So if your using battery notes then you will select Exclude Hidden Battery Sensors. That was one of the reasons it was added. Then in your configuration.yaml add
Your text helper is Low Battery Notifications. To find all your helpers you have created go to Settings > Devices & Services > Helpers (tab at the top). There you will see your Low Battery Notifications text helper. Click on it and then click the cog wheel. Now you see the options.
The thing to note is once you created this text helper it will be empty and there will be no text formatted in the correct way. In order to create some text you have to run the automation just once so it will populate the text helper. Then when you add it into the dashboard everything will work.
I don’t have the battery sensors hidden by choice for battery_notes configuration. I use both device and battery notes sensors together as sometimes there are inaccuracies/issues between the two. I guess I’d have to live with it or make changes, thanks nonetheless.
I just tried to implement this blueprint last night (Home Assistant OS, Core 2025.10.3, Supervisor 2025.10.0) and got the same error (UndefinedError: list object has no element 1) from the Markdown card.
Here’s my yaml following your response to thomas15.