Add support for devices that don't report battery levels in percentages

[almirus]

Checklist

• I have filled out the template to the best of my ability.
• This only contains 1 feature request (if you have multiple feature requests, open one feature request for each feature request).
• This issue is not a duplicate feature request of previous feature requests.

Is your feature request related to a problem? Please describe.

Currently, you can't add devices that don't provide a percentage-based battery level, like a smoke detector. It only reports battery status as: low, medium, or high.

Describe the solution you'd like

I want support for devices without percentage-based battery levels to be added. It could be possible to emulate the battery level with dummy percentages: low = 10%, medium = 50%, high = 100%.

Describe alternatives you've considered

Additional context

[zoechi]

I was just trying to accomplish something like that. I added an entity (door sensor of my Nuki smart lock) with a "battery low template", but it doesn't show up in states (Developer tools).

I have configured the battery state card with

filter:
  include:
    - name: entity_id
      value: '*_battery_plus'

To get the new battery shown I can add

    - name: entity_id
      value: '*_battery_critical'

But it gets shown with state On which isn't too helpful and a question mark as icon and also there is no secondary info about the the battery type shown like with the other batteries.

I thought I might be lacking some knownledge, but then I found this issue. So, it looks like I'm not the only one struggling with this.

[andrew-codechimp]

You can't add a battery state like this as a battery plus, but you can add a template for the boolean battery low to reflect a low battery and trigger events. I'm not sure if I'll ever add this into battery plus as there are a lot of permutations for these unusual devices.
https://andrew-codechimp.github.io/HA-Battery-Notes/#battery-low-template

[zoechi]

I had the template a bit wrong but fixing it didn't change anything.

Also using '*_battery_plus_low' for the filter doesn't help.

So there is no way to get the battery type shown as secondary info for such batteries?

[andrew-codechimp]

Unfortunately not, the template only affects the binary sensor, not the battery plus one, so it's no use in dashboards the way you are wanting to use it.
If I can ever think of a nice way of handling this I will, but it's got to be flexible and easy to configure/understand for me to add it.

[zoechi]

I understand.
Thanks a lot anyway for this cool integration 🚀

[almirus]

I'm not sure if I'll ever add this into battery plus as there are a lot of permutations for these unusual devices.

The algorithm could be as follows:

1. Allow adding all devices (at your own risk): The integration will serve as a source of information about the type of batteries used and when they were last replaced.

2. Add all devices containing the attribute .*battery.* and analyze: If it's a number, process it as a percentage. If it's a string, process it as low, medium, or high.

3. Add devices with a user-defined template for extracting battery percentage: Users can specify a custom template to extract the battery level from devices that don't provide standard percentages.

[andrew-codechimp]

Thanks for your suggestion but there are also batteries with voltages, ones with Normal or Low and also ones that just display a binary low natively, that we'd also want to have as a sudo percentage.
I'm not forgetting about this, but as stated there are a lot of things to consider and also make it easy to use.

[andrew-codechimp]

So I've been experimenting with ideas around this and it turns out without any code changes you can create a Template Helper and have Battery Notes pick it up and create a Battery+ sensor.

I've documented how to do this here, feedback appreciated if you have issues.

https://andrew-codechimp.github.io/HA-Battery-Notes/entities/#adding-a-battery-percentage

[almirus]

@andrew-codechimp success! thank you!