Berger LFP BLE Flow

This is the app flow used to obtain battery information such as discharge current, SOC, voltage, temperatures, cell voltages, MOS state, and estimated charge/discharge time.

Evidence

App package: com.jbd.berger
Version: 1.0.3
Main bundle: assets/apps/__UNI__F61076D/www/app-service.js
Source-map style log labels embedded in bundle:
- utils/BLE.ts
- App.vue
- dashboard/control/parameter pages

Connection Sequence

uni.openBluetoothAdapter()
uni.startBluetoothDevicesDiscovery() with service filter ff00
uni.onBluetoothDeviceFound() records devices and RSSI
uni.createBLEConnection() with 10 second timeout
uni.getBLEDeviceServices()
uni.getBLEDeviceCharacteristics()
uni.notifyBLECharacteristicValueChange() on ff01
uni.onBLECharacteristicValueChange() buffers incoming bytes
uni.writeBLECharacteristicValue() sends command chunks to ff02 with writeType: "writeNoResponse"

The app chunks outgoing buffers into 20-byte pieces before writing.

Services And Characteristics

Service: 0000ff00-0000-1000-8000-00805f9b34fb
Notify/read: 0000ff01-0000-1000-8000-00805f9b34fb
Write: 0000ff02-0000-1000-8000-00805f9b34fb

Pairing / Bonding

Needs Android bond before normal telemetry: likely no.
Evidence: the app uses uni-app BLE APIs for connection, service discovery, notifications, and writes. I did not find a normal-path bond request in the app bundle.
Caveat: a peripheral firmware could still enforce encryption independently, but the app flow itself does not show pairing as a telemetry prerequisite.

Getting Live Values

The app sends:

DD A5 03 00 FF FD 77

The response uses:

DD 03 <status> <length> <payload> <checksum> 77

Important payload fields for command 0x03:

Payload bytes	Formula	Unit	Field
`0..1`	big-endian / 100	V	pack voltage
`2..3`	signed big-endian / 100	A	current
`4..5`	big-endian / 100	Ah	remaining capacity
`6..7`	big-endian / 100	Ah	nominal capacity
`8..9`	raw	cycles	cycle count
`10..11`	JBD bitfield	date	production date
`12..13`	nonzero bitmap	boolean	balancing
`16..17`	nonzero bitmap	boolean	protection
`18`	decimal digits	version	software version
`19`	raw	%	SOC
`20`	`1 = charge`, `2 = discharge`, `3 = both`	boolean	MOS state
`22`	raw count	count	temperature sensor count
`23..`	`(raw - 2731) / 10`	deg C	temperatures

Production date bitfield:

day = value & 0x1F
month = (value >> 5) & 0x0F
year = 2000 + (value >> 9)

Estimated time is computed locally:

if current_A > 0:
  time_to_full = (nominal_Ah - remaining_Ah) / current_A
if current_A < 0:
  time_to_empty = remaining_Ah / abs(current_A)

Cell Voltages