Shelly EM relay control: Solved

Configuration
1

Trying to use the relay control on a Shelly EM
I can control the relay from mqtt explorer, but not from the lovelace >developer tools>mqtt
mqtt explorer is ok with
shellies/sellyem-109664/relay/0 ( payload either 1 or 0 )
I’ve tried with and without a leading forward slash “/”
in my configuration.yaml I have

 -  platform: mqtt
    name: Immersion load
    state_topic: "/shellies/shellyem-109664/relay/0" 
    command_topic: "/shellies/shellyem-109664/relay/0"
    payload_on: "1"
    payload_off: "0"

on the config checker it thrown out with

Error loading /home/odroid/.homeassistant/configuration.yaml: while parsing a block mapping
  in "/home/odroid/.homeassistant/configuration.yaml", line 1, column 1
expected <block end>, but found '<block sequence start>'
  in "/home/odroid/.homeassistant/configuration.yaml", line 236, column 2

I’m confused over line 1 as no changes there, but it seems to want to have 2 spaces leading

homeassistant:
  # Name of the location where Home Assistant is running
  name: Home
  # Location required to calculate the time the sun rises and sets
  latitude: 52.66202
  longitude: -2.46976

If I hash out the mqqt section above its happy with no leading spaces
Version reported in lovlace is 0.104.3 but I have updated but doesn’t show on lovelace.
The version showing doesn’t stop anything working so I left it as is

What I’m doing with the relay is to control a relay which shorts out a series diode ( 75A,1200v)
which is in series with the immersion element , normally a 3KW load, but with the series diode the load is 1.5KW. Used on my solarPV system so power generated is less than 3KW I can switch the load level, works fine on a resistive load.

what am I screwing up with the config please

2

Sorry
I did my normal trick with a space in the wrong place

The scripts , config and automation are checking OK BUT not talking to the EM relay, it reads OK from the sensors.
configuration.yaml:-

# from sensor section
  - platform: mqtt
    name: "Solar Energy"
    state_topic: "shellies/shellyem-109664/emeter/0/energy"
    value_template: "{{ value|float / 60000 }}" # Fix for Watt-minutes
    qos: 1
    unit_of_measurement: "kWh"
#  icon: mdi:chart-bar
  
  - platform: mqtt
    name: "Solar Power"
    state_topic: "shellies/shellyem-109664/emeter/0/power"
    qos: 1
    unit_of_measurement: "W"

#from switch section
  - platform: mqtt
    name: Immersion load
    state_topic: "/shellies/shellyem-109664/relay/0" 
    command_topic: "/shellies/shellyem-109664/relay/0"
    payload_on: "ON"
    payload_off: "OFF"

A bit more

after restarting a few times I can control from dev tools>mqtt
and the following in configuration now seems OK

  - platform: mqtt
    name: Immersion load
    state_topic: "shellies/shellyem-109664/relay/0" 
    command_topic: "shellies/shellyem-109664/relay/0"
    payload_on: "on"
    payload_off: "off"

BUT, I added a switch to lovelace so I can toggle switch.immersion_load
which sorta work
and watching mqtt explorer I can see the relay changing for on to off and viceversa

HOWEVER, if I turn it on, it turns off all by itself within 10 seconds, mqtt explorer shows the same.
If I set the payload to “on” from dev tools>mqtt it turns off after 15 seconds

I checked on the Shelly GUI for the EM, http , and the switch was set to OFF

So I set the set from the gui to ON
turned the switch off from dev tools>mqtt , and within 20 seconds the damn thing turns back on
The the moment the manual control switch on the shelly GUI for the EM takes priority .

After a lot more playing
/relay/1 can be set and unset without problems and it stays in the position set.
However it does not control the actual relay.
Two possibilities:

  1. Shelly fix their software , I’ve upgraded to the latest and it still behaves the same.
  2. Investigate whether the IC which has control of relay/0 also has a physical output
    for /relay/1.
    If it has modify the drive to what is probably a mosfet switching the relay so it is OR’d with a pair of diodes, so the output which is logic high has control.

In the mean time I’ll use a spare shelly1 to switch my external relay

3

I found what Shelly have done by routing through the API and playing with some http commands.
You no longer switch the relay , you have to switch the command to the relay
Shelly have not updated their documentation to indicate this, its applicable to the EM, Shelly1 and I suspect everything else that is switchable with the latest firmware.

  - platform: mqtt
    name: Shelly EM
    state_topic: "shellies/shellyem-xxxxxx/relay/0" 
    command_topic: "shellies/shellyem-xxxxxx/relay/0/command"
    payload_on: "on"
    payload_off: "off"

  - platform: mqtt
    name: Shelly1
    state_topic: "shellies/shelly1-xxxxxx/relay/0" 
    command_topic: "shellies/shelly1-xxxxxx/relay/0/command"
    payload_on: "on"
    payload_off: "off"