New here - need advice

Hi all

UK based. So I have a 4kw solar system, which feeds the solar meter located in my utility room. Also there is the main house RCD boards.
In the remote garage is my main electricity meter. Just after the meter the supply is split. One tail running to the utilty room, the second tail to the garage RCD board. This supplies the garage power and also external in the garden I.E. Hot Tub

So what is the best way to incorporate this system onto my setup to monitor the solar generation and the total household consumption


Welcone, Denzil, to the OEM forum.

I think, depending on how much solid house is between the utility room and garage, which will determine whether the 433 MHz ISM band radio will reach, you need an emonPi in the utility room measuring the house consumption and the PV infeed, and an emonTx in the garage measuring the nett grid power and garage consumption, both with 2 c.t’s and an a.c adapter, and the emonPi also needs a 5 V d.c power supply. (So a single socket for the emonTx, a double for the emonPi.)

If you’ve got decent Wi-Fi coverage in the garage, you could swap those around and have the emonTx in the house, giving you the availability of two spare channels in the house should you want to measure a couple of circuits independently.

If the integral ISM Band radio won’t reach, then if you have WiFi coverage in both places, you can add the ESP8266 module and a 5 V d.c. power supply to the emonTx (so a double socket now), to use WiFi instead of the 433 MHz ISM radio.

(Please can you add the country you’re in to your profile. From the way you write, you’re in the UK, but it’s helpful for us to know because different countries and jurisdictions do things differently.)

I have good wifi both in Garage and utility room. There are at least 3 brick walls in line of sight from the 2 locations.

I already have the 4-noks early CT clamp system on din rails at both locations. Can this be incorporated hence reducing some costs?

That could be a bit iffy. Although it might be worth trying the radio, I think you might have problems, I’d go for the Wi-Fi option.

If you’ve got details of those c.t’s and they turn out to be suitable (with or without a small hardware modification to both emonTx and emonPi) then yes.

What you need is, with their burden resistor, they can deliver approx. 1.1 V a.c., or 50 mA without modifying the emonTx/emonPi inputs, at the maximum current you’re interested in (that’s nominally 100 A in the UK for the grid, 16 A for the P.V. infeed). That’s quite often a tall order: there is a huge choice of c.t’s that deliver 0.333 V rms, not so many that have the VA rating to manage 1 V rms.

Hi there

Link to the datasheet (In Italian) for the CT clamps. This is the latest version, mine is an earlier one so I would have to check its the same. Not sure it really tells you what you asked.

Unfortunately (and as I expected), that doesn’t tell me anything about the c.t’s except their 70 A rating. There’s nothing moulded into the case or printed on them, and I presume you don’t have the ability to do any tests on them?

I couldn’t see any info on them! Not sure how to test therm

One thought - these are z-wave so can the raspberry pi devices read z-wave. If so I should be able to connect them?

Are you thinking of keeping the whole 4-Noks system then, and picking up the data from it? And what is that ‘old’ system monitoring at present?

If you are keeping it, that’s going to be possible if you can get hold of a suitable receiver (likely to be easy enough - I found this), and that also seems to imply that it’s standard Modbus.

It’s been decades since I did anything with Modbus, so I’ve most likely completely forgotten everything I once knew about it.

So yes, I have a small LCD style display unit - I will confirm the name of it later today.
This takes the signals from both CT clamps and gives me from the top of my head the following
Current generation Kwh
Current bought energy Kwh
Current exported energy Kwh
then it must do some processing as I can download via USB cable to a PC and get daily stats down to I think an hourly basis of all of the above data

So this little device must read ZigBee from the CT clamps.

Just found a site with basically a diagram of what I have

Not quite - that data sheet you linked to shows what appears to be a DIN-rail meter with a c.t. on the grid connection, with a c.t and remote “Smart” transmitter on the PV infeed, communications between the two presumably using ZigBee radio. From the diagram, it appears that the “Smart” transmits the combined data to your display, so it’s that which you need to intercept and decode.

OK so I got this from another foreign site

IntellyGreen PV is the only wireless system on the market, easy to install and easy to use, regardless of the inverter installed, to verify the photovoltaic system’s electricity production and efficiency.
The remote wireless display to be placed in your home allows you to read the most important data such as the gain in euros thanks to your system, the instant power produced, the peak power, the energy produced, the performance in hours, the data history up to two and a half years, the display and beep of an alarm read by the radio transmitter. You can also download the data history for spreadsheet analysis to your PC thanks to the USB interface.
In addition to the remote display, the basic kit consists of an innovative optical interface, (patented) to be applied to the counter and a radio transmitter. The optical interface reads the electricity produced and is connected to the radio transmitter that, with 2.4 GHz ZigBee technology, communicates the measurement of the electricity produced towards the remote display; The radio transmitter also has a digital input to remote an alarm (e.g. the inverter).
The photovoltaic panel’s radiation and temperature sensor is also included in the base kit. The sensor has a temperature probe to be applied to photovoltaic modules to detect the temperature of the photovoltaic modules. Radio with 2.4 GHz Zigbee technology to the remote display the measurements made of solar radiation and temperature of the panels, so that the display can calculate and display the efficiency index of the system.
The sensor is powered by a solar cell and a back up battery, which has an average life of 5 years. It comes with a repeater device in case the distance between the display and the radiation sensor is considerable.
The patented IntellyGreen PV system uses Zigbee technology that guarantees low emission power (one thousandth of that of mobile phones) and high reliability of connections.
IntellyGreen is a 4-noks brand

So can I use a raspberry to get the ZigBee radio data and then manipulate it onto the systems seen here please?

If what I’ve understood is correct, you need a ZigBee receiver to get the data into your RPi, and you need to know, or reverse engineer, the data it picks up and convert it into a format suitable for emonCMS. I don’t know that anyone here has done that before, so I can’t point you towards any experience. There are people here who use Modbus, that itself isn’t a problem. Modbus data exists in registers, you ask for and get back the data in a register, the problem is knowing which register to ask for and what the data you get means.