Calculation (Subtraction) of 2 Sensors

[bosx2 (Marc)]

Hello, I´m going crazy, since I am unable to calculate (substract) 2 Sensors for a Solar Device.

I have 2 main sensors I need to use:
sensor.ess_ess_home_statistics_pcs_pv_total (current solar power in W)
sensor.ess_ess_common_load_load_power (current total power consumption in W)

My goal is to get two custom sensors:

1. Sensor
   feed grid in calculation:
   sensor.ess_ess_home_statistics_pcs_pv_total - sensor.ess_ess_common_load_load_power = “feed grid in power total”

2. Sensor
   grid consumptions calculation:
   sensor.ess_ess_common_load_load_power -sensor.ess_ess_home_statistics_pcs_pv_total - = “grid consumption power total”

I tried

template:
  - sensor:
      - name: "VattenfallVerbrauch"
        unit_of_measurement: "W"
        state: "{{ states('sensor.ess_ess_common_load_load_power')|float(0) - states('sensor.ess_ess_home_statistics_pcs_pv_total')|float(0) }}"

but I dont get a new sensor or any value, I´m stuck , can someone explain what I´m doing wrong?

[Stiltjack]

How to format your code in forum posts

Spaces at the beginning of the line are critical in yaml, and people trying to help you may want to copy your code so that they can try it out themselves, so please format it correctly when you are posting. Use the preformatted text tool (</> in the edit post toolbar). If it is not immediately visible, it will be in the cogwheel menu. [Code_format] Alternatively you can use three backticks (the key is on the far left, 2nd row on en keyboards) on their own line above and below the code. That i…

[francisp (Francis)]

Sensor looks good, but if it is your first template sensor, you need to restart HA.

[Troon]

You can create this in the UI, under Helpers. Paste in the template {{ ... }} that you already have into the State Template box.

[bosx2 (Marc)]

now I think I´m stupid… man, thanks… I only did a soft restart, but it appears after a full restart

thanks!

[bosx2 (Marc)]

what settings in the UI I can use, to substract? I only found summary as calculation

[ThomDietrich]

Hey @bosx2,
depending on your system and setup you might experience another issue. As both sensors are from your ESS, probably not an actual problem. Just so you are aware.

The way you have set it up now, your template sensor will update when either the load_power changes, or when the pv_total changes. You might run into the issue in which for a brief second one value will have changed significantly, while the other one reacts to that a second later. You might end up seeing spikes in your resulting sensors when e.g. a cloud moves in front of your PV or when you turn on your washing machine. So look out for that.

Btw you should think about your device and entity names. The ones I am seeing are horrible

[francisp (Francis)]

This one, where you could paste

{{ states('sensor.ess_ess_common_load_load_power')|float(0) - states('sensor.ess_ess_home_statistics_pcs_pv_total')|float(0) }}

in state template

[bosx2 (Marc)]

wow! I am baffled by the support by this community. Thank you so much