Battery low warning home assistant blueprint

battery_low_mobile_notification.yaml

blueprint:
  name: Low battery level detection & notification for all battery sensors
  description: Regularly test all sensors with 'battery' device-class for crossing
    a certain battery level threshold and if so execute an action.
  domain: automation
  input:
    threshold:
      name: Battery warning level threshold
      description: Battery sensors below threshold are assumed to be low-battery.
      default: 20
      selector:
        number:
          min: 5.0
          max: 100.0
          unit_of_measurement: '%'
          mode: slider
          step: 5.0
    time:
      name: Time to test on
      description: Test is run at configured time
      default: '10:00:00'
      selector:
        time: {}
    day:
      name: Weekday to test on
      description: 'Test is run at configured time either everyday (0) or on a given
        weekday (1: Monday ... 7: Sunday)'
      default: 6
      selector:
        number:
          min: 0.0
          max: 7.0
          mode: slider
          step: 1.0
    notify_device:
      name: Device to notify
      description: Device needs to run the official Home Assistant app to receive notifications
      selector:
        device:
          integration: mobile_app
variables:
  day: !input 'day'
  threshold: !input 'threshold'
  counttotal: >-
    {% set data = namespace(battery_list=[]) %}
    {% for batt in states.sensor | selectattr('attributes.device_class','eq','battery') -%}  
      {% set data.battery_list = data.battery_list + [{'name': batt.attributes.friendly_name, 'level_int': batt.state|int(0), 'level_str': batt.state}] %}
    {%- endfor %}
    {{ data.battery_list | count }}  
  countlow: >-
    {% set data = namespace(battery_list=[]) %}
    {% for batt in states.sensor | selectattr('attributes.device_class','eq','battery') -%}  
      {% set data.battery_list = data.battery_list + [{'name': batt.attributes.friendly_name, 'level_int': batt.state|int(0), 'level_str': batt.state}] %}
    {%- endfor %}
    {{ data.battery_list 
      | selectattr('level_int', 'lessthan', threshold) 
      | list 
      | count }}    
  listtextlow: >-
    {% set data = namespace(battery_list=[]) %}
    {% for batt in states.sensor | selectattr('attributes.device_class','eq','battery') -%}  
      {% set data.battery_list = data.battery_list + [{'name': batt.attributes.friendly_name, 'level_int': batt.state|int(0), 'level_str': batt.state}] %}
    {%- endfor %}
    {% for batt in data.battery_list 
      | sort(attribute='level_int')
      | selectattr('level_int', 'lessthan', threshold) 
      %} 
      {{ batt.name }} is {% if batt.level_int != 0 -%} 
        {{ batt.level_int }}%
      {%- else -%}
        {{ batt.level_str }} 
      {%- endif -%}
    {%- endfor %}   
  notification_message: "{% if countlow > 0 -%}{{countlow}} out of \
{{ counttotal }} device batteries are low:

{{listtextlow}}
{%- else -%}
All {{counttotal}} device batteries are ok!
{% endif %}"
trigger:
- platform: time
  at: !input 'time'
condition:
- condition: template
  value_template: '{{ sensors != '''' and (day | int == 0 or day | int == now().isoweekday())
    }}'
action:
- device_id: !input 'notify_device'
  domain: mobile_app
  type: notify
  title: 'Battery Check'
  message: '{{ notification_message }}'
- service: persistent_notification.create
  data:
    title: 'Battery Check'
    message: '{{ notification_message }}'
    notification_id: battery-check

For anyone else just finding this, I don't think it works any more. Devices all report as being fine even if they fall below the threshold you set.

Hi All, been a long time since I touched this. Yes, I found a problem recently as well. I think the entity_id attribute got removed from one of the structures I was using.
Also @Erickclee there were some shortcuts being taken here for sure - e.g. the list was being sorted by string version of battery percentage, meaning silly sort orders like 0, 1, 100, 12, 3, 50, 9. I've fixed that now.

Also, important: I've made it handle unavailable sensors now, which was a niggle all along. Previously, once a battery got so low it went offline, it disappeared from the list. Now it shows at the top of the list.

The end result for me and I expect many others, is that this blueprint will now show you a whole load of long since forgotten devices, and probably some devices reporting batteries that don't even have them. That prompted me to remove lots of old devices from my setup and 'un enable' bogus battery sensors in the config. Please re-import and comment back here if you have any further issues.

Thanks!