Hi all,
I’m looking for a reliable smart plug with current/energy monitoring that meets these requirements:
- Ideally <1s time resolution (I need fast updates, not just averaged every few seconds.)
- Wi‑Fi connectivity preferred, with MQTT client support out of the box (similar to how Shelly devices can publish to a local MQTT server when the load current changes. I'd rather not have to poll a device's HTTP endpoint a few times per second.)
- Provisioning/config: Bluetooth for setup would be a big bonus (I think the Shelly Plug S Gen3 can do this, too.)
- Reliability/manufacturer: Needs to be from a well‑supported brand or at least something that’s proven stable and not a "cheap no‑name" option.
I’ve been testing a few devices already. Most average power consumption over longer periods, while e.g. newer Shelly devices come frustratingly close to being exactly what I need.
Does anything on the market provide sub‑second resolution for current measurement? Most consumer plugs I’ve tried either average readings or only publish once every few seconds, which isn’t quite enough for my use case (measuring transient behavior and categorising operating modes of certain appliances).
Has anyone come across a plug that ticks these boxes? Or maybe a hidden configuration with Shelly devices that I’ve missed?
Thanks a lot for any help!
Edit: What I’m actually looking for is a fast response time to significant changes in power consumption (by more than a set amount or a percentage), so a high sample rate within the plug. A constant delay until the message is sent out wouldn’t be a problem at all.
curious what you are planning on using it for
The goal is to measure precise on-time for certain kitchen appliances, and to be able to differentiate operating modes (e.g. standby vs. operating, potentially power setting when on.)
It's not exactly that, but let's say you'd like to measure exactly how long a mixing device is mixing something, and you could guess the speed setting with some confidence.
It actually isn't so much about receiving the data as fast as possible, but about precision in timing, which the plugs I've tested so far don't really offer. Best I have seen so far is ~2s delay with a standard deviation of up to another second on a Shelly AZ... Not good enough. The investigation continues.
@tofubl
I use smart plugs frm EVE and ONVIS and both show the behavior you describe.
On the other hand I have several Shelly EM respectively PM and those reliability report any change virtually immediately.
In my RV I even use a Pro4 PM to manage the 10Amp breaker: Electrical heating draws roughly 8 Amps so when the toaster or coffee maker are switched on the breaker would fire after a few secs. ->
Hm, is it possible that "virtually immediately" means different things to us? I have now thoroughly benchmarked a Shelly AZ and am currently investigating a Shelly PlusPlug S (Gen2 I think), and they are both far from where I would like them to be.
Here's the result from a 1.5h run, toggling the load every few seconds:
The PlusPlugS V2 is even worse.
The real problem with this, other than delayed and missed events, is the standard deviation. A constant delay would be okay.
@tofubl
These are all smartplugs and I confirm that behavior with those i have, they are great for energy metering but not real time power monitoring .
The Shellys I use are those: https://www.shelly.com/products/shelly-pro-4pm
Ah, I see. I thought EM and PM are just other smart plug models. Sadly, not a viable solution for me- I need it to be a smart plug type of device. I wonder if those have more precise or faster measuring circuitry or if it's just a different firmware for a different use case.