Interesting video, I didn't expect that a battery would be only discharged by a few percents with a short for a minute.

Recently I found another video (I think he did a Kickstarter project and I read about it somewhere here in the forum, but can't find it anymore) :

The video is really boring, you should not watch it, but the interesting part is from minute 30 to minute 37: He measured with a scope the phase angle of the voltage and the current at the input side of his device, and it was 10.75 V, 1.466 A and 78°, so a power of 10.75 V * 1.466 A * cos(78)=3.277 W. Then he measured the voltage and current at the output (a resistor load) and it was 5.228 W. Obviously it doesn't work, otherwise he would have done the only thing to prove such claims, connecting the output to the input and then the resistors should still get hot, but where is the error in the calculation or the measurements?