Shelly Plus 1PM died but why?

[Matthias_w]

Hi community,

I have connected the Shelly Plus 1PM in front of a power outlet and plugged a Hoymiles HM800 inverter into it.

The Shelly was reading the power from the inverter for a week and then stopped working.

I have opened it and found what you see in the attached image.

Any idea what could have caused this? Would help me to find a possible problem in my home electrics.

Thanks

Matt

 

[thgoebel]

Inductor L7 is faulty. This is most likely caused by another faulty device: The step down converter BP2522. A sketch of the power supply shows the components:

 

Very likely, the course of events is as following: Diode A7 gets faulty and produces a short circuit, which opens AC to the components beyond it. This damages the BP2522, which has a “buried” diode, and possibly the two electrolytic capacitors 4,7μF. Due to the high current, inductor coil L7 fuses. This should be the gentle duty of the fusible resistor 10Ω - but it is not very reliable…

There exists a chance that a fluorescent tube in your premises has caused high voltage spikes during the start cycle, which may be liable for the faulty diode. Would recommend to look for those lights and replace it with LED lamps…

 

 

 

 

[Matthias_w]

@thgoebel wow, what a great and technically sound assessment!

There is actually a lamp with two fluorescent tubes in this room.

I have already bought an LED bar, but was still too lazy to install it.

This gives me a perfect reason to do so and also buy a new shelly.

I will keep you posted ...