Auxiliary power unit (APU) for electric vehicles (EVS)

A method, comprising:

• providing an auxiliary power unit separate from any main battery system within an electric vehicle, the auxiliary power unit switchable between disconnected from a propulsion battery and an electric motor of the electric vehicle during normal operation of the electric vehicle and connected to the propulsion battery and the electric motor so that the auxiliary power unit powers the electric vehicle instead of the main battery system, the auxiliary power unit contained by a housing fitting within a well that is integrated into the structure of the electric vehicle and configured to hold one or more removable battery modules, the one or more removable battery modules comprising a handle for removing the at least one removable battery module from the housing, safety interlocks for hot swapping of the at least one removable battery module, and quick disconnects for electrical connectors and coolant hoses connecting the at least one removable battery module to the housing;
• configuring a charge port on the auxiliary power unit for connection to an external charger for charging of the one or more removable battery modules;
• and
• configuring at least one power outlet on the auxiliary power unit for connection to a device to be powered by the auxiliary power unit.