Unknown sensor calculation causing error

Configuration
1

I have a value template that seems to be causing me some problems when one of the sensors is ‘unknown’.

value_template: '{{ ((states("sensor.torana_available_charging_current")|float + states("sensor.torana_tesla_watts")|float)/(states("sensor.grid_voltage")|float) - 2|float)|round(0) }}'

I know that sensor.torana_tesla_watts is going to be unknown when it isn’t powered on so how do effectively treat this? I expect somehow I need to tell the value_template that when unknown make it zero or another way. What is the best way to do this?

I notice this within home_assistant.log

2021-11-20 09:40:17 WARNING (MainThread) [homeassistant.helpers.template] Template warning: 'float' got invalid input 'unknown' when rendering template '{{ ((states("sensor.torana_available_charging_current")|float + states("sensor.torana_tesla_watts")|float)/(states("sensor.grid_voltage")|float) - 2|float)|round(0) }}' but no default was specified. Currently 'float' will return '0', however this template will fail to render in Home Assistant core 2022.1

2

First, you need to supply each instance of float with a default value. I have chosen 0 but you can select whatever value you think is appropriate.

value_template: '{{ ((states("sensor.torana_available_charging_current")|float(0) + states("sensor.torana_tesla_watts")|float(0))/(states("sensor.grid_voltage")|float;0)) - 2|float;0))|round(0) }}'

Second, you should enhance your Template Sensor’s configuration with an availability_template. Minimally, I suggest this because you said “I know that sensor.torana_tesla_watts is going to be unknown when it isn’t powered on”.

availability_template: '{{ states("sensor.torana_tesla_watts") not in ["unavailable", "unknown"] }}'

If the state value of sensor.torana_tesla_watts is either unavailable or unknown, the template reports false. As a result, the value_template is not evaluated.