Component still under testing - No guarantee on full functionality

ESPHome Daly BMS Multi-Device Component

Advanced ESPHome component supporting multiple Daly BMS units on a shared RS485 bus with centralized UART dispatch.

⚠️ Personal Use Only - Not for commercial use without permission. See License section.

Features

• ✅ Multi-BMS Support - Connect 2+ Daly BMS units on the same RS485 bus
• ✅ Centralized Dispatcher - No packet collisions or data loss
• ✅ Individual Addressing - Each BMS has unique command and response addresses
• ✅ Full Sensor Support - Voltage, current, SOC, temperatures, cell voltages, and more
• ✅ Configurable Update Intervals - Optimize polling frequency per BMS
• ✅ Detailed Logging - Debug support for troubleshooting

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Table of Contents

• Why This Component?
• Architecture
• Hardware Requirements
• Installation
• Configuration
• Supported Sensors
• Troubleshooting
• Contributing
• License

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Why This Component?

The standard Daly BMS component in ESPHome cannot handle multiple BMS units on the same RS485 bus because:

1. Shared UART Buffer - Both BMS instances read from the same buffer, causing packet collisions
2. Hardcoded Response Address - Original component expects responses only from address 0x01
3. No Packet Routing - No mechanism to route responses to the correct BMS instance

This Component Solves These Issues:

• Centralized Dispatcher reads all UART data and routes packets to the correct BMS instance
• Configurable Response Addresses allow each BMS to filter its own responses
• Zero Packet Loss - Every response reaches its intended BMS instance

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🏗️ Architecture

┌─────────────────────────────────────────────┐
│           ESP32 / ESPHome                   │
│                                             │
│  ┌──────────────────────────────────────┐  │
│  │   DalyBmsDispatcher (Singleton)      │  │
│  │   - Reads UART buffer                │  │
│  │   - Identifies response address      │  │
│  │   - Routes to correct BMS instance   │  │
│  └──────────────┬───────────────────────┘  │
│                 │                           │
│       ┌─────────┴─────────┐                │
│       │                   │                │
│  ┌────▼─────┐      ┌─────▼────┐           │
│  │  BMS1    │      │  BMS2    │           │
│  │ (0x40→   │      │ (0x41→   │           │
│  │  0x01)   │      │  0x02)   │           │
│  └────┬─────┘      └─────┬────┘           │
│       │                  │                 │
└───────┼──────────────────┼─────────────────┘
        │                  │
        │     RS485 Bus    │
        │                  │
    ┌───▼──┐           ┌───▼──┐
    │ BMS1 │           │ BMS2 │
    │ Daly │           │ Daly │
    └──────┘           └──────┘

Communication Flow:

1. BMS Instance requests data (e.g., A5 40 90 ... for BMS1)
2. Dispatcher sends request via UART
3. Physical BMS responds (e.g., A5 01 90 ...)
4. Dispatcher reads response, identifies address (0x01)
5. Dispatcher routes to correct BMS instance (BMS1)
6. BMS Instance processes data and publishes sensors

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Hardware Requirements

Required Hardware:

• ESP32 or ESP8266 board
• RS485 to TTL converter (e.g., MAX485, MAX3485)
• 2 or more Daly BMS units with RS485 interface
• Shared RS485 bus connecting all BMS units

RS485 Wiring:

ESP32          RS485 Module      BMS1 & BMS2
──────         ────────────      ───────────
GPIO17  ──────> TX (DI)          
GPIO16  <────── RX (RO)          
                   A    ─────────> A (all BMS)
                   B    ─────────> B (all BMS)
GND     ───────> GND   ─────────> GND

BMS Configuration:

Each BMS must be configured with unique addresses:

• BMS1: Command Address = 0x40, Response Address = 0x01
• BMS2: Command Address = 0x41, Response Address = 0x02
• BMS3: Command Address = 0x42, Response Address = 0x03 (if needed)

Note: Use the Daly BMS PC software or Bluetooth app to set these addresses.

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Installation

1. Download Component

Clone this repository or download as ZIP:

git clone https://github.com/Kicosta/esphome-daly-bms-multi.git

2. Extract to ESPHome Directory

Extract the component to your ESPHome configuration directory:

# If using Home Assistant Add-on
unzip esphome-daly-bms-multi.zip -d /config/esphome/my_components/

# If using standalone ESPHome
unzip esphome-daly-bms-multi.zip -d ~/esphome/my_components/

Verify directory structure:

my_components/
├── daly_bms/
│   ├── __init__.py
│   ├── daly_bms.h
│   ├── daly_bms.cpp
│   ├── sensor.py
│   ├── binary_sensor.py
│   └── text_sensor.py
└── daly_bms_dispatcher/
    ├── __init__.py
    ├── daly_bms_dispatcher.h
    └── daly_bms_dispatcher.cpp

3. Reference in ESPHome Config

Add to your .yaml file:

external_components:
  - source:
      type: local
      path: my_components
    components: [daly_bms, daly_bms_dispatcher]

---

Configuration

Minimal Configuration

esphome:
  name: battery-monitor

esp32:
  board: esp32dev

# External components
external_components:
  - source:
      type: local
      path: my_components
    components: [daly_bms, daly_bms_dispatcher]

# UART for RS485
uart:
  id: uart_bus
  tx_pin: GPIO17
  rx_pin: GPIO16
  baud_rate: 9600

# Dispatcher (singleton - configure once)
daly_bms_dispatcher:
  id: bms_dispatcher
  uart_id: uart_bus

# BMS instances
daly_bms:
  - id: bms1
    dispatcher_id: bms_dispatcher
    address: 0x40              # Command address
    response_address: 0x01     # Response address
    update_interval: 8s
    
  - id: bms2
    dispatcher_id: bms_dispatcher
    address: 0x41
    response_address: 0x02
    update_interval: 9s

# Sensors
sensor:
  - platform: daly_bms
    bms_daly_id: bms1
    voltage:
      name: "BMS1 Voltage"
    current:
      name: "BMS1 Current"
    battery_level:
      name: "BMS1 SOC"
    
  - platform: daly_bms
    bms_daly_id: bms2
    voltage:
      name: "BMS2 Voltage"
    current:
      name: "BMS2 Current"
    battery_level:
      name: "BMS2 SOC"

Full Configuration Example

See example.yaml for a complete configuration with all sensors.

---

Supported Sensors

Sensor Platform

Sensor	Description	Unit
voltage	Total pack voltage	V
current	Pack current (+ charge, - discharge)	A
battery_level	State of Charge (SOC)	%
max_cell_voltage	Highest cell voltage	V
max_cell_voltage_number	Cell number with highest voltage	-
min_cell_voltage	Lowest cell voltage	V
min_cell_voltage_number	Cell number with lowest voltage	-
max_temperature	Highest temperature	°C
max_temperature_probe_number	Probe number with highest temp	-
min_temperature	Lowest temperature	°C
min_temperature_probe_number	Probe number with lowest temp	-
remaining_capacity	Remaining capacity	Ah
cells_number	Number of cells in series	-
temperature_1	Temperature sensor 1	°C
temperature_2	Temperature sensor 2	°C
cell_1_voltage to cell_16_voltage	Individual cell voltages	V

Binary Sensor Platform

Sensor	Description
charging_mos_enabled	Charge MOS status
discharging_mos_enabled	Discharge MOS status

Text Sensor Platform

Sensor	Description
status	BMS status (Stationary/Charging/Discharging)

---

Troubleshooting

Problem: "Could not find init.py for daly_bms_dispatcher"

Cause: Incorrect directory structure.

Solution: Ensure two separate directories exist:

ls my_components/daly_bms/__init__.py          # Must exist
ls my_components/daly_bms_dispatcher/__init__.py  # Must exist

---

Problem: "BMS2 sensors always show 'unavailable'"

Cause: Response address mismatch or dispatcher not configured.

Solution:

1. Check YAML configuration:

   daly_bms:
     - id: bms2
       response_address: 0x02  # Must match BMS physical setting!

2. Verify BMS hardware address using Daly PC software

3. Check logs for:

   [V][daly_bms_dispatcher]: Dispatching frame to BMS instance (response_addr=0x02)
   

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Problem: Data updates very slowly

Cause: Update intervals too long.

Solution: Reduce update_interval:

daly_bms:
  - id: bms1
    update_interval: 8s  # Faster updates

Recommended intervals:

• 5-10s: Real-time monitoring, active charging/discharging
• 20-30s: Balanced (recommended)
• 60s: Low-frequency monitoring, energy saving

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Problem: Compilation errors about missing methods

Cause: Old ESPHome version or cache issues.

Solution:

# Clean build cache
esphome clean your-config.yaml

# Update ESPHome
pip3 install -U esphome

# Recompile
esphome compile your-config.yaml

---

Debug logging

logger:
  level: VERBOSE

Useful log patterns:

# Dispatcher receiving and routing
[V][daly_bms_dispatcher]: Complete frame received: addr=0x01, len=13
[V][daly_bms_dispatcher]: Dispatching frame to BMS instance (response_addr=0x01)

# BMS processing frame
[V][daly_bms]: Processing frame for BMS addr=0x40, response_addr=0x01

# Sensor updates
[D][sensor]: 'BMS1 Voltage': Sending state 54.20V

---

Performance Tuning

Update Interval Recommendations

Scenario	BMS1	BMS2	Bus Load	Notes
Real-time	5s	6s	~52%	For active monitoring
Balanced ⭐	8s	9s	~33%	Recommended
Efficient	20s	20s	~14%	Low power
Power Saving	60s	60s	~5%	Minimal updates

Best Practices:

1. Stagger intervals (e.g., 8s and 9s) to avoid simultaneous polling
2. Start with 20s, reduce if you need faster updates
3. Monitor logs for timeout warnings
4. Avoid intervals < 5s unless necessary

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Contributing

Contributions are welcome! Please:

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

Development Setup

# Clone repository
git clone https://github.com/Kicosta/esphome-daly-bms-multi.git
cd esphome-daly-bms-multi

# Test with ESPHome
esphome compile example.yaml

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⚖️ License Notice

This component is provided for personal, non-commercial use only under CC BY-NC-SA 4.0.

Permitted:

• Home automation projects
• Personal learning and experimentation
• Sharing modifications with the community

Not Permitted:

• Commercial products or services
• Paid installations or consulting
• Resale or redistribution in commercial packages

For commercial licensing, contact: [kicosta@hotmail.com]

See LICENSE for full terms.

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Acknowledgments

• Original Daly BMS component by @s1lvi0
• Multi-BMS dispatcher architecture by Kicosta
• ESPHome community for the excellent platform

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Related Projects

• ESPHome - The platform this component is built for
• Home Assistant - Home automation platform
• Original Daly BMS Component

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** If this component helped you, please star the repository!**

• dispatcher.py - Configurazione dispatcher
• sensor.py, binary_sensor.py, text_sensor.py - Sensori