MQTT topic does not return a value

I appreciate help to solve this problem.
I have this code to read the topics that a raspberry sends me within the same network in the configuration.yaml file
It is not a json string, they are simple topics, with mqtt explorer I can listen to them.
But it does not return any value.
Where is the error?

sensor:
  - name: "h1voltbattery"
    unique_id: "h1voltbattery"
    state_topic: "PVControl/Hibrido1/H1BatteryVoltage"
    unit_of_measurement: "v"
    value_template: "{{ value }}"

error2-mqttexp

I think you are missing the mqtt: looking at what you posted, so HA doesnt know the sensor is mqtt.

mqtt:
  sensor:
    - name: "h1voltbattery"
      unique_id: "h1voltbattery"
      state_topic: "PVControl/Hibrido1/H1BatteryVoltage"
      unit_of_measurement: "v"
      value_template: "{{ value }}"

Once you’ve solved it (and I suspect @Dujith is right here; you’ll need to restart after adding the mqtt header), note that

value_template: "{{ value }}"

is completely unnecessary and can be removed.

Voltage should be an upper-case "V", and you can use device_class: voltage to get an appropriate icon.