CTs that are smaller than 50A

[waterboyz]

I’m wondering if there is a plan for smaller amp CTs?

As Jim says below, the 50A CTs will have difficulty (maybe not the best word) in measuring below 20 watts.  I’ve read elsewhere that the sweet spot for accuracy of CTs is in their mid-range.  Since a lot of circuits that we are monitoring are 15 and 20 amp service it would seem that a lower-rated CT would be more accurate.

Jim wrote this on 11/14/2019

“What are the limits of the Emporia sensors?
Our sensors have physical limitations. Each 200A sensor is accurate with high resolution between 2A – 250A (240W – 30kW @ 120V). And each 50A sensor is accurate with high resolution between 0.17A – 63A (20W – 7500W). When you go below those ranges, the 200A sensors will report about 100-150W of noise and the 50A sensors will report about 10-20W of noise. However, when in range, the sensors can resolve differences as low as a handful of watts. The app filters out this noise so you’ll see no load when the sensors are below the threshold of 20 watts for 50A sensors and 90 watts for our 200A sensors. However, if you download the raw data, you will see the reported noise – giving a slight discrepancy between the app and the raw data.”

[jj613]

Why do you want to monitor this?   (I don’t mean that critically, i’m genuinely interested in why.)

It seems like the Vue app and the whole system is focused on long term energy consumption.   The second and minute views are incomplete and importantly they can’t be used to manage total instantaneous power consumption.   I think the Vue system with some small improvements COULD do that quite well but not as it works now.

Since it’s mainly about energy consumption over time, an entire circuit using 20W would contribute a negligible amount.  So before they build smaller CTs I’d like to see them update their software to include functions that would make that useful.  I’d love to see subsecond samples, and I’d love to see second and subsecond data stored for longer.

[waterboyz]

jj613 said:

Why do you want to monitor this?   (I don’t mean that critically, i’m genuinely interested in why.)

It seems like the Vue app and the whole system is focused on long term energy consumption.   The second and minute views are incomplete and importantly they can’t be used to manage total instantaneous power consumption.   I think the Vue system with some small improvements COULD do that quite well but not as it works now.

Since it’s mainly about energy consumption over time, an entire circuit using 20W would contribute a negligible amount.  So before they build smaller CTs I’d like to see them update their software to include functions that would make that useful.  I’d love to see subsecond samples, and I’d love to see second and subsecond data stored for longer.

No offense was taken.

I was mainly trying to say that having smaller CTs would/could be more accurate for the most usually monitor circuits.  Yes, 20w is tiny in the overall scheme since that is what was quoted.  I’m guessing that there are/will be people who are using this device for charging people for their usage.  I’m not in that situation.

I mainly want to find out why my neighbor has a lower electric bill than me.  Plus I will be installing a generator soon so usage would be very useful for that.  I have a relative with a house that has 1000+ more square feet than mine and is paying less per month.  I know, there are lots of variables to consider but on the surface…….

[jj613]

@waterboyz I mustn’t come between you and your neighbor. Maybe it’s your Jacuzzi?   🙂 🙂

I would however love to discuss ideas around Vue+Generator.   I bought the Vue half for energy monitoring and half for generator power monitoring.  I’ve discovered that it is of some use for the latter (better than Sense) but with some severe limitations.

Maybe start a new question for this?

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