Arduino script with NimBLE to monitor JK-BMS

This project is a modified version of syssi/esphome-jk-bms, rewritten for Arduino using NimBLE. Usefull for v11 BMS

Features

• Real-time Monitoring:

  • All data that are also available via the app

  • Cell voltages, resistances, temperatures, battery voltage, current, state of charge and more

  • BMS settings and status flags.

• Control:

  • Turn Charging, Discharging, and Balancing ON/OFF for each BMS.

  • I plan to add more.

• System Information:

  • Uptime

  • Free heap memory

  • Sketch information

• Multi-BMS Support:

  • Monitor and control multiple BMS devices simultaneously.

• Web Interface:

  • Simple but not pretty web interface with all data and some switches.

  • A small file manager is included to handle web server files

  • Automatic refresh

Installation

• Get startet:

  • copy index.html + style.css + jk-bms.ino local

• Open the Project in Arduino IDE:

  • Open the jk-bms.ino file in the Arduino IDE.

• Install Required Libraries:

  • Install the libraries NimBLEDevice + ArduinoJson

  • All others are included in the IDE by default

• Edit settings:

  • WiFi SSID / Password + MAC from the BMS

• Upload the Sketch:

  • Connect your ESP32 to your computer.

  • Select the correct board and port in the Arduino IDE.

  • Upload the sketch to the ESP32.

• Access the Web Interface:

  • After the upload, the ESP32 will connect to your Wi-Fi and the IP will be displayed in the serial monitor.

  • Open a web browser and navigate to the IP address of the ESP32.

  • A small error message appears that no Index.html was found

  • Follow the link or use http://IP/fs to upload index.html + style.css to the ESP32

Examples

• Serial interface

📁 Click to show

rst:0x1 (POWERON_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0030,len:4916
load:0x40078000,len:16436
load:0x40080400,len:4
ho 8 tail 4 room 4
load:0x40080404,len:3524
entry 0x400805b8
..
WiFi connected
IP address: 
192.168.0.102
LittleFS Mounted Successfully
Initializing NimBLE Client...
Starting scan...
BLE Device found: Name: , Address: 27:74:79:c1:9a:a6, manufacturer data: 0600010f200283b89eafdb644a971466f6f372ef262acdf0eb0c92be0f
BLE Device found: Name: JK_BD4A20S4P, Address: 20:22:08:25:26:8b, manufacturer data: 4a4b0001, serviceUUID: 0xffe0
Found target device: 20:22:08:25:26:8b
Attempting to connect to 20:22:08:25:26:8b...
New client created.
Connected to 20:22:08:25:26:8b
Connected to: 20:22:08:25:26:8b RSSI: -41
Subscribed to notifications for 0xffe1
Writing register: address=0x97, value=0x00000000, length=0
Frame to be sent: AA 55 90 EB 97 00 00 00 00 00 00 00 00 00 00 00 00 00 00 11 
Notification received...
Handling notification...
Start of data frame detected.
Notification received...
Handling notification...
Continuing data frame...
New data available for parsing.
Device info frame detected.
Processing device info...
Raw data received:
55 AA EB 90 03 77 4A 4B 5F 42 44 34 41 32 30 53 
34 50 00 00 00 00 31 31 2E 58 57 00 00 00 31 31 
2E 32 35 00 00 00 90 C4 05 00 3A 00 00 00 4A 4B 
5F 42 44 34 41 32 30 53 34 50 00 00 00 00 31 32 
33 34 00 00 00 00 00 00 00 00 00 00 00 00 32 34 
30 39 32 37 00 00 32 30 38 32 33 32 31 34 33 39 
00 30 30 30 30 00 49 6E 70 75 74 20 55 73 65 72 
64 61 74 61 00 00 31 32 33 34 00 00 00 00 00 00 
00 00 00 00 00 00 49 6E 70 75 74 20 55 73 65 72 
64 61 74 61 00 00 7C F8 FF FF 1F 0D 00 00 00 00 
00 00 90 0F 00 00 00 00 C0 D8 03 00 00 00 00 01 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 FE 
0F 00 00 00 00 00 00 00 00 00 00 53 
  Vendor ID: JK_BD4A20S4P
  Hardware version: 11.XW
  Software version: 11.25
  Uptime: 378000 s
  Power on count: 58
  Device name: JK_BD4A20S4P
  Device passcode: 1234
  Manufacturing date: 240927
  Serial number: 2082321439
  Passcode: 0000
  User data: Input Userdata
  Setup passcode: 1234
Notification received...
Handling notification...
Writing register: address=0x96, value=0x00000000, length=0
Frame to be sent: AA 55 90 EB 96 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10 
20:22:08:25:26:8b connected successfully
Notification received...
Handling notification...
Start of data frame detected.
Notification received...
Handling notification...
Continuing data frame...
New data available for parsing.
BMS Settings frame detected.
Processing BMS settings...
Cell voltage undervoltage protection: 2.82V
Cell voltage undervoltage recovery: 2.85V
Cell voltage overvoltage protection: 4.20V
Cell voltage overvoltage recovery: 4.18V
Balance trigger voltage: 0.01V
Power off voltage: 2.80V
Max charge current: 25.00A
Charge overcurrent protection delay: 30.00s
Charge overcurrent protection recovery time: 60.00s
Max discharge current: 40.00A
Discharge overcurrent protection delay: 300.00s
Discharge overcurrent protection recovery time: 60.00s
Short circuit protection recovery time: 60.00s
Max balance current: 0.40A
Charge overtemperature protection: 70.00C
Charge overtemperature protection recovery: 60.00C
Discharge overtemperature protection: 70.00C
Discharge overtemperature protection recovery: 60.00C
Charge undertemperature protection: -20.00C
Charge undertemperature protection recovery: -10.00C
Power tube overtemperature protection: 100.00C
Power tube overtemperature protection recovery: 80.00C
Cell count: 9
Total battery capacity: 40.00Ah
Short circuit protection delay: 1500.00us
Balance starting voltage: 3.00V
Notification received...
Handling notification...
Notification received...
Handling notification...
Start of data frame detected.
Notification received...
Handling notification...
Continuing data frame...
New data available for parsing.
Cell data frame detected.
Parsing data...

--- Data from 20:22:08:25:26:8b ---
Cell Voltages:
  Cell 01: 3.695 V
  Cell 02: 3.696 V
  Cell 03: 3.696 V
  Cell 04: 3.698 V
  Cell 05: 3.697 V
  Cell 06: 3.701 V
  Cell 07: 3.700 V
  Cell 08: 3.700 V
  Cell 09: 3.696 V
  Cell 10: 0.000 V
  Cell 11: 0.000 V
  Cell 12: 0.000 V
  Cell 13: 0.000 V
  Cell 14: 0.000 V
  Cell 15: 0.000 V
  Cell 16: 0.000 V
wire Resist:
  Cell 01: 0.321 Ohm
  Cell 02: 0.326 Ohm
  Cell 03: 0.332 Ohm
  Cell 04: 0.325 Ohm
  Cell 05: 0.310 Ohm
  Cell 06: 0.314 Ohm
  Cell 07: 0.314 Ohm
  Cell 08: 0.312 Ohm
  Cell 09: 0.313 Ohm
  Cell 10: 0.000 Ohm
  Cell 11: 0.000 Ohm
  Cell 12: 0.000 Ohm
  Cell 13: 0.000 Ohm
  Cell 14: 0.000 Ohm
  Cell 15: 0.000 Ohm
  Cell 16: 0.000 Ohm
Average Cell Voltage: 3.70V
Delta Cell Voltage: 0.01V
Balance Curr: 0.00A
Battery Voltage: 33.28V
Battery Power: 0.00W
Charge Current: 0.00A
Charge: 77%
Capacity Remain: 30.81Ah
Nominal Capacity: 40.00Ah
Cycle Count: 0.00
Cycle Capacity: 0.05Ah
Temperature T1: 22.0C
Temperature T2: 22.9C
Temperature MOS: 28.1C
Uptime: 4d 9h 4m
Charge: 1
Discharge: 1
Balance: 0
Balancing Action: 0
Notification received...
Handling notification...
Ignoring notification. Remaining: 9
Notification received...
Handling notification...
Ignoring notification. Remaining: 8
Notification received...
Handling notification...
Ignoring notification. Remaining: 7
Notification received...
Handling notification...
Ignoring notification. Remaining: 6
Notification received...
Handling notification...
Ignoring notification. Remaining: 5
Notification received...
Handling notification...
Ignoring notification. Remaining: 4
Notification received...
Handling notification...
Ignoring notification. Remaining: 3
Notification received...
Handling notification...

• Web interface

Disclaimer

This is an experimental project. Use it at your own risk.

Credits

Based on the work of syssi.