I am a beginner. Self-thought via youtube - dangerous, I know!
I’ve had an issue with 2 Sonoff SV’s burning out when connecting them to my alarm system.
Both were flashed with Tasmotoa.
Both had the two tiny resistors removed so it can be used as a dry contact relay
Both were set up and tested using a 5V power supply to the two dedicated power pins and worked fine
However, when I connect them to my alarm system things get smelly. The second time, I disconnected the alarm system from its battery, tested the battery with my Voltmeter (it tested 13.8V) and then connected the SV to the battery with nothing else connected. It immediately fried.
I understand that the SV can accept power safely from 5-24V DC. What am I doing wrong?
Appreciate any help, feel free to explain like I’m five.
That’s correct, I used the two pins at the bottom of your diagram where the green arrow is pointing to. The two inputs you crossed out, I bridged so I could use the two outputs at the right of the diagram to go to my switch.
O yes, sorry. That is what I mean by bridged. I shorted out the inputs on the left of the diagram. (So the circuit is completed from the -Output, through the relay, to the +Output)
Awesome, thanks so much. That’s something I can not do next time.
Just to be clear, you’re saying I may have connected the live wire to the - on the board making the “flow go in the wrong direction”?
In the spirit of learning more, how could you tell?
I just did this same thing I covered the board writings for the polarity with some soldered on screw terminals and so googled a pinout to try and remember which was which… The pinout I grabbed was wrong! … and I didn’t take the time to double check because I wrongly assumed that there would be some reverse polarity protection… I take it that once you make this mistake you just generated more e-waste… anyone know how to revive this or is it just dead? Supplying 12v correctly, I can see that the relay is receiving about 7v and the 3.3v pin is receiving 3.3v so the power supply part of the board is still working, but the chip is unresponsive… I tried re “tasmotizing” it, but no such luck.
In the images supplied above it looks like the smps ic has also suffered some damage. May or may not be the same on yours. If you can do SMD soldering you could repair any blown pcb tracks, replace the input smoothing capacitors and the smps ic.
If you don’t know what you’re doing, don’t try it.
Without proper damage diagnosis, you can cause further damage.
I’d rather use another one, I wouldn’t trust the victim anymore.
I understand that it is non-functional. And if it could be put into operation somehow, I probably wouldn’t trust him anymore because I’m not sure if anything else is partially damaged.