Smart Home Automation & Custom BMS Bridge

A residential client wanted complete home automation — gates, garage doors, motorised window blinds, lighting zones, and mood presets — integrated with their solar energy system. Home Assistant was the chosen platform, but two significant custom problems remained unsolved.

First, the client's lithium battery bank used a BMS that the inverter manufacturer did not support. The batteries and inverter could not communicate, which prevented the inverter from managing charge and discharge correctly. No off-the-shelf adapter existed for this combination.

Second, the BMS had no native dashboard — monitoring required a separate proprietary app that showed only basic data and no history. The client needed per-cell voltages, state of charge, temperature, and cycle counts visible on the same Home Assistant dashboard as the rest of the home.

We deployed Home Assistant on a dedicated server and integrated every controllable device in the home: two automated gates via MQTT-connected relay boards, three garage doors, twelve motorised blind zones on a custom RS485 bus, lighting groups via Zigbee, and multi-room audio. Mood scenes (Morning, Work, Evening, Cinema, Away) trigger coordinated state changes across all devices with a single tap.

For the BMS bridge, we wrote custom firmware running on a Raspberry Pi that reads the battery management system over BLE — decoding the proprietary protocol to extract per-cell voltages (15 cells per battery, 2 batteries), state of charge, current, temperature, MOS temperature, delta voltage, and cycle count. This data feeds into Home Assistant as native sensors, displayed on a custom Lovelace dashboard with real-time gauges and trend charts.

The Modbus-to-CAN bridge translates the battery state into the protocol the inverter expects — enabling correct charge profile selection, low-SoC cutoff, and grid-tie behaviour that would otherwise be impossible without supported hardware.

The system is now being re-engineered onto custom ESP32 hardware with a web dashboard for fleet deployment — tracking multiple installations globally with GPS location, live telemetry, and remote firmware updates.