One smart plug is a "child" of another... how to count (or not double count) this?

I’ve built myself a large-ish UPS from a couple of surplus LiFePo4 batteries and an inverter/charger of th etype often found in RVs/campers. At present, I have a set of Kasa/TP-Link smart plugs scattered across the house, and in particular I have one of them at the plug between the wall and the UPS/inverter and another at the inverter’s output plug.

This setup allows me to do a few things:

  1. turn off the load on the inverter in case I need to
  2. turn off the input supply to the inverter, which allows me to manually test and/or cycle the battery system itself
  3. compute the efficiency of the inverter - if I can measure watts and watts out, I know what’s getting wasted inside the inverter/charger.

Anyway, that’s somewhat contextual and not my actual question :wink:

In this setup, if plug1 is between the wall and the inverter and plug2 is the output of the inverter, Sense sees both of these devices as on and connected, but it does NOT have any way to know that the watts from plug2 have already been counted (by plug1). This means that I’ve got anywhere from a few dozen to several hundred watts of power that’s being counted incorrectly and (presumably) throwing off lots of other computations.

Any suggestions as to how I might mitigate this?

Not sure there is a clean way to do it if you want Sense to measure both as devices. The special “What’s connected to this ?” setting to avoid double counting only works for one or more Sense AI detected devices, not other smart plugs. If you can live with only one reading via Sense and another via the Kasa app or via Home Assistant, you could banish the second smart plug to a different WiFi SSID that isn’t on the same subnet as the one you use for your Sense (or other networking ways of preventing broadcasts from the Sense monitor getting to that second smart plug). That will prevent one of them from showing up in your Sense.

The only computation affected is the magnitude of Other. I have lots of native devices behind smart plugs that I do not link, and don’t see any issues except that Other is often missing (Sense hides the other bubble if it would have a negative value). Read more about my results in the post linked below.

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