Since most 220v devices are going to pull the same amount of current from both sides of the 110. It would be awesome if one could just attach the probe to one line on the 220v breaker and tell the app to just double the value. That way you could potentially monitor 2 separate 220 lines. It’s not going to be as accurate I’m sure, but I’d be willing to sacrifice accuracy for multiple monitoring.
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@coryhillmann ,
Good observation. That’s exactly how the Sense Flex Sensors can be used to do Dedicated Circuit Monitoring (DCM). The two CTs can be used in 2x240, 1x240/1x120 or 2x120 configurations. All possible if you don’t need the second CTs for Solar.
If you have Solar like me, then you can use a second Sense monitor on a second account to watch at least 2, if not 3 circuits if you are clever, then feed the data back into your main Sense via Home Assistant.
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What would be even cooler… Say you have 2 sense meters and 4 sets of CT’s. 1 set on the Mains… Set on solar, the other 2 sets on your dedicated circuits and it all show up like 1 Sense meter. Should be total do able.
This configuration would even be do able if you had a sub panel… This should be even an easier integration than kasa/ TP-link or wemo.
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I would lover that too - maybe @coryhillmann would allow me to change the title a little to represent what you are asking for, since Sense already allow the Multiple 220/240V monitoring if you have the second ports available.
I can see three barriers to what you suggest, if you include cost:
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Sense Setup for Mains CTs - The setup process has two interrelated issues that reduce current usability. Sense tries to combine the current / power for both, and therefore does a polarity / phase consistency check to make sure it is seeing two supplies that are the same polarity and opposite phase. You can get by this step by initially placing the CTs on your mains and then transferring them later. But Sense is still hardwired to combine the two so if you move the CTs to measure single legs of two different 240V circuits, you’ll need to make sure you are measuring opposite phases / legs and you don’t flip polarities, and even then you’ll only see both circuits combined in the Total Usage category, that you can’t rename. Of course the bubbles will be meaningless as well (especially Other and Always On), except for the bubbles coming from the second set of CTs operating in DCM mode. The alternate strategy that I would recommend is to try the mains of the second “DCM Monitor” on any unbalanced 240V loads you have in your house. Just turn the device on and go through the normal Sense setup process. You shouldn’t have any issues if you are monitoring both phases of singe 240V device, plus Sense’s built-in combining fits naturally.
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Combining Data from Two Monitors and Accounts - There’s no direct way for your Main Sense monitor to incorporate the device data from the second monitor that is collecting up to 4 240V measurements (1 or 2 combined in Total Usage, plus 2 from the DCM CTs). To see usage combined, I would do two steps: 1) connect both your Senses to Home Assistant and combine there to double check, then 2) use SenseLink from Home Assistant to pipe the data (entities) from the second monitor back to the main Sense monitor.
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Cost - Pretty expensive for 3-4 extra measurements. But Sense can’t do much about that without a whole different hardware scheme. The Sense monitor is fairly expensive to build because it uses some pricey chips inside that allow it to do the high speed sampling, plus so some realtime DSP (digital signal processing). @Ingo was just inside of his monitor so maybe he could commented on estimate BOM (bill of materials) cost. I’m guessing the onboard main processor/DSP and Altera CPLD are fairly expensive.
Not sure if the link below comes through or not. If not search for “Sense Energy monitor teardown”. That article gives you a good idea of what’s inside a Sense Monitor. This one shows an earlier revision but the main components are the same. I haven’t looked at a detailed BOM but I can tell you that with chip prices through the roof the BOM is certainly not a cheap one nowadays
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