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SW900 Display

Zuki

🧲 New user
Joined
Sep 13, 2025
Messages
10
Location
Japan
I got my new JN controller and unfortunately there's no compatible display except the SW900 Display. But I can't locate the problem of ERROR 30. I already checked all possible faults of wirings but still I can't fix the ERROR 30 . Anyone might have any idea how to fix this? Thank you
 
I got my new JN controller and unfortunately there's no compatible display except the SW900 Display. But I can't locate the problem of ERROR 30. I already checked all possible faults of wirings but still I can't fix the ERROR 30 . Anyone might have any idea how to fix this? Thank you
Can you post a link to the new controller?
 
I got my new JN controller and unfortunately there's no compatible display except the SW900 Display.
On the same page as the controller you linked, there was another kit listed using the same controller and another display (S866) besides the SW900, so it looks like other JN controllers that are compatible with several display models.

The issue with the SW900 is that there are different versions of firmware that are compatible with other manufacturers models like Lishui or Sabvoton. Did you purchase the controller and display together as a pair, or were they separate listings?

 
I got my new JN controller and unfortunately there's no compatible display except the SW900 Display. But I can't locate the problem of ERROR 30. I already checked all possible faults of wirings but still I can't fix the ERROR 30 . Anyone might have any idea how to fix this? Thank you
30 is usually comm error. If you are *certain* that all wiring is correct and can verify that data is being transmitted on both comm wires, that most often means the controller and display are not compatible and are "speaking different languages" to each other.

Displays and controllers are best purchased as a kit together.

There are numerous different firmwares even for the same hardwares, and each one could have a different set of data it transmits, and can even use different protocols, etc. Most of the time, this can't be changed to make incompatible parts compatible. :(

Additionally, not every controller, even if it has a connector for a display, can actually work with one--some simply don't have the firmware to talk to one.
 
Amazon | VGEBY 電動自転車コントローラー ブラシレスモーター コントローラー 24V 36V 48V 500W 750W 3モード正弦波26A修正アクセサリー E-bikeコンバージョンアクセサリー | VGEBY | 電動自転車
Note:
It must match the second communication protocol meter to use.

see the description at Amazon, as always with the chinese translation a littly cryptic, but protocol No2 is used by the controller. So you'll need a display, that "speaks" No2, like the S866, EN06 and many others. Your SW900 has a firmware that "speaks" 5s obviously ;)
You could check that by listening to the byte stream from the display with a USB to UART converter, both protocols are well known.
 
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On the same page as the controller you linked, there was another kit listed using the same controller and another display (S866) besides the SW900, so it looks like other JN controllers that are compatible with several display models.

The issue with the SW900 is that there are different versions of firmware that are compatible with other manufacturers models like Lishui or Sabvoton. Did you purchase the controller and display together as a pair, or were they separate listings?

Actually bought it separately. And I already bought the S886 But when I turn it on the wheels running already sir.
 
Ok sir . I will try again my S866 .
see the description at Amazon, as always with the chinese translation a littly cryptic, but protocol No2 is used by the controller. So you'll need a display, that "speaks" No2, like the S866, EN06 and many others. Your SW900 has a firmware that "speaks" 5s obviously ;)
You could check that by listening to the byte stream from the display with a USB to UART converter, both protocols are well known.
 
30 is usually comm error. If you are *certain* that all wiring is correct and can verify that data is being transmitted on both comm wires, that most often means the controller and display are not compatible and are "speaking different languages" to each other.

Displays and controllers are best purchased as a kit together.

There are numerous different firmwares even for the same hardwares, and each one could have a different set of data it transmits, and can even use different protocols, etc. Most of the time, this can't be changed to make incompatible parts compatible. :(

Additionally, not every controller, even if it has a connector for a display, can actually work with one--some simply don't have the firmware to talk to one.
Yes noted. It's my first time to DIY this thing but noted sir.
 
Actually bought it separately. And I already bought the S886 But when I turn it on the wheels running already sir.
The on and I off function involves no data transfer/communication, so no bearing on compatability. You might be able to buy one of the other displays for JN controllers from Amazon, and return it if it doesn’t work.
 
Actually bought it separately. And I already bought the S886 But when I turn it on the wheels running already sir.
The S886 is often used with self learning controllers. When you turn the display on, the motor will spin if the two self-learning wires from the controller are connected. The procedure is to power up the controller with these wires connected. Then the wheel spins. Next, you disconnect those two wires and shut down. Then when you power up again, it will work normally,

Looking at your VGEBY picture, there appear to be two single white wires with matching connectors. I would say those are the self learning wires.
 
The sulotion of this problem using SW900 is useless it's better use S866 dipslay for those who using JN controller 26A just change the protocol.
 
Hello can you help me.who knows the wiring diagram
 
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those controller have very similar wiring, i suggest that you check similar ones for sale advertised with wire description and compare with yours. Sometimes the electronic board have short description inside for each wires but it is tricky to read without unsoldering wires....Try this and let us know your progress and if some remain unknown...
-Naturaly bigger wires are power and motor.
-The hall are grouped 5-6 pins
-the single red is the on/off with many different name...

Group of 3 are most of the time throtle or 3 speed switch.
-throtle has fixed 0v and +5v while the third is the wipper signal
-3 speeds has a common wire and 2 return to select speed by shorting common with one of the other

the 2 wires set on a single connector are harder to figure out
-Low voltage for brakes switch stop when shorted. (often it would be doubled for each handle)
-Could be output for lights that give battery voltage and ground when turned on
-Could be other options like cruise, reverse etc
-Motor learning is usually to connector male + female to jump toghether

Single wire
-High voltage brake to receive battery voltage to stop controller
-display single wire

There is more options but that is the one i think of
 
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Hello can you help me.who knows the wiring diagram
I merged this post with your other thread, since you just posted it as a thread called "wiring", and don't tell us anything about what you want the wiring diagram for.

Since there are about 10billion billion things with wiring diagrams, and no one can help you figure out waht it would be unless you tell us exactly what it is you need it for, including all the devices you want to connect to each other, we can either assume that it is about the same problem you already had, and so it belongs here, or it's for something completely different, in whcih case you'll need to provide the *complete* details about it so we can start helping.
 
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