Whole house power monitoring.

[shabba]

Hi,
I see some commercial offering that count meter ticks but are there any clamp style current meters that people have used to measure power usage in a house?

Thanks!

[gohan]

Of course there are, you could also make one out of an Arduino Uno one clamp an a small transformer, it depends if you want to go DIY or go with commercial product

[shabba]

DIY all the way! I assumed posting here would imply mysensors based but I guess I really should have been clear.

Thanks!

[dakipro]

Interested in the topic as well.
Also, would it be possible get the power for arduino from the clamp itself, wirelessly?
or you must have separate power source for arduino (I know this later is the case, but... you never know what smart people here can come up with)

[rozpruwacz]

lately I discovered EnOcean. They produce energy harvesting sensors for home automation. E.g. a batteryless push button It harvests energy from button presses - how cool is that They also have other energy harvesting technologies, but I don't think they would provide enough power for arduino board that measures the current and voltage continuously ...

[dakipro]

quick google search gave me this https://electronics.stackexchange.com/questions/189425/leach-circuit-to-power-microcontroller

[gohan]

@rozpruwacz Why would want energy harvesting on an energy meter that is actually measuring the mains? You can just use a power supply and you are fine. Anyway, if you want to go DIY look at openenergymonitor site on how to build the sensor

[rozpruwacz]

@gohan I don't know, I just pointed out that it may be possible

[gohan]

I have looked at enocean stuff some time ago, and it works similarly to zwave but with energy harvesting in mind. Btw since I brought up zwave... https://aeotec.com/z-wave-home-energy-measure

[shabba]

All I am looking for really is a sensor/circuit that I can hook up to a mini and mysensors network.

[gohan]

https://openenergymonitor.org/forum-archive/node/58.html then you add the mysensors code for communication.

[shabba]

@gohan Thank you!

[dakipro]

@gohan said in Whole house power monitoring.:

Why would want energy harvesting on an energy meter that

I live in building where meter is in a common locker, thus no plugs nor power supplies.

[gohan]

@dakipro then you should probably have a breaker box in the apartment, so you could put it there instead

[Nca78]

@gohan said in Whole house power monitoring.:

@dakipro then you should probably have a breaker box in the apartment, so you could put it there instead

That's a good idea but it's a bit tight in there

[gohan]

@nca78 nobody said life is easy

[Tmaster]

I'm using an arduino pro mini with an W500 Ethernet module connected directly to router,and a clamp from ebay(100amps i think). arduino and w500 fits inside a small box and its inside main power box,clamped to the main wire from main eletric deferential . I have the (ATI) Telecomonication box at side of power box so its easy to connect to the router. i dont use transformer for volt read,just read Amps because my power its very stable at 230/235v and this is just for " power waste "control

on first moth that i build it i saved 30€/moth in power(i not a commercial advertisement ).i had the electric resistance from water solar heating panel (3000w) working during the night,useless because we don't need hot water in morning,only at end of the day. so now i have another arduino that handle the hot water if there is no enough sun during the day... ( arduino pro minifor the win!!! )

This is a screenshot from my emoncms page. like you see my wife its doing cakes and dinner,and the oven and induction plate eat a lot of power ![

[superczar]

@gohan said in Whole house power monitoring.:

https://openenergymonitor.org/forum-archive/node/58.html then you add the mysensors code for communication.

+1 to that
I have been using a single clamp sensor on my neutral at the power meter (SCT-030) hooked to an arduino/ESP8266
It's been working great close to 3 years now with an accuracy of +- 7%
I even use the readings to detect brown-outs and trigger devices to original state after power flips back to mains from the back-up (I live in an area where brown-outs , or power-cuts as we call them , are quite common)

[kimot]

+/-7% is good, because Domoticz has it own error -8% when energy consumption calculation is done by Domoticz.
When I send 660 W constantly a few hours, I obtain energy consumption 604 - 609 Wh in this interval :o(
They do not add last 5 min energy consumption in one hour interval ( Argument - because data arrived not at xx:00:00 but XX:00:05 )
Look at Domoticz forum about this bug, if interested.
Boys from Domoticz said - it is not important ....

[gohan]

@kimot yeah, 5 minutes intervals are not the best for that kind of statistics; you'd probably better look at influxDB for more accurate statistics

[Nca78]

@kimot thank you for that information. One more nail in Domoticz' coffin for me...

[zboblamont]

@gohan Agreed that the Domoticz 5 minute sample frequency is inadequate for any accurate measurement, there was talk on the forums that this was to change to accurate time based series for the next version of Domoticz, how true that was and when this might appear is unknown.

I wasn't aware of that flaw @kimot, quite a curiosity...

I was pointed to NodeRed previously as a mechanism to duplicate the data stream and accurately record time-based data from pulse meters while passing on the data to Domoticz, I just haven't waded into the thrills of NodeRed yet.

Agreed that clamp meters are easier to install, when I was looking into them, many specifications show an average range of accuracy, but also read elsewhere that this accuracy is not linear, and becomes in reality quite inaccurate at low currents, I cannot recall the error %age.

[Nca78]

@zboblamont said in Whole house power monitoring.:

Agreed that clamp meters are easier to install, when I was looking into them, many specifications show an average range of accuracy, but also read elsewhere that this accuracy is not linear, and becomes in reality quite inaccurate at low currents, I cannot recall the error %age.

But probably it's not a big issue if you have 30% or more (no idea of the real numbers) of inaccuracy at low current, as long as you're much closer at high current which make the bulk of your power consumption ?

[zboblamont]

@nca78 Possibly that would be one approach, but there are so many other effects on CTs as opposed to direct reading meters, proximity of adjacent cable, temperature, humidity, etc., all introducing errors on top of it's spec and how well it is QC'd at manufacture.

Industrial 50A clamps can work down to 0.125A with 2.5% error, the typical 100A domestic variety would not get close I suggest.

Don't misunderstand my comments, where it is impossible to install direct reading meters I see the necessity, just cautioning that they are by nature a compromise.

[gohan]

@zboblamont just for clarification, what do you mean by "direct reading "?

[zboblamont]

@gohan Sorry for any confusion, I meant in-line meters, where there is direct reading of voltage, current, pf, etc....

[gohan]

@zboblamont have you found any worth mentioning?

[zboblamont]

@gohan I guess you meant in-line meters? Not specific device recommendations, but more a methodology, none of which is new.

The supply here is about 65A, so perhaps not euro-typical, in the UK it would be a standard 100A supply even though full load current would rarely top 50A unless you were simultaneously loading supply with some hefty coincidental peak demand, and electricity ain't cheap particularly in the UK.

If you were measuring each major circuit separately, a 45A meter could easily cover all sockets, another could cover all lighting, each with a kWh pulse output, all you need is space for 2 standard DIN units, or 3 if you had a high load such as an instant shower or cooker. These will comfortably measure kWh to a high degree of accuracy, pulsing out according to choice of model, probably 30 euro each.

Where expanding the consumer box or adding to it is not physically possible, that is where I view CTs as solution to achieve the objective, but it remains a compromise.

[gohan]

I am using a couple of sonoff pow to measure kitchen and washing machine as they are the most power hungry devices. I am also using a pulse counter on the electric company meter but I figured it is not really working well in reporting instant power readings, while the pulse counter is counting fine but power calculation by domoticz is too slow and I can't use it to switch off the big loads in case of overload ( over here we have 3000W maximum allowed and if you exceed that for few minutes the main switch will cut the power and I was planning to avoid those situations with the help of the sonoffs pow)

[raptorjr]

@gohan Just curious, where do you live with those restrictions?

[gohan]

@raptorjr Italy, that is the most common contract for homes, but there are other contracts with 4500w or more and you get charged with an higher fixed monthly fee for the extra power availability even if you actually use it once a month

[kimot]

@gohan
5 min interval is not big problem for me.
Problem is, that this last 5 min interval in each hour is completely lost.
They do not add it to next hour.
Next hour is calculated from hh:mm:00 again.
So first interval hh:00:00 to hh:mm:04.
InfluxDB is good, but I want all at one web ( domoticz ).
I try calculate power consumption myself through some Domoticz script.

[terryrow]

@shabba I have used a clamp meter and arduino uno to monitor power levels, disadvantages are that you need to full wave rectify, provide load resistor and smoothing. Measurement becomes a bit of guesswork as to how many volts o/p in a Kwh.
Here in Britain, meters have a LED that flashes 1000 times per Kw. I have used a digital light sensor input into arduino uno digital input and then measured the time between flashes in msecs to give accurate readings. I use have used both methods to monitor solar panel output, then turn on Leaf BEV car when sufficient free power is available and off again when clouds arrive. Next step is to o/p readings to a Nextion for both solar and grid power readings with adjustment of turn on thresholds to optimise summer and winter useage.

[gohan]

@terryrow do you mind sharing your pulse meter code?

[zboblamont]

@terryrow Out of curiosity, was there no output pulse connection on the meter, or is it a sealed 'smart' meter from the supplier?
Wh pulses appear to be rare on supplier provided meter which piqued my curiosity, they are generally kWh pulses...

[gohan]

Our utility company meters have a flashing led that flashes 1000 times for every Kwh, so 1 flash is a wh

[zboblamont]

@gohan said in Whole house power monitoring.:

Our utility company meters have a flashing led that flashes 1000 times for every Kwh, so 1 flash is a wh

Fair comment for Italy, but I do not recall similar for the UK, although I must confess I had little interest with respect to monitoring systems at the time.

In Romania they have the habit of placing smart meters with pulse flashers in rather large acrylic bubbles (a la Klockner Moeller) out on the main road, which not only renders optical detection difficult, put potentially removeable by every passing drunk.... Hence placing a padlock on the isolator access to dissuade the same folks from switching off the entire house from the main road...

[terryrow]

@zboblamont I cannot see any sockets for a digital o/p. Neither is a smart meter, but both are only 2 years old. The grid meter has an additional green led when power is going out of the house.

[terryrow]

@gohan Sorry I have been so long, some things, apparently, are more important than playing on my laptop. I managed to lose the "saved" copy when looking at Nextion mods. I have recovered/repaired and tidied the code but I need your help as to how to share with you.

[zboblamont]

@terryrow Sorry, perhaps I am misunderstanding your scenario in thinking it may be similar to my own.
I cannot access the supplier's meter or optically couple safely as explained above, but I can shut down power to the house, which allowed fitting of a DIN mounted meter in the consumer box. This has both external flashing LED and 2 connections for pulse measurement via clamp screws.

If the house meter is less than two years old, it will be digital, and these USUALLY have a connector for external pulse.
If you can physically access the meter, google the make and meter type for info, perhaps you have a model with similar pulse connection available. Hence my query...

[gohan]

@terryrow just use pastebin and send the link

[terryrow]

Hello Gohan, unable to find the paste bin or any help section. I need more precise guidance please.

[gohan]

pastebin.com

[terryrow]

@gohan Thanks, eventually worked it out. https://pastebin.com/D0Cc8TSG should do it for you. writing to the Nextion is creating difficulties.