2A is the max draw when the transceiver is at full power, in your short-range application it won't even hit 1A. The vehicle ignition position should be at ACC On to be able to power-up the socket. Go to your nearest Radioshack to buy the crown-plug to cig-light adapter. Bring the router with you because not all crown-plugs are created equal, they have innder diameter differences. Re input voltage, most soho internal power regulator can handle the 11-16V range.

Imo at that price it becomes a very tempting buy even with its' flaws.
2021 Nissan Leaf