REC BMS for Home Assistant

This is a Non official custom integration for Home Assistant via HACS to surface REC BMS (Battery Management System)

Supported Entities

This allows you home assistant to connect to REC BMS sensor and display:

• Time remaining (Hours)
• Minimum cell voltage (Voltage)
• Maximum cell voltage" (Voltage)
• Battery current (Amps)
• Max Temperature (C)
• Pack Voltage" (Voltage)
• State of Charge (Percent)
• State of Health (Percent)

Example in Lovelave when using the sensors out of the box:

Install

Install via HACS

• The installation is done inside HACS (Home Assistant Community Store). If you don't have HACS, you must install it before adding this integration. Installation instructions here.
• Once HACS is installed, search for recbms
  • Navigate to the 'Integrations' tab in HACS, click explore & Download and search for the 'recbms' integration there. On the next screen, select "Download". Once fully downloaded, restart HomeAssistant.
• In the sidebar, click 'Configuration', then 'Devices & Services'. Click the + icon to add "recbms" to your Home Assistant installation.
  • Enter the host or IP of your RECBMS websocket (the ip or host and it ends with "/ws")
  • Enter the name you want to show for your REC BMS

Configuration

You need to suply the URL for the websocket that REC wifi exposes. You can use any tool (ex: postman) to directly connect to the websocket. For example "ws://192.168.8.2:80/ws" it should return two types of messages

REC BMS Websocket messages

Example of messages that are sent by REC BMS websocket and parsed by the home assistant integration are below

Status

{"type":"status","bms_array":{"master":{"time_remaining":"Full in:<br> 31h 00 min","st_naprav":1,"time":"","date":"28.09.2025","mincell":3.304808,"maxcell":3.319811,"ibat":7.456289,"tmax":22.5,"vbat":13.2439,"soc":0.285054,"soh":0.9963,"erro":{"present":0,"addr":0,"st":0,"con_st":0},"error":""},"slave":{"0":{"address":2,"st_temp":1,"temp_bms":28.66577,"st_celic":4,"temp":{"0":22.5},"res":{"0":0.00195,"1":0.003093,"2":0.002179,"3":0.001809},"nap":{"0":3.304808,"1":3.319811,"2":3.310808,"3":3.308474},"bal":{"0":true,"1":false,"2":false,"3":false}}}}}

Settings

{"type":"settings","cmin":3,"cmax":3.65,"tmax":55,"bvol":3.58,"bmin":3.45,"tbal":55,"tmin":-10,"capa":320,"char":3.58,"ioff":0,"chis":0.25,"razl":0.25,"maxh":0.25,"minh":0.1,"bmth":2,"ioja":0.019531,"soch":0.05,"op2l":3.55,"op2h":0.15,"re1h":0.15,"chac":0.5,"dchc":0.5,"maxc":150,"maxd":150,"clow":3.1,"socs":0.284956,"cycl":37,"cans":2,"chem":3,"strn":2,"re1t":1979711486,"op2t":380239933,"re1v":3.30481,"op2v":3.31648,"cfvc":0.1,"rsbr":2,"err":{"p":0,"num":0},"nnc":{"bms":2,"cell":1},"vnc":{"bms":2,"cell":2},"toor":{"bms":2,"cell":1},"baud":{"lcd":56000,"com":115200},"mcu_date":"28.09.2025","bms_name":"1A-2261","addr":64,"tunit":0,"Ah":227,"cur":7.20264,"new_log_every_midnight":true,"out":false}

Support

You have issue with the integration? Please open an Issue.