With all due respect to everyone who wants to make suggestions to remake this device before trying it out, I’ve spent a year wrestling with scores of design issues and this is the result. There is a thread for “Homebrew IotaWatt” where there are already several folks that are doing the hobbyist enthusiast thing. I am supporting those efforts to the extent that the proponents are actually building the changes they would like. In the end, I suspect there will be some feedback of those efforts to this production unit.
For now, understand that I designed and built this device specifically to be useful to those who do not want to build and modify their own devices. I wanted to eliminate the need for a perpetual thread in these forums telling folks how to calibrate and reprogram their device. I wanted to offer the average person the ability to monitor their home use, PV or other alternative, solar diverter, EV change appliance, whatever, with simple plug in CTs and browser based menu picks. If there is anyplace I would like to concentrate my efforts going forward, it’s in improving accessibility to non-technical users.
So this is a fork in the road. Folks who want to start their own redevelopment thread can move to homebrew and I’ll be there to share my past experiences to inform those efforts. Those who want to just use IotaWatt as a data collection device and talk about how to do that and what to do with the data, I’ll be here to help with that.
There’s something for everyone - all it’s proper place.
IotaWatt was designed with the intention of having 3-phase capability. At this point it’s all academic. I don’t have ready access to a three phase installation to further develop and test the capabilities. There are a couple of folks on the homebrew thread that are playing with that in European 3-phase residential settings. With this rollout, I’d like to start working with field people to explore these capabilities. I have some parts coming in soon to make simple adapters to allow using any channel as a voltage reference channel.
I’d like to start a three-phase iotawatt thread to focus those efforts and provide more specific support to the various approaches possible with IotaWatt. I’ll set that up within the next day, and ask that you go there and we can start to define and elaborate on these three-phase concepts and solutions.
It will be difficult since the ESP8266 uses considerably more power than an ATmega328 (used on emonTx) when WiFi is connected. If you really want a single AC adaptor solution you would be better off using an emonTx. See our blog post on the design of the AC-DC half-wave circuit used on the emonTx.
More congratulations to @overeasy and @glyn.hudson for development, testing, certification and bringing IotaWatt to the community. Thanks and well done!
Unlike the IotaWatt the calibration factor on the emonPi / emonTx is set in the firmware. It would be possible to use different CT’s but the calibration / phase shift would have to be updated in the firmware. This would not be an issue for technical users to re-compile then upload the FW but not all users would be able (or want) to do this.
Long time lurker here, but your post is timely to what I am working on.
I am about to start testing multiple CT options (both split and solid core) from YHDC for the monitor that I am developing. I will be happy to contribute my test results in due course.
Hi Bob, congratulations on the release. Is it possible to order through the Open Energy Monitor store and have it shipped directly from your shop to New York (to save shipping cost and get it faster)?
Hi Earl, thanks for the kind words. I’m sorry that I’m not equipped to fulfill US orders. I’m trying to remain an OEM (original equipment manufacturer) and let OEM (Open Energy Monitor) take the lead on retail. They do some final assembly, add a component, label, load production firmware and test. They have a dedicated person who will do a professional job. My 160 sq ft office/lab on the other hand… At least you don’t have to pay VAT.
@overeasy: Do you have any idea of the memory consumption on the SD card? (i guess its channel related) The specs page mentions 8gig sd card minimum, but you picture in this tread (very top) shows a 4 gig card.
What happens when the sd card is full?
Jan, the datalog is still in a bit of a flux. You are safe with either a 4GB or 8GB card, but I would recommend going with 8gb for the long haul. This type of memory has wear management built in, and over a number of years some of the blocks can be at their statistical end-of-life. There are enhancements to the datalog system in development that will support up to ten-years of historical data at a lower resolution (1 minute), so spending the extra couple of $ for 8Gb is a good investment.
