When you specify more than one VT, a voltage reference specification appears in the CT input edit dialogue. Was in the old app, dropped out in the remake, is in my current version. Was always in the code.
Its all about the log file. Currently whites 256bytes every 5 seconds. That’s about 1.6GB per year. My current design will probably use half that. So depends…
You should ask Mr. Wall for a lesson in burden/turns/current, or read his excellent tutorials in the learning section. The reason I added 1.2V in the adafruit feather design was that I have some revenue grade .33mv CTs that I came across on eBay for short money. Truth be told, with the 12bit ADCs, even those work fine at 3.3V. I have abandoned 1.2V in my latest design. I have an HCWT-004 monitoring a solar inverter at one installation. 3.3v 24ohm burden. The thing has been within 0.1Kwh of the (Solar-Edge) inverter web monitor application, which is revenue grade because it is used as a basis for SREC (Solar Renewable Energy Credit) payments. Not bad for a $1.98 CT.
I see a potential problem in that one side of the VT goes to ground through a 10uf capacitor. If the polarity is reversed between the two IoTaWatt devices, and any elements of the DC circuitry are connected (like the ring of any 3.5 mm stereo jack), you will have a short of the 9VAC, potentially through the DC circuits of one or both units. So the answer is it can be done but has to be done with strict observance of polarity.
I had gone with the Adafruit components in the hope that I could convince Adafruit to build an ADC boads to round out the hardware and make it available to people. They don’t even answer emails, and their stuff is relatively expensive, especially with their shipping. So I have given up on them and gone back to the $5 (free shipping) nodeMCUs which work fine. I have put the RTC and SD on a board with two ADCs for a 14 channel + VT 3.3v design that is working great - all SMD except for the nodeMCU.
The final board went to PCBway today, should be back in a week. I have sourced an enclosure, have samples, and am waiting for a quote on machining the openings. I have an excellent local assembly company that is quoting board production. So I will need to decide soon if I go to market with it.
Not really sure what you are doing. I get the sense that you may be associated with the OEM people. Last I heard from Trystan Lea, he played with the device I sent him for half a day, left it connected as voltmeter for a few weeks, then it went off the air. Not a word from these folks, so I am considering that overture as dead as the Adafruit effort.