Calculate hⓂs from seconds

1

Hi Forum :wink:

From a Victrondevice i get the runtime in seconds. It would be better, to have h:m:s

I’ve build with messages in this Forum:

     - name: 'BatterieRestzeitSek'
      unit_of_measurement: "Sek."
      slave: 237
      address: 303
      data_type: uint16
      scale: 100
      precision: 0

  - platform: template
    sensors:
     BatterieRestzeit:
      friendly_name: "Batterie Restzeit"    
      value_template: "{{ states('sensor.batterierestzeitsek') | uint16 | timestamp_custom('%H:%M:%S', 0) }}"

But I get the error 
"'str' object has no attribute 'get'

What is wrong?
Thanks and best regards