Sonoff to monitor a washing machine


#1

I was all set to use a Sonoff POW to monitor my Miele W565 washing machine and let me know when it’s done with a cycle…but having seen the scary thread regarding the modified Sonoff and at least one person chiming in with a similar (but unsubstantiated) report of Sonoffs going up in smoke I’m wondering what the consensus is…should I do this and if I DO, what can I do to mitigate the risk?

Thank you…


#2

Check the electrical ratings for your machine.

A POW can handle either 15 or 16 amps on a US 120V circuit. I believe the its the same for a 240V system but do your own research either way. I have one on my washing machine and feel very comfortable as the max the machine should pull is ~half what the sonoff is designed for. Additionally the POW is fused which provides some protection should the current rise beyond what is listed on your machine.

Be sure to utilize wire that is appropriate for a 15 amp device when you setup the sonoff.


#3

Hmmm - really not sure - seem to be three people in this thread talking about their Sonoffs going up in smoke and or flames.


#4

A 16Amp cyclic inductive load will for sure kill the POW. That rating is for resistive loads and you shouldn’t run these things at their maximum rating for long anyway.

However I have a POW 2 on my washing machine, it never draws more than 1KW @ 240V (~5Amps) and has been running fine for months. There are also Australian electrical authority approved versions of the POW 2 linked in that thread. They cost more but might give you a bit more peace of mind.

As @silvrr said, check the electrical rating of your machine.


#5

I am not familiar with that dryer, but mine is gas fired, and I used this for my configuration of the S31’s:

Hope it helps!


#6

I run a POW on my electric dryer, no issues yet…


#7

Do you think merely monitoring an inductive appliance with a POW is safer than SWITCHING an inductive appliance??


#8

same think if the current is going through the relay


#9

Oh. Thanks. I’d wondered if switching was potentially a pinch point with contacts getting welded shut/open. Thanks again.


#10

Not exactly what you’re looking for, and don’t want to side-track this thread, but just in case you hadn’t thought of it yet, another option that people do for this is use vibration sensors. Take for example, Samsung’s Zigbee Multi-Purpose sensor, which has a vibration sensor put in. Just place it right on top of the washer/dryer and have it fire when vibration stops for 10+ seconds letting you know the cycle is over. Cheap/easy/and most important safe. Although, as with any project you should research the reliability results of those who have done it before.


#11

That is a possibility. There’s a Tasmota setting that keeps the relay always closed. I use this to hedge against such possibilities (though admittedly not on a washing machine).


#12

What about power monitoring like the following, uses CT clamp so avoids inserting device into circuit.
https://learn.openenergymonitor.org/electricity-monitoring/ct-sensors/how-to-build-an-arduino-energy-monitor-measuring-current-only

I have one setup just posting power usage of hot water to MQTT, basically so long as power usage over 50watts I know hot water element on (when off it actually records random power usage up to around 50 watts).

I plan to try on washing machine as well, in theory I should be able to work out what part of cycle is if I record power usage?


#13

Thanks - that’s potentially a good shout - but I’d still need to strip the insulation back, right?


#14

I had one built to do testing which I got a short extension cord, cut insulation off that and setup. That way I could plug anything into it and more importantly not altering appliance cords which would be a pain if removed sensor, sold etc.
Will do something again next time, putting any stripped cable, electronics etc in a box.