Put a decimal in value from Modbus

I can get the correct voltage data into HA from my PLC, however I cannot figure out how to put a decimal into the value into the correct location. PLC value is 12800 HA is 12800 if I use precision: 3 it puts a decimal to the right 3 places. I need to move it to the left so it reads 12.800. I have searched internet and tried for hours. Any help is greatly appreciated! Here is my section of code:

    - name: "Battery Voltage"
      address: 0778
      scan_interval: 2
      input_type: holding
      precision: 3
      unit_of_measurement: v
    scale: 0.001

In my case the output would be 13.0 (no digits behind commas). Is the a global setting or what do I wrong?