Customize battery (device_class)

Hi. Got some sensor readings from a couple of batteries and I defined them as follow:

# sensor.yaml file
- platform: modbus
  registers:
    - name: Wago_DC1
      slave: 1
      register: 0
      scale: .000915751
      precision: 1
      unit_of_measurement: V

#customize.yaml file
sensor.wago_dc1:
  friendly_name: Batteri 1
  device_class: battery

Shows up fine i UI, but since the battery is 12V is shows up with the “almost empty” icon.
batteri1
Guess it would be full if I had 100V.
Id like to customize this somehow so I get the full battery icon when I have 13V instead.
Not sure if possible and it that case, how?

The battery device class assumes that the value is the percentage of the charge. You could simply customize the icon to be mdi:battery.

You could use the template sensor and change the icon based on charged.
the template sensor has an icon template

Or use the scale: key to factor it to % instead of V, though voltage is a poor indication of % charge for lithium batteries in particular due to their flat discharge curve. Lead-acid is not as bad.