SONOFF S31 WiFi Smart Plug with Energy Monitoring, 15A Smart Outlet Socket ETL Certified, Work with Alexa & Google Home Assistant, IFTTT Supporting, 2.4 Ghz WiFi Only (2-Pack)

The S40 brings a new elegant and a little design to the previous one. It is amazing what you can do with the power consumption capabilities. And the best of all is the automatic turn off when there is an overload to protect the connected device. All of its smart options are as expected, they are even better when you have other Sonoff products. For example, I can turn on my wall plug when I turn on my light switch and more, just with the app. Overall, it is an incredible product and a must have in your smart house.

I bought these to use with Tasmota and it works great! Easy to disassemble with a screwdriver and a spudger, easy to solder points that are clearly labeled for programming, and doesnt look scratched up from disassembly at all. The Tasmota software is even able to see the power factor, watts, apparent power, volts, and amps! I didnt try the app that came with it, it probably sucks as most smart outlet apps do.

Works well with Home Assistant.

I bought a single S31 to replace an unreliable Fibaro Z-Wave switch. I never even bothered to use the original S31 firmware. I took it out of the box and flashed it with ESPHome under Home Assistant. Worked great the first time with no surprises. The power monitoring seems to work, but I havent bothered calibrating it. If it continues to be reliable over time, I will definitely buy more of these.

Update: It appears that I have spoken too soon. Out of the 6 total units that I have now, 2 of them will not power on or pair (I am 7 days in the dark with their customer service with this so far) and 3 of them randomly read as Unavailable. Looks like Ill be sticking with Wyze outlets for the future. Disclaimer: I ordered these to run on my Home Assistant (HA); I have not tried using them with any other system or integration. This review is for the S40 Wifi Plugs. TLDR; I liked the 2 pack of S40 plugs enough to buy another 4 pack and also suggest them to my brother. For anyone running Home Assistant, the setup isnt that horrible, but you are going to have to use the eWeLink app for the initial setup to your network. Additionally, you can get them to be on a local LAN (and not on the cloud) but it will involve some Googling, reading, and some work to get it done. The initial (app) setup was smooth and getting things to work on HA only took a couple of more minutes after doing a little Googling. The energy monitoring seems to be fairly accurate in the sense that a 60-watt LED light was reading approximately 58 watts in HA, but I wasnt proactive enough to verify with the Fluke or Kill-A-Watt yet. (Ill do that and update this review at a later date) At this juncture, Im more concerned about reading energy draw vs no energy draw in order to act as a trigger instead of monitoring energy usage (I monitor consumption at the breaker panel, so I dont really need to do it at the component level yet). The only drawback that I have encountered thus far; if you wish to remove a plug from one network and use it with another, you MUST first go into the eWeLink app and remove it while it is still in the original network before trying to move it to another location (with a different network). In my experience, if you do not perform this step first (and attempt to remove it from the app when the plug is at a different location), the plug WILL NOT turn on nor will you be able to re-enter pairing mode. Im not sure why it was acting like this, but when I returned it to the original wifi network, I was able to get it working without any problems. My original experience with Sonoff was with an S40 Lite Zigbee model and it frustrated me to the point of wanting to chuck it out the window and steered clear of their products for a good while. Thankfully, these (S40 wifi variant) was much easier to play with and my gamble paid off; resulting in me ordering a 4 pack to use within my HA ecosystem as well.

This is a warning to anyone who wants to purchase this that they should consider the App Store reviews for the required app to run these. At the time of writing this, eWeLink-Smart Home has a 2.8 star rating plagued with bugs and all kinds of issues. This app is required to use this device and you need to have an account with them in order to link to your Google Home so when considering this product I highly suggest you consider the App rating. There is also a ton of privacy issues associated as it requires you send your location information, other data, home network access, and identifiers in order to create an account which is your email address. It is also not clear who I am sending this data to, or why it needs persistent location data. This is a Sonoff product that requires an eWeLink app which has the support email going to Shenzhen Cool House Technology Co., Ltd. When clicking on the Privacy Policy on the app store it doesnt actually go anywhere and just takes you to a home page that is in another language and when translated has no links to the Privacy Policy. Not a product I would want running inside my home network.

These were not so easily added to the Alexa controlled system. Instructions did not track with the way I had to install them. The plug is large and the light/button, instead of being on the front, is on the side which means horizontal outlets, depending on orientation, may make it impossible to see the status light.

My wifi auto switches your devices between 2.4GHz and 5GHz, so I cant use this switch unless I dedicate a an old phone. I put my phone on the 2.4GHz band to install it and it worked. However, I cant leave my phone on that band. When I switched back, I couldnt connect to the device. I have other smart devices that require 2.4GHz signal in the house but not on your phone. Bad software design.

Works for medium to large size appliances, but smaller devices that use 5V power (most USB style devices or small devices), do not register on the devices power monitor. It goes to 0.1W, so if your device uses 1W or less, its near impossible to get a positive this device is definitely using power answer from the power monitor data (for use in home automation). All that being said, the connectivity and setup was very solid.

These plug are a nice size and appearance. They come part well if you want to flash it. Flashing it is super easy with a decent jig. Be warned the breakout test pads lift easy if you try to solder directly to the pads. It was faster to print a jig then it was to fix it after the rx pad tore off.