Patent ID: 7259469

Claim:
A truck, comprising: a personnel compartment; a main engine and a main battery; an external auxiliary compartment connected to an exterior portion of the truck; and an auxiliary power unit assembly positioned in the external auxiliary compartment of the truck, the auxiliary power unit including: an auxiliary engine, an auxiliary alternator positioned adjacent to and powered by the auxiliary engine, to provide DC electric power, the auxiliary alternator being electrically connected with the main battery to charge the main battery while the main engine is off, an inverter electrically connected to the auxiliary alternator to convert the DC electric power from the auxiliary alternator to AC electric power for powering at least one AC electrical component, and an auxiliary voltage regulator electrically connected to the auxiliary alternator to control voltage and amperage generated by the auxiliary alternator, the auxiliary voltage regulator-configured to sense voltage of the main battery to selectively disable the inverter if the voltage of the main battery drops below a selected level, and to sense RPM of the auxiliary engine during start-up to allow auxiliary engine speed to obtain a minimum selected speed prior to enabling application of an electrical load to the auxiliary alternator.