Let's talk about a different kind of efficiency: this thread is on page one of Google.de results about your loader. It contains a link to a thread were you basically offer free stuff for positive reviews. You demonstrate a very interesting method of communication and little understanding how electricity generation works. This forum has several commercial, tech-savvy participants (manfacturing and dealers).

Good luck marketing this one away.

On the technical side: your amplifier is probably not a 4 quarant model (high VA and ~kHz with 4q does not come cheap), meaning your results will depend strongly on the amplifier. You cannot even replicate the same input current for 2 loaders. And it is not related at all to hub dynamos. Phi will be way off, no matter which amplifier you use.