Dedicated Circuit Monitoring (DCM) if you already have Sense Solar?

Several Sense Solar users, including @andy, have raised the question fo how they might take advantage of DCM, since their second monitor port is already occupied with solar monitoring. I have done a little experimenting and been able to test an approach for Solar users, by using a second Sense monitor for its DCM capacity. I currently have 2 x 240V devices monitored by my new Sense, a Tesla charger and sub panel for all my floor heating coils. A few caveats upfront:

  • Pricey - you have to buy a second Sense monitor and a set of Flex cables. But for me, this was still way cheaper and easier than a CT per circuit approach.
  • Requires a second account and blending data between two accounts - Most of of my data comes from my main Sense, but when I want to sum up usage by all devices, I have to resort to data export and spreadsheet or R.
  • Setup was a little tricky - Setting up a second monitor without the second port on my solar backfeed gave problems during the initial setup. Sense support helped me get through setup. I should also comment that this is not an officially supported configuration.

Here’s what I had to do:

  • Buy second Sense monitor and Flex cable
  • Install the Sense, with the mains CTs on my mains, and the secondary (middle port) CTs installed on a single hot line of my two BALANCED (no neutral connection) 240V device.
  • Run setup on the Sense, by creating a second account. For me, the setup process got stuck, then support eventually pushed it through, but it jumped to a Solar configuration, even though my second set of CTs weren’t on a solar backfeed. I suspect that Sense sees negative power on my mains (solar producing are than I am using) and automatically trips to solar.
  • Ask Sense support to disable the Solar so I could go through the DCM setup process. They did.
  • Execute DCM setup - for both devices, I couldn’t use the breakers to turn the devices on. I had to use the thermostat to start a floor loop and had to manually start the charging process for the EV. But in the end, setup worked !

I now have two 240V DCM devices registering on my second Sense account.

BTW, the second benefit of my second is that I placed it on my main network, vs. my IoT network, where all my other Sense / smart-plug stuff lives, which means that I can also see my Hue devices. My IoT network isn’t wired, so the the Hue can’t report to my main Sense on that network.

So I can now see details of both my charging

and my floor heating.

https://community.sense.com/t/nuheat-heating-coils-with-nuvent-thermostats/12651/2

ps: I suppose, if I were very careful with polarities and L1/L2, I could move my second Sense’s mains CTs to another balanced or unbalanced 240V circuit for monitoring. I would have to treat the Power Meter and Total Consumption as my third device, since it wouldn’t show up directly in devices. Gonna have to try sometime. That would give me 3 240V devices out of my second Sense.

1 Like

A second Sense is outrageously more costly for only two more 240v circuits, compared to what two HS110 like monitors should have cost…and it can not handle the other half dozen 240v devices many of us have.

I’ll pass on this idea, thanks.

| kevin1 Volunteer Moderator
November 14 |

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Several Sense Solar users, including @andy, have raised the question fo how they might take advantage of DCM, since their second monitor port is already occupied with solar monitoring. I have done a little experimenting and been able to test an approach for Solar users, by using a second Sense monitor for its DCM capacity. I currently have 2 x 240V devices monitored by my new Sense, a Tesla charger and sub panel for all my floor heating coils. A few caveats upfront:

  • Pricey - you have to buy a second Sense monitor and a set of Flex cables. But for me, this was still way cheaper and easier than a CT per circuit approach.
  • Requires a second account and blending data between two accounts - Most of of my data comes from my main Sense, but when I want to sum up usage by all devices, I have to resort to data export and spreadsheet or R.
  • Setup was a little tricky - Setting up a second monitor without the second port on my solar backfeed gave problems during the initial setup. Sense support helped me get through setup. I should also comment that this is not an officially supported configuration.

Here’s what I had to do:

  • Buy second Sense monitor and Flex cable
  • Install the Sense, with the mains CTs on my mains, and the secondary (middle port) CTs installed on a single hot line of my two BALANCED (no neutral connection) 240V device.
  • Run setup on the Sense, by creating a second account. For me, the setup process got stuck, then support eventually pushed it through, but it jumped to a Solar configuration, even though my second set of CTs weren’t on a solar backfeed. I suspect that Sense sees negative power on my mains (solar producing are than I am using) and automatically trips to solar.
  • Ask Sense support to disable the Solar so I could go through the DCM setup process. They did.
  • Execute DCM setup - for both devices, I couldn’t use the breakers to turn the devices on. I had to use the thermostat to start a floor loop and had to manually start the charging process for the EV. But in the end, setup worked !

I now have two 240V DCM devices registering on my second Sense account.

BTW, the second benefit of my second is that I placed it on my main network, vs. my IoT network, where all my other Sense / smart-plug stuff lives, which means that I can also see my Hue devices. My IoT network isn’t wired, so the the Hue can’t report to my main Sense on that network.

So I can now see details of both my charging

Tesla Model 3 Long Range - HPWC Community Device Library

Make: Tesla Model: Model 3 Long Range How identified: Sense Dedicated Circuit Monitor (DCM) Power Specs: Car charging on HPWC at 48A limit. 11,494W (per Sense) / 240V = 47.89A, so good correlation. Detailed View: The initial charging ramp. Seems to change with each Tesla SW update. My car is set to start charring at 3:30AM [IMG_0339.PNG] Looks like charging took a break in the middle and then ramped again ?? [IMG_0340.PNG] Power drops much more quickly at the end of the charge cycl…

and my floor heating.

https://community.sense.com/t/nuheat-heating-coils-with-nuvent-thermostats/12651/2

Definitely pricey but but less so than the CT per circuit approach. I really only have 3 challenging 240V devices (2 EV chargers and set of 5 floor coils). Sense has found the 2 AC compressors, ovens and dryer. I also have some 240V Fostoria outdoor heaters but they are used so infrequently. So a second Sense seems to be a workable solution for me.

One more note… It looks like Sense has put in a new check to watch for solar behavior without having a solar backfeed, so I’ll just have to ignore these occasional messages.