Home Assistant Blueprint: Low battery level detection & notification for all battery sensors

low_battery.yaml

blueprint:
  name: Low battery detection (using state.name)
  description: >
    Checks battery sensors daily at a specified time on selected days.
    Numeric sensors below a threshold or binary sensors with state='on'
    are considered low. Excludes specified devices/areas/entities.
    Calls a user-specified notify service with a custom message, and
    uses state.name if available (just like your Dev Tools test), 
    falling back to entity_id if needed.
  domain: automation

  input:
    threshold:
      name: Battery Warning Level Threshold
      description: >
        Numeric sensors below this % are considered low.  
        Binary sensors with device_class=battery and state='on'
        are also considered low regardless of threshold.
      default: 70
      selector:
        number:
          min: 5
          max: 100
          unit_of_measurement: "%"
          mode: slider
          step: 5

    time:
      name: Time to Run
      description: "Runs at this time on the selected days."
      default: "10:00:00"
      selector:
        time: {}

    days_of_week:
      name: Days to Run
      description: >
        Select one or more days to run. By default, it runs Monday–Sunday.
      default:
        - Monday
        - Tuesday
        - Wednesday
        - Thursday
        - Friday
        - Saturday
        - Sunday
      selector:
        select:
          mode: list
          multiple: true
          custom_value: false
          options:
            - Monday
            - Tuesday
            - Wednesday
            - Thursday
            - Friday
            - Saturday
            - Sunday

    exclude:
      name: Excluded Battery Sensors
      description: >
        Exclude devices, areas, or entities with device_class=battery
        you do NOT want reported as low battery.
      default: { entity_id: [] }
      selector:
        target:
          entity:
            device_class: battery

    notify_service:
      name: Notification Service
      description: >
        Enter the notify service (e.g. notify.mobile_app_iphone). 
        By default, "notify.all_devices" if you have a group configured.
      default: "notify.all_devices"
      selector:
        text: {}

    notification_title:
      name: Notification Title
      description: >
        Title for the notification (some platforms ignore titles).
      default: "Low Battery Warning"
      selector:
        text: {}

    notification_message:
      name: Notification Message
      description: >
        Body of the notification. Use `{{ sensors }}` to show the list  
        of low-battery sensors. For example:  
        "Low battery on: {{ sensors }}"
      default: "Low battery on: {{ sensors }}"
      selector:
        text: {}

  # You can link to your GitHub or docs here if you wish.
  source_url: https://gist.github.com/youruser/low-battery-state-name.yaml

variables:
  threshold: !input "threshold"
  days_of_week: !input "days_of_week"
  exclude: !input "exclude"
  notify_service: !input "notify_service"
  notification_title: !input "notification_title"
  notification_message: !input "notification_message"

  # Flatten multi-level excludes (device, area, entity, label)
  exclude_entities: >
    {%- set ns = namespace(ret=[]) %}
    {%- for key in ['device', 'area', 'entity', 'label'] %}
      {%- set items = exclude.get(key ~ '_id', []) %}
      {%- if items %}
        {%- set items = [items] if items is string else items %}
        {%- if key == 'entity' %}
          {# Already entity_ids #}
          {%- set ns.ret = ns.ret + items %}
        {%- else %}
          {# Convert device/area/label to entity_ids #}
          {%- set more = items | map(key ~ '_entities') | sum(start=[]) %}
          {%- set ns.ret = ns.ret + more %}
        {%- endif %}
      {%- endif %}
    {%- endfor %}
    {{ ns.ret | sum(start=[]) }}

  sensors: >-
    {%- set result = namespace(sensors=[]) -%}

    {# 1) Numeric battery sensors #}
    {% for state in states.sensor %}
      {% if state.attributes.device_class == 'battery'
         and (state.entity_id not in exclude_entities) %}

        {# Try numeric from state, or fallback to .battery / .battery_level #}
        {% set numeric_battery = none %}
        {% if (state.state|float(-1) >= 0) and (state.state|float(-1) <= 100) %}
          {% set numeric_battery = state.state|float(0) %}
        {% elif state.attributes.battery is defined
               and (state.attributes.battery|float(-1) >= 0)
               and (state.attributes.battery|float(-1) <= 100) %}
          {% set numeric_battery = state.attributes.battery|float(0) %}
        {% elif state.attributes.battery_level is defined
               and (state.attributes.battery_level|float(-1) >= 0)
               and (state.attributes.battery_level|float(-1) <= 100) %}
          {% set numeric_battery = state.attributes.battery_level|float(0) %}
        {% endif %}

        {% if numeric_battery is not none and numeric_battery < threshold %}
          {# Use state.name exactly like your Dev Tools snippet #}
          {% set sensor_name = state.name | default(state.entity_id) %}
          {% set result.sensors = result.sensors + [
            sensor_name ~ ' (' ~ numeric_battery|string ~ '%)'
          ] %}
        {% endif %}
      {% endif %}
    {% endfor %}

    {# 2) Binary battery sensors #}
    {% for state in states.binary_sensor %}
      {% if state.attributes.device_class == 'battery'
         and (state.entity_id not in exclude_entities)
         and state.state == 'on' %}
        {% set sensor_name = state.name | default(state.entity_id) %}
        {% set result.sensors = result.sensors + [sensor_name] %}
      {% endif %}
    {% endfor %}

    {{ result.sensors | unique | sort | join(', ') }}

trigger:
  - platform: time
    at: !input "time"

condition:
  - condition: template
    value_template: >
      {{
        sensors != '' and
        now().strftime('%A') in days_of_week
      }}

action:
  - service: "{{ notify_service }}"
    data:
      title: "{{ notification_title }}"
      message: "{{ notification_message }}"

mode: single