Well does that LK3 device publish an

[maiden basin]

nothing like that is mentioned on their website https://docs.tinycontrol.pl/en/lk3/pages/mqtt-client/?referrer=lk3#mqtt_commands

[regal grail]

Unsurprising really

https://www.home-assistant.io/integrations/mqtt#mqtt-discovery

[maiden basin]

i can see those messages coming! https://www.screenpresso.com/=n6T6c

that number 99.99 represents battery load in %. if i understand it right, i should add these lines into config.yaml:

mqtt:
sensor:
- state_topic: "LK3/m3"

and restart the server. is that correct?

[regal grail]

Don't restart the server, try just https://www.home-assistant.io/docs/configuration/#reloading-changes first

Then if that doesn't cover it, restart Home Assistant - not the server

Of course, you probably want to do sensible things like give your sensor a name, and a unit of measurement etc

[maiden basin]

the reload of changes will probably not work since it seems there were some changes to templates and utility_meter few months back. i am getting errors when i validate the config.

[regal grail]

Well, you should fix that

Having known problems with your config is great way of getting things to not work

[maiden basin]

i would love to. need to spend more time on this

[regal grail]

Leaving known problems with your config in.... "unwise"

Right, but not fixing them may stop this from working

Take the time to fix things before you try to set up new things and you'll actually save time

[maiden basin]

i am aware of that. i am really frustrated that Energy tab does not show anything for quite a long time

i have it on my to do list

[regal grail]

Ok... well... then good luck, because it sounds like you need it

[maiden basin]

does this look good to you?

mqtt:
sensor:
- state_topic: "LK3/m3"
unit_of_measurement: %

- state_topic: "LK3/m1"
   unit_of_measurement: V

- state_topic: "LK3/m2"
   unit_of_measurement: V

well i replaced % with pct