I beg to differ.
The principle, in the fundamental sense of physics, is sound - in that it is extracting demonstrable energy from a battery (or, more correctly, cell) that has fallen below some 'operational threshold'. As a simple demonstration, if you take such a cell and short it out, you will get some heating - will you not? It won't be much, nor very useful and it will not last long - but you have extracted some energy. Tell me I'm wrong. This, then, demonstrates the principle has validity. IMHO this is a point that MUST be conceded (even if quietly in one's own mind). If not, then you are just trying to sidestep the argument from the Batteriser camp - and they know that they can debate on this point because it is obvious.
It's the practical implementation that is bogus. I repeat ... the problem is with the practical implementation. There's no question some energy is there - just how to get it and how much can you get?
When I was watching Dave's video on the subject, I found myself nodding through each and every point - as the Batteriser claims and engineering in the real (practical) world clearly had a lot of distance between them. I could throw out a couple of thoughts on some of the points - but I wouldn't be saying anything Dave hasn't already covered.
But I predict that, should the Batteriser come to market, one TV advertisement will be an electronic device that stops from 'dead' batteries, where the batteries are removed, Batteriser(s) fitted and replaced with the device springing back to life. I know it's rather obvious, but if (IF?!!) they pick the right device and batteries, it will appear stunning in a 15 or even 30 second Ad.
Advertisement #2 would be to answer the critics who claim the batteries recovered enough during their period of removal (and possibly assisted by heating from studio lights and/or being handled by warm hands) would be to have two identical setups where both sets of batteries were removed for the same time and, when replaced, the Batteriser device ran to the end of the Ad while the other died in a couple of seconds.
I would like to reiterate a comment I read above - that putting the Batteriser onto a fresh battery will result in a reduction, not increase, of battery life.
But, to be fair an unbiased, we should really wait until the product is available so it could be independently assessed. Even then, when it is shown just how much hype has been used, there will still be the 'believers' - and to those people, I would like to offer one of my special bulldog clips that when placed on your spark plug leads will improve mileage, decrease emissions and clear up acne.