Overtemperature problem with Shelly Dimmer 2

  • In my living room I have 15 dimmerable led lights, divided in two zones:

    zone A: 9 leds

    zone B: 6 leds

    They are actually controller by two relays: two finder (see image, with also electrical schema)

    I recently bought two Shelly Dimmer 2 in order to replace my two relays and make my led lights smart.

    I attached the two dimmers 2's using the first schema (with Neutral), which is essentially the same schema of the old finder relay (RP is now SW1, the strange symbol is now O).

    At first glance, both shellys work.

    However, the shelly which is connected to zone A (9 leds), after about 15 minutes of switch on at 100% (~70W consumption) shuts down with "overtemperature". It reports a temperature of roughly 105°C.

    No problem with the shelly connected to zone B (6 leds, ~43W consumption). After some minutes, it reports a constant temperature of roughly 77°C.

    This is a status captured roughly one minute before one of the shutdowns.

    {"wifi_sta":{"connected":true,"ssid":"SigiNET","ip":"","rssi":-27},"cloud":{"enabled":true,"connected":false},"mqtt":{"connected":false},"time":"00:08","unixtime":1617746930,"serial":89,"has_update":false,"mac":"E8DB84D6E30C","cfg_changed_cnt":2,"actions_stats":{"skipped":0},"lights":[{"ison":true,"source":"http","has_timer":false,"timer_started":0,"timer_duration":0,"timer_remaining":0,"mode":"white","brightness":100}],"meters":[{"power":67.91,"overpower":0.00,"is_valid":true, "timestamp":1617754130,"counters":[67.861, 67.939, 67.923],"total":2308}],"inputs":[{"input":0,"event":"","event_cnt":0},{"input":0,"event":"","event_cnt":0}],"tmp":{"tC":104.65,"tF":220.37, "is_valid":true},"calibrated":true,"calib_progress":0,"calib_status":0,"calib_running":0,"wire_mode":1,"forced_neutral":false,"overtemperature":false,"loaderror":0,"overpower":false,"debug":0,"update":{"status":"idle","has_update":false,"new_version":"20210323-110201/v1.10.1-gf276b51","old_version":"20210323-11020

    I tried to swap the shellys (so I could exclude that one dimmer is defective), but behaviour is the same.

    The one connected to zone A always goes to overtemperature after a while.

    I tried to repeat calibration multiple times (also with "trailing edge") but with no avail.

    Is there something I can do?

    Should I return the shellys?


    • tmp_finder.jpg

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  • Hello. For 230VAC LEDs, „trailing edge“ should be the correct dimming mode. Which mode is found by „auto detect“?

    Mixed types of LEDs could cause such overtemperature effects. Are all 9 LEDs of same type?

    Maybe old firmware works better with certain types of loads. You could try to downgrade to 1.9.0 and test with trailing edge mode.

  • I have the same problem. with 4 LED equipments totaling 36 w. All devices are the same. After 1 minute it heats up and turns off.

    The firmware is 1.10.1, and the calibration is in "Trailing edge" mode. With the "autodetect type of load during calibration" checkbox checked.

    Thanks for your help

  • Hello,

    in these days I tried everything.

    I set Trailing edge. I repeated calibration a lot of times.

    I downgraded firmware to 1.9.0. I upgraded to beta firmware 1.10.2.

    But the result is always exactly the same.

    After a while with lights on at 100%, the "shelly dimmer 2" with 9 leds (~70W load) becomes hotter and hotter, and when its temperature raises to ~105°C it switches off with overtemperature error.

    First time it happens after about 10-15 minutes of activity. Then, if I switch it on again when it's still quite hot, it lasts less.

    No problem with the other "dimmer 2" with 6 leds (~43W load): it becomes a bit hot (about 95°C) but then it keeps stable.

    As stated before, I tried swapping them, so it's not a matter of a defective unit.

    I don't understand why the shelly dimmers become so hot.

    My previous simple shelly 1's never gave me problems.

    If I keep open the electric box where the shellys are installed, the dimmer with 9 leds does not become so much hot, and it seems stable. However for obvious reasons I cannot keep it open.

    I'm sad... If I don't find a solution soon, I think I'll have to return the shellies...

  • DBA54E58-D9F6-4362-879C-964C350D720C.jpegThe same thing happens to me. on a 70w circuit, no problem. In this one with less than 50w of consumption, it jumps in a minute. both with Neutral connected.

    I have recalibrated, I have changed the intensity in multiples of ten ... it always jumps.

    Would the situation improve by incorporating a bypass? By quantity of consumption it does not seem necessary, but this error is terrible. And it is affecting me in the most attractive circuit of the house of some clients, I cannot fail in this matter.

    Edited once, last by VMoreno ().

  • One question: I installed dimmer 2 because I tried Shelly 1L before and it didn't work. There are 4 Led equipments with individual transformer each.

    If this overheating problem is not solved, can you think of another solution from this manufacturer for me? Thanks