) JULET going to the throttle, brakes, and display. 1T5 9 pin
audio Aux-in-style going to the pedal assist sensor

The white wire which I shorted/jumpered to battery voltage in the display changes to purple before it goes into the controller. It goes far into the controller, as seen in the attached.
The red 36V wire in the display changes to brown and goes into Vcc in the controller

I tried to google SCIWE SW_LDS890_A7 for the display, but couldn't find anything

Inside the controller, the YJP32 didn't come up with anything either. The controller has 12 MOSFETS along one side, clamped to a the case on one side. X12TFG is other writing on the PCB. The T and F seem to combine to be one letter? But that didn't get me anywhere on google either.

I'm trying to go through the various controller threads to see one that might fit, but so far, I haven't come across anything that is (or, at least, appears to me) applicable.

 

[amberwolf]

The display has 6 wires labelled
TX (grn), RX (blu), DD (yel), DS (whi), G (blk), and V+ (red).

I used an alligator clip to short V+ and DS. Like this, the throttle works, and accelerates the bike. PAS doesn't. It's also full power; I used to use either 2/5 or 3/5 bars of power setting as otherwise I go too fast on the local biking/walking path.

I don't know your specific controller, but, it would be normal for most controllers to not have any PAS operation until you select an assist level on the display; some even disallow throttle until then, wiht "mode zero" being powered on but not operating the motor, a kind of "safe mode".

Many controllers always have full power range available on the throttle, while the assist modes restrict the simple on/off PAS so there is *some* pedal control of the speed or power (since speed of pedalling (cadence) doesn't control anything).


It could be that yours defaults without any display to tell it otherwise to do the latter, while with the display working it would be commanded not to.

The s890 display is not the same as shows up on ebay by that name. It was used on the Biruni Scarlett ebike, as seen here:

Unfortunately you don't show your display's front for us to attempt to match it to something. Only seeing the back of it doesn't help much. :/ If the links are supposed to show what yours looks like...I've never seen one like that.

But a number of Lishui controllers I've had used Kingmeter displays that have a nearly identical remote button unit to yours. The KM SW900 displays I've got don't look like your S890, though they make a number of designs.

FWIW, In searching for a pic of a km display like mine, I accidentally ran across this

Контроллер Volta 48V/600W с LCD дисплеем в комплекте

Контроллер Volta 48V/600W с LCD дисплеем в комплекте предназначен для регулирования скорости вращения редукторных и прямо-приводных мотор колёс, вентильных электродвигателей с датчиками Холла, имеющих номинальное напряжение 48 вольт и реализует мощность до 1296 ватт. Рекомендуется для...

voltabikes.com.ua

which has a controller / display set that includes a display that might be lke yours. You could see if they sell that separately.

A google image search for Kingmeter displays to show the variety; didn't see one like yours so probably not KM.

kingmeter lcd display - Google Search

There are also 4 wires coming from a separate 3 button module
GND (blk), UP (grn), DOWN (blu) , SET (yel)

Would a controller like this one get my PAS system working, and with some choice of power level?:

That's not a controller, it's a display.

The controller would be the (usually metal) box that most of the system wires converge on, and where both battery and motor connect to.

Based on what ohters have had good results with, either a KT or Lishui controller would probably work with a typical PAS cadence sensor, and have setup menus that let you choose some things about how the assist levels work, etc.

There's a bunch of threads about KT (kunteng, kun teng) and Lishui (LS, LiShui, Li Shui) controllers, including ones for open-source firmware you can install on them to greatly customize how they operate, vs the less customizable OEM firmware, if you find the need (probably not).

That shows 6 pins, and UART. How do I figure out if I need a UART or KT controller, or one with some other protocol?

UART is one possible serial "hardware" type for a display-controller connection. CANbus is another. There are also various comm protocols / datasets used between displays and controllers, making it complicated to figure out if any particular display will work on any particular controller.

Some display hardware supports multiple controllers, but may have to be factory set to a particular protocol / etc to work with one, while others may be user-settable.

Some controller hardware supports multiple display types.

None of htem that I know of support all of whatever the other one is.


It's safest to buy a "kit" that includes both as a set so you know they will work together. If you think you might have future problems with the display you might want to buy a spare at that same time from the same seller and make sure they understand you want it for *that* controller in case they also sell versions for other ones.

 

[derekderek]

this is a maybe. amazon display with different connector options. including a round 6 pin. https://www.amazon.com/Mcezdy-Protocol-Colorful-Computer-Charging/dp/B0D9B5YZK2/ref=sr_1_7_sspa?crid=2J643USI0ENQF&dib=eyJ2IjoiMSJ9.8MznbN7mbXw7gUQARc2Rnc-MQbMrIZbw3dFyigWpvxuTIw4EvUtCJTWzNS8CrB5F7sXuiz6mR8IeMdwt6Et3xUhPSR_TJiwnxMDqsqxqoNgatc-qSiBd-1lGGuRmu2gQReDCjb8BMko5L1oJKFXCBp4Tg0O2XyvH15fPANtx_zZBPOac4rwgBhR0wFYA28sDGdfk2qACccl5tw11-8FTgP9vFHNfCEQ2xjS6n_u2ByU.ItHsiLKdKejJQrOOsgmzq-rkU0ndXhZvbBpk-JR4HOw&dib_tag=se&keywords=ebike+controller+display+s890&qid=1746174040&sprefix=ebike+controller+display+s890,aps,230&sr=8-7-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9tdGY&psc=1 worth looking at to see if your display connector matches. and amazon if it doesn't work, return it... the first display you showed is the old 3 speed type. not really a display. just a mode switch and 4 led battery level. i would think S890 would be more likely to work with s900 or s866 protocols. NOT KT. but harder to find with the all-juliet style connectors. you may need a whole set that comes with throttle, PAS controller and display. many even come with brake levers.

 

[qvalff8]

Thank you everyone for your replies.

Here's a picture of the front of the display. Is there something to conclude from the Vss Vdd etc pin names on the front of the PCB?

Yeah my kit came with everything brake levers, throttle, display, display up/mode/down module, controller, hub motor wheel. The controller is actually the only thing that has the Julet connectors, the brake levers and display all combine in a weird waterproof-ish junction barrel thing. This is where they change colors (white soldered to purple for example). It'd be nice if the display had a julet connector instead of hard-wired.

I'm sure the date of 2012 means the protocols available at that time were slightly less numerous than today. I built the bike in 2017 or '18. The parts were ordered from ebay in ~2015. So this stuff is old. The SW900 controllers look the most like what I have, but they mostly seem to be 5 pin (except for the one Derek found). I'll consider ordering that one. But first I'll wait to see if the Ukrainian guy replies to my inquiry (in english).

 

[amberwolf]

Here's a picture of the front of the display. Is there something to conclude from the Vss Vdd etc pin names on the front of the PCB?

Not without a schematic to show all of what those signals connect to and what voltages they should all be, etc.

You can look up each term and make guesses, but you won't really *know* anything without testing a good one compared to a bad one.

I'm sure the date of 2012 means the protocols available at that time were slightly less numerous than today.

Older stuff actually means that it's more likely to be something custom specific for that display and controller (whatever the engineer at the time came up with), and less likely that anything else would work...protocols and whatnot are very slowly becoming standardized enough for at least the same brand to tend to work with it's own stuff, regardless of model, though even then all functionality may not be present with various combinations.

And for even some things to be intercompatible *between* brands, because they're not always jjust making it up as they go along now.


Hopefully you can just get the display from Ukraine (or find out where *they* got them from), and it is the same as what you have, not just looks the same.

 

[qvalff8]

After looking at the junction box/barrel picture more closely, I only have 5 wires. The yellow wire does not continue past the junction. The functional wires are:
TX (grn), RX (blu), DS (whi), G (blk), and V+ (red).
Green blue white black red. Those kinda match the SW900 from this thread: [SOLVED] 36V 22A Controller wiring questions.

So maybe I should order one of those and hope it works...

I looked through this thread and the photos show SCIWE also made that guys display:

SW900, S866, etc - Small connector (BROWN, WHITE) - for lights or relay?

HI all, Apologies if this is dealt with elsewhere. After replacing a failed controller (with one that was promised to be SW900-compatible, but really isn't), I decided to wire in the lights to the (battery voltage) 'lights' output of the controller, through a 48V->12V DC-DC converter...

endless-sphere.com

He also crossposted to pedelecs.co.uk: SW900, S866, etc - Small connector (BROWN, WHITE) - for lights or relay?
On that site, someone describes the back and forth between controller and display:
"The red wire going to the LCD has battery voltage, which is used to power the LCD when you press the power-on button. When you switch it on, the CPU in the LCD does two things: It latches the power on, and it switches a transistor to also latch it to the blue wire, which runs back to the controller and powers it."
I think the blue wire that goes back to the controller to turn it on is white/purple in my case, and by jumpering V_batt to it, I turn on the controller allowing me to use the throttle.

Is there a thread on displays comparing SW900 to S866 to 830 etc? Is the SW in SW900 for SciWe?
This thread is probably the best starting point for my needs, but if anyone has come across something better, please let me know:

Controller and Display manufacturers

I'm working on the section of my NEWB FAQ regarding displays. As far as compatibility is concerned, the general guidance is to purchase a controller and display together to ensure compatibility, and if purchasing separately, purchasing the same brand may provide a better chance of...

endless-sphere.com

I also found a v890 that might be what I need:

https://www.amazon.com/Electric-Display-Universal-Meter-Screen/dp/B0F1Y2KCSS

I guess there's no way to know whether I need an S(W)xxx display or a KT type or something completely different without trying each one. Any advice on which one to start the parts canon with appreciated.

 

[amberwolf]

I guess there's no way to know whether I need an S(W)xxx display or a KT type or something completely different without trying each one. Any advice on which one to start the parts canon with appreciated.

As old as it is, and given the manufacturer name not seen before, it's just as likely that it isn't any of those types, and is it's own custom one.

But as long as the signal levels are the same, wiring is done correctly, then it shouldn't hurt to try them. Just be very sure you aren't wiring any logic level stuff to any battery level stuff; it's easy to accidentally do, and typically "fatal" to the device.



FWIW, even different versions of the same display may function differently--I have at least a couple of the SW900 Kingmeter displays, and a few Lishui controllers that work with that type of display. Each combination of each display and controller has different menus that show up, different data in those menus, and different behavior with different assist levels / control inputs / etc that other combinations of these displays and controllers. Some of them show data on a menu but don't actualy change it when you exit the menus, while others do.

So...it's tough enough to predict how a system that you *know* works together will behave, much less one that you don't even know if they will work....

 

[qvalff8]

Okay, good news: I'm a bit of an idiot and didn't plug the PAS sensor plug (the audio-in type headphone jack thing) all the way in. It is waterproof and made an audible, satisfying click when I used a lot more force. Pedal assist now works on something like setting 2.5 out of 5, which is good enough for me. The bike is back to almost exactly as functional as it was before the display failed.

The diagnosis path was:
Read that KT type controllers can be run without a display if you short V_batt to DS and GND to RX
Try that, as well as GND to TX and RX to TX
Nothing changes (throttle still works, PAS doesn't)
unplug and replug everything and notice how the PAS sensor plug goes in much further
Pedal assist now works!
try without GND to RX or anything else
Still works, so it's probably not a KT type controller

I will probably buy a SW900 in the hope that I get full PAS level control back but I can wait a bit for that step. Having probably eliminated KT, I'll hope my controller is Lishui or JN compatible. I'll post back when, in due time, I take that step to see if one of the displays works for my controller

Thank you for your help and attention!