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No battery recognized with JK-BMS v15.41 and RS485 #419

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No battery recognized with JK-BMS v15.41 and RS485#419
#428
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supportSupport request
@hsteinhaus

Description

@hsteinhaus
hsteinhaus
opened on Mar 16, 2026

Describe the problem

I would like to connect my four JK-BMS batteries via RS485. No communication, no batteries detected, see log below.

The batteries are running fine, when configured as JK master-slave system, and also with dbus-serial-battery when using BLE communications. The latter is a bit unreliable though, with a "BMS cable" error every couple of days. That is why I would like to switch to a proper wired connection.

The USB-RS485 adapter is the one supplied with the battery boxes. It is known to work without any issues with the config software provided by JK.

Installation method

Install script present in the driver folder

Driver version of the currently installed driver

v2.1.20260209dev, also tried latest v2.0.20250729

Driver version of the last known working driver

v2.1.20260209dev and release v2.0.20250729

Venus OS device type

Cerbo GX

Venus OS version

v3.67

Venus OS image type

Large

BMS type

JK Inverter BMS (JKBMS PB Model)

Cell count

16

Battery count

4

Connection type

Serial USB adapter to RS485

USB hub

Yes, no external power supply

Config file

[DEFAULT]
LOGGING = DEBUG
BMS_TYPE = Jkbms_pb
BATTERY_ADDRESSES = 0x01, 0x02, 0x03, 0x04
MODBUS_ADDRESSES = 0x01, 0x02, 0x03, 0x04

Driver startup log

2026-03-16 07:59:38.216338500 INFO:SerialBattery:Starting dbus-serialbattery
2026-03-16 07:59:38.218915500 INFO:SerialBattery:Venus OS v3.67 (large) running on Cerbo GX
2026-03-16 07:59:38.219554500 INFO:SerialBattery:dbus-serialbattery v2.1.20260209dev
2026-03-16 07:59:54.221215500 INFO:SerialBattery:-- Testing BMS: 1 of 3 rounds
2026-03-16 07:59:54.228680500 INFO:SerialBattery:  Testing Jkbms_pb at address "\x01" with 115200 baud
2026-03-16 07:59:54.228690500 DEBUG:SerialBattery:Jkbms_pb init
2026-03-16 07:59:54.550606500 INFO:SerialBattery:  |- No battery recognized
2026-03-16 07:59:55.056147500 INFO:SerialBattery:
2026-03-16 07:59:55.057132500 INFO:SerialBattery:-- Testing BMS: 2 of 3 rounds
2026-03-16 07:59:55.058015500 INFO:SerialBattery:  Testing Jkbms_pb at address "\x01" with 115200 baud
2026-03-16 07:59:55.058762500 DEBUG:SerialBattery:Jkbms_pb init
2026-03-16 07:59:55.373416500 INFO:SerialBattery:  |- No battery recognized
2026-03-16 07:59:55.879905500 INFO:SerialBattery:
2026-03-16 07:59:55.880508500 INFO:SerialBattery:-- Testing BMS: 3 of 3 rounds
2026-03-16 07:59:55.881234500 INFO:SerialBattery:  Testing Jkbms_pb at address "\x01" with 115200 baud
2026-03-16 07:59:55.882027500 DEBUG:SerialBattery:Jkbms_pb init
2026-03-16 07:59:56.214298500 INFO:SerialBattery:  |- No battery recognized
2026-03-16 07:59:56.723861500 WARNING:SerialBattery:No battery connection at /dev/ttyUSB0 and this address 0x01
2026-03-16 07:59:56.725178500 INFO:SerialBattery:-- Testing BMS: 1 of 3 rounds
2026-03-16 07:59:56.725987500 INFO:SerialBattery:  Testing Jkbms_pb at address "\x02" with 115200 baud
2026-03-16 07:59:56.726580500 DEBUG:SerialBattery:Jkbms_pb init
2026-03-16 07:59:57.045928500 INFO:SerialBattery:  |- No battery recognized
2026-03-16 07:59:57.551829500 INFO:SerialBattery:
2026-03-16 07:59:57.560060500 INFO:SerialBattery:-- Testing BMS: 2 of 3 rounds
2026-03-16 07:59:57.560069500 INFO:SerialBattery:  Testing Jkbms_pb at address "\x02" with 115200 baud
2026-03-16 07:59:57.560073500 DEBUG:SerialBattery:Jkbms_pb init
2026-03-16 07:59:57.899455500 INFO:SerialBattery:  |- No battery recognized
2026-03-16 07:59:58.410076500 INFO:SerialBattery:
2026-03-16 07:59:58.410084500 INFO:SerialBattery:-- Testing BMS: 3 of 3 rounds
2026-03-16 07:59:58.410087500 INFO:SerialBattery:  Testing Jkbms_pb at address "\x02" with 115200 baud
2026-03-16 07:59:58.410090500 DEBUG:SerialBattery:Jkbms_pb init
2026-03-16 07:59:58.765461500 INFO:SerialBattery:  |- No battery recognized
2026-03-16 07:59:59.270189500 WARNING:SerialBattery:No battery connection at /dev/ttyUSB0 and this address 0x02
2026-03-16 07:59:59.282665500 INFO:SerialBattery:-- Testing BMS: 1 of 3 rounds
2026-03-16 07:59:59.286030500 INFO:SerialBattery:  Testing Jkbms_pb at address "\x03" with 115200 baud
2026-03-16 07:59:59.286146500 DEBUG:SerialBattery:Jkbms_pb init
2026-03-16 07:59:59.600322500 INFO:SerialBattery:  |- No battery recognized
2026-03-16 08:00:00.122038500 INFO:SerialBattery:
2026-03-16 08:00:00.122045500 INFO:SerialBattery:-- Testing BMS: 2 of 3 rounds
2026-03-16 08:00:00.122048500 INFO:SerialBattery:  Testing Jkbms_pb at address "\x03" with 115200 baud
2026-03-16 08:00:00.124212500 DEBUG:SerialBattery:Jkbms_pb init
2026-03-16 08:00:00.457157500 INFO:SerialBattery:  |- No battery recognized
2026-03-16 08:00:00.962603500 INFO:SerialBattery:
2026-03-16 08:00:00.965311500 INFO:SerialBattery:-- Testing BMS: 3 of 3 rounds
2026-03-16 08:00:00.967747500 INFO:SerialBattery:  Testing Jkbms_pb at address "\x03" with 115200 baud
2026-03-16 08:00:00.968329500 DEBUG:SerialBattery:Jkbms_pb init
2026-03-16 08:00:01.293171500 INFO:SerialBattery:  |- No battery recognized
2026-03-16 08:00:01.811954500 WARNING:SerialBattery:No battery connection at /dev/ttyUSB0 and this address 0x03
2026-03-16 08:00:01.811963500 INFO:SerialBattery:-- Testing BMS: 1 of 3 rounds
2026-03-16 08:00:01.811966500 INFO:SerialBattery:  Testing Jkbms_pb at address "\x04" with 115200 baud
2026-03-16 08:00:01.811969500 DEBUG:SerialBattery:Jkbms_pb init
2026-03-16 08:00:02.123481500 INFO:SerialBattery:  |- No battery recognized
2026-03-16 08:00:02.651857500 INFO:SerialBattery:
2026-03-16 08:00:02.651865500 INFO:SerialBattery:-- Testing BMS: 2 of 3 rounds
2026-03-16 08:00:02.655524500 INFO:SerialBattery:  Testing Jkbms_pb at address "\x04" with 115200 baud
2026-03-16 08:00:02.658181500 DEBUG:SerialBattery:Jkbms_pb init
2026-03-16 08:00:02.996379500 INFO:SerialBattery:  |- No battery recognized
2026-03-16 08:00:03.509069500 INFO:SerialBattery:
2026-03-16 08:00:03.509077500 INFO:SerialBattery:-- Testing BMS: 3 of 3 rounds
2026-03-16 08:00:03.509080500 INFO:SerialBattery:  Testing Jkbms_pb at address "\x04" with 115200 baud
2026-03-16 08:00:03.509082500 DEBUG:SerialBattery:Jkbms_pb init
2026-03-16 08:00:03.840269500 INFO:SerialBattery:  |- No battery recognized
2026-03-16 08:00:04.346636500 WARNING:SerialBattery:No battery connection at /dev/ttyUSB0 and this address 0x04
2026-03-16 08:00:04.347777500 ERROR:SerialBattery:>>> No battery connection at /dev/ttyUSB0 and this bus addresses: 0x01, 0x02, 0x03, 0x04
2026-03-16 08:00:04.353794500 INFO:SerialBattery:Exit signal received, exiting gracefully...
2026-03-16 08:00:04.355866500 INFO:SerialBattery:Stopped dbus-serialbattery with exit code 1
2026-03-16 08:04:18.853191500 *** CCGX booted (0) ***

Relevant log output

The master (normally at id #0) was reconfigured into a slave at id #4 during the tests. I also repeated the test with only one of the slave batteries connected (#3) - no change in behavior or in log output.

Logic analyser at hand for in-detail analysis if needed.

Any other information that may be helpful

No response

Please confirm that you have completed the following steps before submitting your support request

  • I have carefully read all the instructions above including the descriptions.
  • I have tried the nightly build first, if I was not already using it. This means the logs I provide are from the nightly build.
  • I have rebooted at least once after I saw the issue.
  • I have read the complete changelog.
  • I have provided the logfiles in the correct format with a HUMAN READABLE timestamp by piping it through tai64nlocal.
  • I have clicked all checkboxes because I did not read the instructions.

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