A generator set. In one embodiment, the generator set includes an internal combustion engine, a DC generator, one or more battery cells, and an inverter. The DC generator is coupled to the engine and produces direct current (“DC”) electricity. The battery cells discharge stored DC electricity and can be recharged using DC electricity from the DC generator. The inverter is electrically connected to the DC generator and to the battery cells. The inverter converts DC electricity produced by the DC generator and DC electricity discharged from the one or more battery cells to alternating current (“AC”) electricity. The AC electricity is available for use by a load.