An excitation current-limited power generator includes a digital interface configured to be coupled to an engine control unit (ECU), a regulator coupled configured to be coupled to an excitation current input of an alternator, the excitation current controlling current generated by the alternator, a frequency sensor configured to measuring rotation speed of the alternator, and memory storing a communicated limit received by the digital interface and a first permanent limit, the regulator configured to limit the excitation current to the lesser of the first permanent limit and the communicated limit.