Home Assistant Add-on: BatMON

Monitor and control various Battery management systems (BMS) over Bluetooth. This add-on reads the BMS and sends sensor data through MQTT to Home Assistant. Using bluetooth on the Home Assistant host system, it does not need any additional hardware.

I created this to compare BMS readings for a detailed evaluation of BMS reliability and accuracy.

Features

• Uses Bluetooth Low-Energy (BLE) for wireless communication
• Records SoC, Current, Power, individual cell voltages and temperatures
• Monitor multiple devices at the same time
• Energy consumption meters (using trapezoidal power integrators)
• Control BMS charging and discharging switches
• Home Assistant MQTT Discovery

Supported Devices (bluetooth)

• JK BMS (jikong) (JK02 protocol)
• Daly BMS
• JBD / Xiaoxiang BMS
• Victron SmartShunt (make sure to update to latest firmware and enable GATT in the VictronConnect app)

I tested the add-on on a Raspberry Pi 4 using Home Assistant Operating System.

Installation

• Go to your Home Assistant Add-on store and add this repository: https://github.com/fl4p/home-assistant-addons
• Install Batmon add-on
• Install, configure and start Mosquito MQTT broker (don't forget to configure the MQTT integration)

Configuration

The add-on can read multiple BMS at the same time. Add an entry for each device, such as:

- address: CC:44:8C:F7:AD:BB
  type: jk
  alias: battery1

address is the MAC address of the Bluetooth device. If you don't know the MAC address start the add-on, and you'll find a list of visible Bluetooth devices in the add-on log. Alternatively you can enter the device name here as displayed in the discovery list.

type can be jk, jbd, daly, victron or dummy.

With the alias field you can set the name as displayed in Home Assistant. Otherwise, the name as found in Bluetooth discovery is used.

If the device requires a PIN when pairing add pin: 123456 (and replace 123456 with device's PIN)

For verbose logs of particular BMS add debug: true.

• Set MQTT user and password. MQTT broker is usually core-mosquitto.
• concurrent_sampling tries to read all BMSs at the same time (instead of a serial read one after another). This can increase sampling rate for more timely-accurate data. Might cause Bluetooth connection issues if keep_alive is disabled.
• keep_alive will never close the bluetooth connection. Use for higher sampling rate. You will not be able to connect to the BMS from your phone anymore while the add-on is running.
• sample_period is the time in seconds to wait between BMS reads. Small periods generate more data points per time.
• Set publish_period to a higher value than sample_period to throttle MQTT data, while sampling BMS for accurate energy meters.
• invert_current changes the sign of the current. Normally it is positive during discharge, inverted its negative.
• expire_values_after time span in seconds when sensor values become "Unavailable"
• watchdog stops the program on too many errors (make sure to enable the Home Assistant watchdog to restart the add-on after it exists)

Troubleshooting

• When experiencing connection issues enable keep_alive
• Enable verbose_log and check the logs. If that is too noisy set debug: true in the BMS configuration as described above
• Power cycle the BMS Bluetooth dongle (or BMS)
• Try another Bluetooth hardware
• Try to find the BMS with a BLE scan linux

Known Issues

• After a long-lasting bluetooth connection is lost both Daly and JBD dongles occasionally refuse to accept new connections and disappear from bluetooth discovery. Remove wires from the dongle and reconnect for a restart.
• Raspberry PI's bluetooth can be buggy. If you experience errors and timeouts try to install an external Bluetooth dongle.

TODO

• use the new Bluetooth integration since HA 2022.8 https://www.home-assistant.io/integrations/bluetooth/

Stand-alone

You can run the add-on outside of Home Assistant (e.g. on a remote RPI sending MQTT data of WiFI). See doc/Standalone.md

References

• dalybms: similar add-on
• JK-BMS: similar add-on using ESP-Home (needs extra hardware)
• Daly_RS485_UART_Protocol.pdf
• JK-bms esphome
• JK02 protocol