Writing data to Indluxdb batch node

When you want to add the device identifier then presumably you will want that as a tag rather than a field, in which case you will have to use the alternative payload format for the influx node as described in the help pane. So you will want an array containing the fields object and the tags object, something like

[
 {
  ACIN1: 220.799,
  IIN1: 3.7999,
  ...
 },
 {
  device_id: "some_identifier"
 } 
]

I think you will have to do that in a Change or Function node after the buffer parser.