Solar radiation from Solar Panels?

[Taraman17]

Hi,
since I don't have any sensor for measuring solar radiation, I was just wondering if there might be a way to derive that from my PV-data?

[jeroenterheerdt]

sorry, what is PV?

[cryptedx]

He is meaning Photovoltaik = Solar

[jeroenterheerdt]

ah thanks - I am not sure how that would work, I guess you can somehow take the values from your PV system and convert them to solar radiation, but I don't know how and it's probably dependent on your PV system.

[cryptedx]

Thank you for your great question. I also ask that to me some days ago but did not had the motivation to figure it out by myself. Now I tried it with ChatGPT and it brought me to this solution:

sensor:
  - platform: template
    sensors:
      garage_solar_irradiance:
        friendly_name: "Garage Solar Irradiance"
        unit_of_measurement: "W/m²"
        value_template: >
          {% set pv_power_output = states('sensor.sunny_tripower_x_25_pv_power_c') | float %}
          {% set panel_area = 25.5 %} 
          {% set panel_efficiency = 0.22 %} 
          {% if panel_area > 0 and panel_efficiency > 0 %}
            {{ (pv_power_output / (panel_area * panel_efficiency)) | round(2) }}
          {% else %}
            0
          {% endif %}

I have set it up but it's dark now. Let's see how it will perform tomorrow.

[Taraman17]

That sounds like a good starting point.
I will experiment with that the next days.

[cryptedx]

It looks like to be working for me. Now let's see what irrigation values I will get in the next days.

[Taraman17]

So, the sensor is working.
I wonder if that if-statement in the template is really needed, since the variables are set statically and will never be 0, so the if statement will always be true.

I will see, what irrigation values I get from this and then tweak it to my needs.
Since I have a very cluttered irrigation system, in which I have to estimate the values anyway, I will change it so, the values make sense to me and use these.