Methods for allocating power amongst different source spectrums, or “channels,” of a multi-channel lighting unit, and apparatus that employ such methods. Power allocation methods exploit the total light-generating capability of a lighting unit while maintaining safe operating power conditions, so as to avoid damage to the lighting unit due to excessive thermal power generation. In one example, a power allocation method ensures that a lighting unit operates at or near its maximum power handling capability for a variety of possible high brightness lighting conditions by ascribing a maximum per channel operating power equal to the maximum power handling capability of the lighting unit. The power allocation method then reapportions, if necessary, prescribed operating powers for multiple channels, in response to a given lighting command, such that the ratio of the prescribed powers remains the same but the sum of the channel operating powers does not exceed the maximum power handling capability of the lighting unit.