MAXcube platform

I am using the MAX cube platform and it works more or less stable now. If I look in the python code I see that apart form current and target temperature it also defines other properties like valve_postion, battery, etc I have tried to create sensors for these like:

    friendly_name: 'Kitchen Fat Radiator battery'
    value_template: "{{ state_attr('climate.kitchen_fat_radiator', 'battery') }}"
    unit_of_measurement: '%'

but they stay at the initial value ‘none’ are they not updated?