Battery Desulfation
judging by testimonials from both private and commercial sources,the device is highly effective at keeping batteries at peak performance and restoring old batteries that no longer charge.its about $50 US worth of parts,or about $50 dollars for a commercially made model which is about the cost of a new battery!there must be some dark conspiracy by the battery/automaker alliance to keep these out of cars,because they obviously work just based on how many people are building their own
i dunno,was that off topic?