I’ve got a emonpi which comes with support for 2 CT clips, that I’m already using. I’m getting a myenergi EV charger and would like to measure the watts when it is in use. My current approach is to just add a CT clip on required cable as my emonpi is very close to my consumer unit.
I already have an emontx upstairs for other monitoring, but don’t really want to buy another emontx just for one ct clip. Is there any other way of the emonpi communicating with a CT clip such as Dallas, 433, usb, mqtt etc?
Do you mean the SCT-013-000 split-core current transformer that you’re using with your emonPi?
The c.t. itself and the c.t. input of your emonPi is 100% analogue, all the things you mention are digital. So without in essence replicating the analogue circuitry and the ADC inside the emonPi, the answer is no.
You can extend the c.t. cable, so if it’s practical for the cable run, and you have a spare input on your emonTx, you could do that.
As Robert says, no 3rd CT however I think you could have a look at whether any of your sources can be monitored with an LED Pulse sensor rather than the CT; the input from this would be via RJ45.
Generally speaking, pulse inputs are good for a measurement of accumulated energy, they have distinct disadvantages if you want an indication of power, and that’s why we normally advise using a c.t. if power measurement is the primary objective, with a pulse input (if available) as a calibration source.
Also note that there’s no kWh meter that I’ve found or heard of that can give a proper bi-directional pulse output, most give pulses for energy flow in one direction only, some don’t distinguish between import and export - which is even more useless especially on the grid incomer if you have P.V. or another source of generation.
Yup I was referring to the SCT-013-000, sorry for any confusion.
I was kind of hoping there was some smaller/cheaper alternative to the emontx for a single input, maybe using an arduino etc to perform the analogue conversion and then send over 433mhz.
You can use an Arduino, you’ll need to add either an emonTx Shield, or make yourself a single-channel version of the emonTx Shield. General information as always in Docs → Learn → Electricity Monitoring, circuit diagrams are probably still somewhere on Github.