Join Date: Jun 2018
Location: NW italian Alps
From MY2018 (standard and Adventure Sports) the OEM aux socket is connected directly in the main loom and not to the option port behind the instrument panel (which had a 2A fuse inline to the socket and is a nightmare to replace in case). Therefore the MY2018 12v OEM aux socket is protected by the 10A OPT fuse in the box under the seat.
I think you will not have any problem using the charger you described in a MY2018- Standard or Adventure AT.