Home Assistant Blueprint: Low Battery Notificator

low_battery_notificator.yaml

blueprint:
  name: Low Battery Notificator
  description: Notifies when any battery sensor drops below a defined threshold, excluding selected devices. Executes periodically and at defined times, with optional logging.
  domain: automation
  author: Edison Montes @_GeekMD_
  homeassistant:
    min_version: 2024.6.0

  input:
    start_time:
      name: Start Time
      description: Start of the notification window.
      default: '08:00:00'
      selector:
        time: {}

    end_time:
      name: End Time
      description: End of the notification window.
      default: '22:00:00'
      selector:
        time: {}

    battery_level:
      name: Battery Level Threshold
      description: Notify when battery is below this percentage.
      default: 20
      selector:
        number:
          min: 0
          max: 100
          step: 1
          unit_of_measurement: '%'
          mode: slider

    interval_minutes:
      name: Execution Interval (Minutes)
      description: Run every N minutes during the time window.
      default: 30
      selector:
        number:
          min: 1
          max: 120
          step: 1
          unit_of_measurement: min

    excluded_devices:
      name: Excluded Devices
      description: Battery sensors to exclude from monitoring.
      default: []
      selector:
        entity:
          multiple: true
          domain: sensor
          device_class: battery

    enable_logging:
      name: Enable Logging
      description: Show a persistent notification every time low battery is detected.
      default: false
      selector:
        boolean: {}

    actions:
      name: Actions
      description: >
        Actions to run when low battery is detected.

        Use `{{ low_battery_list | join('\n') }}` in your message to list devices.
      selector:
        action: {}

trigger:
  - platform: time
    at: !input start_time
  - platform: time
    at: !input end_time
  - platform: homeassistant
    event: start
  - platform: template
    value_template: >
      {% set minutes = now().minute %}
      {% set interval = interval_minutes | int %}
      {{ (minutes % interval) == 0 }}

variables:
  battery_level: !input battery_level
  interval_minutes: !input interval_minutes
  enable_logging: !input enable_logging
  excluded_devices: !input excluded_devices
  excluded_ids: "{{ excluded_devices | map(attribute='entity_id') | list }}"
  low_battery_devices: >
    {% set umbral = battery_level | int %}
    {% set baterias_bajas = namespace(lista=[]) %}

    {% for entidad in states.sensor
        if entidad.attributes.device_class == 'battery' and entidad.entity_id not in excluded_ids %}

      {% set estado = entidad.state %}
      {% set nivel = estado | int(default=100) %}

      {% if estado not in ['unknown', 'unavailable', 'none']
            and nivel >= 0
            and nivel < umbral %}

        {% set nombre = entidad.attributes.friendly_name %}
        {% set linea = nombre ~ ' (' ~ nivel ~ '%)' %}
        {% set baterias_bajas.lista = baterias_bajas.lista + [linea] %}
      {% endif %}
    {% endfor %}

    {{ baterias_bajas.lista }}

condition:
  - condition: and
    conditions:
      - condition: time
        after: !input start_time
        before: !input end_time
      - condition: template
        value_template: "{{ low_battery_devices | length > 0 }}"

action:
  - variables:
      low_battery_list: "{{ low_battery_devices }}"
  - choose:
      - conditions:
          - "{{ low_battery_devices | length > 0 }}"
        sequence:
          - choose: []
            default: !input actions
          - service: logbook.log
            data:
              name: Low Battery Notificator
              message: >
                Executed at {{ now().strftime('%Y-%m-%d %H:%M:%S') }}.
                Devices below {{ battery_level }}%: {{ low_battery_devices | length }}
      - conditions:
          - "{{ low_battery_devices | length == 0 }}"
        sequence:
          - service: logbook.log
            data:
              name: Low Battery Notificator
              message: >
                Automation executed at {{ now().strftime('%Y-%m-%d %H:%M:%S') }}.
                No devices below threshold — no action taken.
  - choose:
      - conditions:
          - "{{ enable_logging }}"
        sequence:
          - service: persistent_notification.create
            data:
              title: "Low Battery Check Executed"
              message: >
                Execution time: {{ now().strftime('%Y-%m-%d %H:%M:%S') }}
                Interval: every {{ interval_minutes }} minutes
                Devices below threshold: {{ low_battery_devices | length }}
                {% if low_battery_devices | length > 0 %}
                {{ low_battery_devices | join('\n') }}
                {% else %}
                No devices with low battery.
                {% endif %}

mode: single