Inverter Self-Power consumption / efficiency

[hamgeezer]

How can I track my inverter power use? I use the Fox Modbus integration in Home Assistant and I'm trying to track down how much of my currently untracked usage is consumed by the inverter

[Dave Foster]

This can be a complex subject, one of my colleagues has done an excellent how does it work guide here and this cover all of the various possible losses that can occur in the system https://github.com/TonyM1958/HA-FoxESS- ... it-work%3F

If you have modbus this is the template sensor I have written that calculates system losses

Code: Select all

      - name: "System Losses"
        device_class: "power"
        unit_of_measurement: "kW"
        state: >
          {% set sl = ((states('sensor.pv1_power') | float(default=0)
                      + states('sensor.pv2_power') | float(default=0)
                      + states('sensor.grid_consumption') | float(default=0)
                      + states('sensor.battery_discharge') | float(default=0)
                      - states('sensor.battery_charge') | float(default=0)
                      - states('sensor.feed_in') | float(default=0)
                      - states('sensor.load_power')|float(default=0) )) | round(3) %}

and a riemann sum that converts that into energy (kWh)

Code: Select all

  - method: left
    name: losses_sum
    platform: integration
    round: 2
    source: sensor.system_losses
    unit_time: h

[hamgeezer]

Thank you! That's great for detecting losses in the system. Is there also a way of detecting how much the inverter itself uses? I assume this number is rolled up in the "Load Power" number, but I'd love to be able to track inverter consumption separately, much like I do with things like my fridge.

[Dave Foster]

That’s very difficult to isolate, system losses is the closest you will get to a sum of all losses in the inverter/batteries etc.. but to get to inverter consumption on it’s own not so easy.

When there is no solar it is effectively the difference between the battery discharge power and the load power, but as you could be charging or exporting you need to take into account feedin, grid consumption but that still only gives you the inverter use when it is running as a battery system so by the time you throw PV back into the mix you are at the system losses value.