Alternatives to APU

[JimT]

Haven't looked at it yet, but right off the bat I can say that anything attached to existing mechanical systems will put an additional load on them. Even the magnets/armature idea. Ultimately the magnets are "pushing" the electrons around and just like anything else there is some resistance. So I don't see where the efficiency would come in, unless it's just the fact that you are repurposing existing components instead of adding even more parts? Ultimately either solution would be like attaching an additional alternator to the output of the engine.