I just got a Sengled NB7. I’m using the generic Zigbee outlet driver and I configured power monitoring for 60w and flash rate to 750ms or 5s. I have a battery charger for my Worx yard tools connected. When I powered it on manually I got a power event showing 42w. I setup a basic rule to turn off the outlet when power drops below 2w. I checked this morning and it was still on. I turned off through HomeKit, and got a fresh power event of 0w, THEN my rule fired turning off the outlet.
I have no idea what "flash rate" is or does, but I left all of mine set at the default (750ms).
Other folks probably will have better ideas, but when I set up my power-reporting plugs (ZW or ZB), I start with a fairly low reporting value, then run the appliance itself and watch the live logs -- that gives me a useful baseline of what the power reports are when the appliance turned on, while its running in the desired state(s), and then turned off.
Then I refine the power reporting value on the plug to balance catching all of the events I want to catch without spamming the mesh too unnecessarily.
Depending on how any corresponding rules are set up, using a Private Boolean can be a nice way to ensure any intermediate power reports don't do unexpected things to your rule.
The "Flash rate" is the speed at which the switch will cycle on and off, when the "Flash" command is activated. To stop the switch from 'flashing', simply press Off.
I don't use power reporting to monitor or track energy usage per se, I simply want to know if the corresponding appliance is on or off. So I have no interest in graphing anything.
My corresponding logs show power reporting events according to how I have them set up in the respective driver. Some drivers are pretty basic in those available options (e.g. the Generic Zigbee Outlet driver), while others offer numerous options (e.g. the Aeotec Smart Swtch 7 driver)
For power monitoring, I've tested the Third Reality Zigbee Smart Plug and the Sonoff S31 WiFi Outlet. Both seem to work well in reporting power usage. The Third Reality Plug easily connected with my HE 7 hub and works with no issues. Since the Sonoff S31 was WiFi-based (not Zigbee), I needed to flash it with a custom firmware (ESPurna) and use a custom driver that I created to work with HE. The Third Reality was $13 US and the Sonoff S31 was $8 US (on Amazon.com).
I also wasn't interested in graphing. Just by observation I believe entries are only logged upon a change, so your graphing software would have to understand showing the change as sudden at that point in time rather than just drawing a line between 2 points.
My main use case is to automate my battery charger. I don’t want to leave my worx batteries charging indefinitely. I had a SmartThings plug that let me automate on the power draw, but some software updates broke it. Does the power reporting only upon a change work with this kind of automation?
I use my Kasa EM plugs (KP115's mostly) to control charging of a few tablets to try and keep them between 20-80%, but that relies on using Tasker to report back their battery percentage.
With your Worx charger are you intending to look for a slowing in the power being drawn to signify the end of the charging cycle?
In a few other use cases for EM plugs I use thresholds to indicate things like the door being left open on my Microwave, my humidifiers water resovour being empty, my dehumidifiers needing to be emptied, etc.
I do something similar using an energy reporting plug. In my case, it is to maintain a MacBook Air at about 90% when I charge it. Although I don't make direct use of charge status from the device.
I noticed that when the MacBook battery level hit about 85%, the power draw dropped to below 10 watts. And it took another 10-15 minutes for it to reach 90%. So I've used this Node-RED automation for the last 2-3 years. It shuts the charging outlet off 10 minutes after the power draw drops below 10 watts.
I kind of skipped over this in my response, but I think @aaiyar 's example shows that normally with any battery charging (at I think this is true), there will normally be some fluctuation in the power being drawn, at least towards the end. So you should be able to use this to determine when you are approaching the end of the charging cycle, like @aaiyar 's example. You will, like he also explained, need to understand the pattern that occurs when your batteries are being charged, so you can best configure any rules.
The SmartThings plug was Wi-Fi. Samsung changed something in their horrible transition from old to new and it stopped working.
When it was working, I noticed the power draw of my worx charger to max out at 42w within a minute of starting and trail down to 0 in 2-4 hours when the batteries were done charging.
If I can’t get the EM to trigger the same on this outlet I’ll either return it or just add to my good night routine to turn it off. I’m not worried about turning it off the second it finishes, just don’t want to leave the batteries charging for weeks or months in the off season.
I am a fan of the KISS principle. Thus, if it were me, I would probably write a very simple Rule that automatically turns off the smart outlet after ~4 hours, once the outlet is turned on. This way, it is simply a matter of pressing the button on the smart outlet to initiate a charging cycle. I would probably also add a command to turn it off at a specific time of day, each day, just in case the 4 hour timer somehow got missed (e.g. during a power outage, as some outlets return to their last state upon power restoration.)
