The following warning appears (many times) under 2021.10, and says that the template will no longer work under 2021.12:
Template warning: 'float' got invalid input 'Not Charging' when rendering template '{% macro battery_level() %} {% for entity_id in states.group.battery_status.attributes.entity_id if ( not is_state_attr(entity_id, 'battery_alert_disabled', true) and states(entity_id) is not none and ( ( ( states(entity_id) is number or states(entity_id) | length == states(entity_id)| int | string | length or states(entity_id) | length == states(entity_id)| float | string | length ) and states(entity_id) | int < states.input_number.battery_alert_threshold_max.state | int and states(entity_id) | int > states.input_number.battery_alert_threshold_min.state | int ) or states(entity_id) | lower == 'low' or states(entity_id) | lower == 'unknown' or states(entity_id) | lower == 'unavailable' ) ) -%} {{ state_attr(entity_id, "friendly_name") }} ({{ states(entity_id) }}) {% endfor -%} {% endmacro %} {{ battery_level() | trim == "" }}' but no default was specified. Currently 'float' will return '0', however this template will fail to render in Home Assistant core 2021.12
The following warning appears (many times) under 2021.10, and says that the template will no longer work under 2021.12: