Re: [ee] Li Battery experts? by Russell McMahon .

Mini tutorial in applied engineering thinking: >> My current favourite is to ... Leave them in the freezer for at >> least four days. >> Take them out leave them still wrapped for over 12 hours to warm up >> Then put them back in the unit they designed for and run them flat >> before recharging them > Didn't you leave out the part about the dead fish and the proper > phase of > the moon? I used to remind my son of "standard warning number one" viz - Try to avoid trying so hard to be funny that you risk missing something important. There is anecdotal evidence from other sources who claim to have had firsthand success regenerating Li Ion batteries by this means. (Google knows). Some suggest that this may reset internal protection circuitry (for whatever reason) but this seems less likely to me. Li-Ion electrolytes typically freeze at around -40C (or -40F if in the US). (NimH and NiCd freeze at about -60C!). Most freezers will not freeze any of the above batteries so there is unlikely to be damage from crystal formation. Other damage may, of course, occur. Wrapping the cells will slow temperature changes and MAY affect the end result. Effective folk cures of all sorts often enough utilise mechanisms which are scientifically sound but little understood by the protagonists. Rejecting the possibility of such mechanisms existing, out of hand, may blind you to useful new knowledge. And, in any given situation, may not. Unless one is utterly expert at judging such situations a priori it can pay to err on the side of careful open mindedness. It may well be that in this case there is some form of chemical action triggered by this cooling, or it may be that mechanical aspects do have some effect. Maybe not, but keeping dead fish out of the freezer, and one's brain, in the meantime is probably wise. It may have been wiser to ask Peter for a description of the efficacy of his results to date and some quantitative or qualitative examples rather than attempting to demean, essentially ad hominem. RM