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)

I want to confirm that this product (SONOFF S40 WiFi Smart Plug) works with 220v-240v, I asked this question here in this product page if it supports 240v but all answers I got were guess work saying that it might not work (I wonder why people answer if they dont know), guesstimate was not the answer I was looking for, when it is written 110v I too can understand it might not work. I bought this one (knowing the risk of it not working) to use in my home country Nepal where electricity is on average 230v. So, yes this one worked successfully in 230v, I hope my answer will help people like me who will be looking to know about this issue.

I needed a method to measure electricity usage on my solar water heater backflush system. It has 1 small pump that moves the heated fluid from the rooftop solar panel to a heat exchanger tank, then another pump draws cold water from the bottom of water tank thru the heat exchanger and dumps the heated water into the top of my tank. The pumps run only when the temperature sensor on the roof senses the temp is warmer than the cold water in the bottom of my tank, so it happens sporadically as the weather changes. This device lets you put in the cost per kWh so it shows the actually cost of energy. Works perfectly for me. Also, these pumps only use about $5 of electricity per month.

Easy to pair and get it working. Alexa, lights on, Alexa lights off! This plug is very handy! I am going to use it for my Christmas tree when its time! Looking forward to not having to struggle with the outlet each night.

Tried for days to pair and almost returned them. Most only searches so older versions of the app and the app is not intuitive at all. It is very picky with how your wifi is set up. The Name(ssid) and passwords Can Not have any spaces or special characters. This was a challenge because we are not able to change these without have to re setup all our other devices. Some are security cameras that are very difficult to get to (26 high and 1/4 mile from our router). Our router is only 2.4ghz but the app kept acting as though we were trying to connect to a 5ghz router. Ultimately we had to add a Guest Account named Letters only and set the password with the same restrictions (which makes for a very weak password). Once paired...whew, It seems to be working. The app does Not give the level of detail I was hoping for. It only provides total daily power usage or instantaneous usage. I wanted to see what time the refrigerator defrost heater came on, for how long and how much power it used but the app doesnt do this. With all this considered it is a good value and we may even buy more now that we are able to pair them. One star deducted due to the app, not the switch itself. Although, if the devices continues to work well over time without loosing connectivity or failing we will update to full 5 stars. We were able to determine the fridge pulls about 1amp/120watts while the compressor is running and a total usage of about 0.9kw over 24hrs. The hair drying on high heat and fan pulls over 13amps/1600watts which is almost the max rating of the device. Be careful not to overload. Only ran for a moment so cant speak to how long it can handle this level of current draw. Lastly the basic math calculation is not 100% accurate which should be very easy to accomplish. Volts x Amps = Watts. The device measures the amps and the volts and calculates the watts. They were reasonably close but not perfect. See image attached, should be 126 watts.

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.

These are easy to use. As Im getting older, I love telling Alexa to do stuff and she does it. Obeys better than my kids did, lol.

I love these smart plugs, it’s very affordable and it really works. You can monitor all your appliances for power consumption and integrate in home automation with any kind of platform - alexa or google to name a few.

Flashed Tasmota, and calibrated power use. They are working great, except I found out my deep freeze uses a lot more power than I thought it did.

I really wanted a smartplug with good energy monitoring data. However, this device/app only gives you historical data in per day units and only in kilowatts. What about per second/min/hour? Or amps/milliamps/kiloamps? Or regular watts? As such, this only really is useful for recording your daily energy usage. As such, this is useless for someone like me, who is looking to observe changes in electrical consumption when I plug in/out any device in the house, or when I turn on/off a fan or anything else. The data also updates very slowly, taking a minute or two to read the energy consumption, and is incorrect. I have another energy monitoring smartplug that gives consistent rapid accurate data, and the SONOFF branded one is always off. This gets 1 star for being somewhat functional and an additional star for the price per value, but at 2/5 stars, I recommend you look at other options.

I used them for a week with eWelink, and after two days they no longer reported power consumption quickly, or at all. I tried flashing them with ESPHome to test if they were bad and nope, they were perfect, and i was able to read power consumption super fast (down to 0.2s) and accurately every time. If you are considering buying them, go ahead, they are excellent if you flash them with Tasmota or ESPHome. Do not buy the S40/S40 Lite if you plan on flashing them (Very hard to open and uses the BL602 chip, that isnt supported by literally anything). And finally, remember the S31 Lite DOES NOT have power monitoring