BMSC2MQTT

What The Device Does

• Reads BMS data via Bluetooth (BLE) or wired (UART/RS485), depending on BMS type.
• Shows live values in the web UI.
• Publishes data via MQTT (including Home Assistant Discovery when enabled).
• Supports OTA updates (online and manual).
• Uses a 5x WS2812 status LED strip.
• Optional: DS18B20 temperature sensors.
• Optional: relay outputs (depending on configuration).

Supported BMS (Current State)

BMS	Bluetooth (BLE)	Wired (UART/RS485)	Write (SOC/MOS)
Daly (Classic)	Yes	Yes	Yes
100B (Daly new map)	Yes (currently Daly BLE profile)	Yes	Yes (wired), BLE depends on device
JK	Yes	Yes	No (read-only)
JBD	Yes	No	MOS yes, SOC no
TDT	Yes	Yes	No (read-only, BLE unlock available)

Important:

• Write functions are only active when:
  • a valid license is present,
  • the BMS is connected,
  • and the selected provider supports that write operation.

Quick Start

1. Flash the firmware.
2. Power on the device.
3. If no WiFi is configured, the device starts an AP:
   • SSID: BMSC2MQTT_AP (or ${SOURCE_NAME}_AP)
   • IP: 192.168.4.1
4. Open http://192.168.4.1 in a browser.
5. Configure WiFi in Network Settings.
6. Optional: configure your broker in MQTT Settings.
7. Open Device Settings and run the BMS setup wizard:
   • Select link type: Bluetooth or Wired
   • Select BMS type
   • Test connection
   • Save
8. Check live values on the status page.

Note:

• In normal WiFi mode, the device is also reachable via mDNS, for example http://BMSC2MQTT.local (name is configurable).

Web UI Overview

• Status: live values, cell view, SOC bar, MOS switches (if unlocked).
• Network Settings: WiFi scan, SSID/password, optional BSSID lock, optional static IP.
• MQTT Settings: broker, port, topic, interval, TLS, HA discovery.
• Device Settings: BMS setup wizard and advanced BMS/UART settings.
• Firmware Update: online update (GitHub) and manual OTA update, plus backup/restore.
• License Settings: manage license key.
• Web Serial: live debug log in browser.

BMS Setup: Wizard + Advanced

Wizard (Recommended)

• Guides you step by step through:
  • link type
  • BMS type
  • scan/connect (BLE) or wiring test (wired)
  • save

Advanced

• For special setups:
  • bmsLink (BLE/Wired)
  • bmsVendor
  • UART pins (RX, TX, optional RTS/DE)
  • baud rate
  • BLE auto-reconnect and device selection

Practical notes:

• Daly/100B wired is usually direct TTL.
• For RS485 with transceiver, set RTS/DE pin (otherwise -1).

Important Runtime Mode: AP vs BLE

When Access Point mode is active (configuration mode), BLE-BMS is intentionally disabled.
Reason: stable WiFi/Bluetooth coexistence.

This means:

• No BLE-BMS connection/scan while in AP mode.
• BLE-BMS automatically resumes when the device returns to normal WiFi mode.

WS2812 Status LED Strip (Current Firmware Behavior)

The firmware uses 5 LEDs.

Boot

• Short boot animation: white running light, then off.

Status Mode

LED mapping:

• LED 0: WiFi/RSSI
• LED 1: Device/BMS status
• LED 2: MQTT status
• LED 3-4: off

Colors:

• WiFi/RSSI (LED 0):
  • Green for good signal (roughly better than -60 dBm)
  • Orange for mid-range signal (roughly -80 to -60 dBm)
  • Red for weak signal (roughly below -80 dBm)
  • If RSSI is not available yet: connected/disconnected only (green/red)
• Device (LED 1): green = OK, red = error/offline
• MQTT (LED 2): green = connected, red = disconnected

AP mode:

• LED 0 solid blue
• LED 2 off (MQTT is not evaluated in AP mode)

SOC Mode

When all required states are OK, the display switches to an SOC bar after 5 seconds:

• All 5 LEDs show charge level (including partial LED for intermediate values).
• Colors:
  • <= 10%: red
  • 11-30%: orange

  • 30%: gradient toward green

MQTT Behavior

The base topic is configurable (default: BMSC2MQTT).

Examples (publish, retained):

• <topic>/WiFiStatus
• <topic>/RSSI
• <topic>/DS18B20/<index>
• <topic>/bms/device
• <topic>/bms/connected
• <topic>/bms/live/*
• <topic>/bms/meta/*
• <topic>/bms/cells/*
• <topic>/bms/temps/*
• <topic>/bms/errors/text (only if not empty)

MQTT control topics (subscribe):

• <topic>/bms/control/soc
• <topic>/bms/control/power_in
• <topic>/bms/control/power_out

Payloads:

• soc: number (for example 50)
• power_in, power_out: true/false, 1/0, on/off
• null: resets the control value

License (What It Means For Users)

Without a license:

• Basic values stay visible (voltage, current, SOC, connection state, etc.).
• Detailed values can be limited (for example detailed cell/temperature data).
• Write functions (SOC/MOS) are locked.

With a valid license:

• Full data set (depending on BMS type).
• Write functions available if supported by the provider.

Firmware Update And Backup

• Online update: downloads OTA package from GitHub Releases.
• Manual update: upload OTA file in the UI (.ota recommended).
• Backup/Restore:
  • export settings as JSON
  • import later

Common Issues

• BLE scan finds no devices:

  • check if AP mode is active (BLE is disabled in AP mode)
  • select the correct BMS type
  • close the vendor app while scanning/connecting

• Wired connection shows no data:

  • check RX/TX wiring (not swapped)
  • check baud rate
  • for RS485, set RTS/DE pin correctly

• MOS/SOC controls cannot be used:

  • check license status
  • BMS must be connected
  • BMS type/provider must support writes

• DS18B20 shows -127:

  • sensor not detected or not connected

Summary

For normal commissioning, you only need to:

• configure WiFi
• configure MQTT (optional)
• run the BMS setup wizard

Everything else is available in the web UI.