Hi everyone,
I have a bunch of Shelly 1 PM devices (and 2.5) and I am getting fed up with them.
Although rated for 16 A, they overheat as soon as you reach around 2-3 kW.
Does anybody know any devices that are more reliable?
Shelly is really disappointing due to overheating issues, poor power supply stability, broken capacitors etc.. Just really poor quality products.
And yes, I do want to be able to switch the device on & off, not just measure the energy consumption.
Why not let the Shellyâs drive relays that can actually handle the load of 20 or 30 amps. Only draw back would be current/power monitoring. Unless you pick Shellyâs that use a coil for current monitoring and have a switch to drive the external relay.
I am in Germany.
I would like to use an open protocol like mqtt. But essentially anything that does not require âspecialâ hardware is fine, so BLE or WiFi.
Ideally the device can be flashed with open source firmware but that is not mandatory.
Power monitoring is the crucial part. I think that is the part that actually gets hot. Purely turning on/off is not really processing heavy and hence does not really produce heat.
Indeed. For âhighâ currents (or any inductive) I split measuring and switching as well. Inconvenient, but safer.
Although, I used to use Plugwise, they did both quite well, but it needed an USB stick for a proprietary Zigbee-like stack. And EOL. All the good stuff goesâŚ
Your thread title is fighting words and you may want to modify it.
Shelly in your case may be âuselessâ as it may be your choice is inappropriate for your requirements, rather than their equipment you have chosen is faulty?
To put it into context: You are using a Kombi bus to get your entire World Cup team to the stadium - yes you can try, it looks achievable, but practically, it wonât work.
You need devices with far higher specifications to achieve your goals. Doing this on the cheap will end up far more expensive, especially if the under-rated devices doing the switching fail gradually, or intermittently, destroying the equipment you are controlling or reducing their longevity.
I see heavy duty contactors, combined with current transformers in your future. Speak with a qualified HVAC tradesperson - it is their usual bread and butter work, and they know the common pitfalls and solutions you are stumbling over. Your âspecial hardwareâ is their common equipment, not amateur solutions, but robust, proven, and reliable.
The alternate, which I have seen far too often, is a charred or molten mess, or the initial point of origin of a house fire, sometimes fatal. Your choice to persist down this path, just to save a few euros and risk everything. This is one area you do not want to skimp on.
Iâm using a Shelly Plus 1 PM to switch my car charger on with up to 11A for half a day and overheating was never triggered. Are you using old generation Shelly devices?
Are your terminal connections reliable and low resistance?
Poor clamping in the wire terminals has the potential (pun!) to generate considerable heat. Enough heat to cause a fire.
Are you running purely resistive loads or reactive loads?
Reactive loads like motors, compressors or items with large capacitors will require de-rating the resistive specification by a considerable amount (up to 5 times).
âProcessing heavyâ doesnât really matter here. If you break down whatâs really heating up you can estimate better where the problem is. So if we assume you have carefully wired 16A resistive load to brand-new shelly, parts heating up could be divided (just my coarse estimations):
relay coil 0.2W
relay contacts 2W
pcb traces and terminals 0.5W
current sensing circuit 0.1W
power supply circuit 0.5W
esp32 0.2W
So about 3.5W in total which has to be dissipated somewhere. âProcessing heavyâ part is only small fraction here.
When relay ages, the contact resistance raises and so does heating. And like @tom_l mentioned, if you donât clamp your wires carefully, terminal resistance can be much higher.
But overall, if you place poor Shelly in ambient where it canât sufficiently dissipate that heat, it will sufferâŚ
You havenât specified which kind of Device(specs) you have connected to your Shelly(external contact)(Nor where in the âelectricity topologyâ this contact is located i.e far from DIN-fuse, Far from Device ? ) . Some equipment should Not be connected through such âexternalâ contacts, but directly via a dedicated cable(+ an âemergencyâ switch) to the DIN Rail fuse ( with i.e cabability to read power ) Shelly also have such ( Shelly Pro )
It actually performs pretty well. Not bad from cheap chinese 15x20mm PCB-relay inside.
But it would be ignorant to think that you can put whatever type of load, that it doesnât heat-up or that it will last infinitely on those conditionsâŚ
I own them and use them. 240 at 16 amps is not what Iâd try to load that with is my point. Half of that resistive is about it. Tripping at 2kw would be about right IMO.
There are lots of threads on different forums where people have the exact same issues. Shellies are known for bad elkos, sluggish behaviour with tasmota, overheatingâŚ
So no, it is not just me.