Those little coin cells are what has driven much improvement in Li ion tech as they are used in medical devices like implants. Medtronic pretty much funded the first big effort made at Dalhousie to improve testing and development of Li ion cells.
I wonder if those good, small cells are marketed retail? They are proably the best you can get of any kind. 20+ year life was the development goal. Doesn't change your crank lights battery charging process, but those at least are single cells which are far simpler to manage than a pack. A simple charge cut off is very effective with a single cell. You ought to be able to discharge a single cell to zero with bad no effect. I haven't looked in a hoverboard yet, but they are small enough that quality matched cells ought to be available which would reduce pack self distruction (sometimes called self discharge). Those small, good coin cells won't self discharge unless damaged (certainly the hoverboards don't have coin cells in them). It is a neat thing about low power, miniature electronics - they can run from the voltage of a single cell. This is proving to be a stream of consiousness process so I will stop now. On Fri, Feb 5, 2016 at 11:32 AM, EVDL Administrator via EV < [email protected]> wrote: > On 5 Feb 2016 at 15:17, Peri Hartman via EV wrote: > > > I was considering buying an emergency flashlight that stays plugged in > > all the time ... I decided not to - until the Chinese develop a better > > reputation for putting a BMS in their lithium ion products. > > For a cheap gadget like that (or even a small low-range EV) a safer and > more > economical battery, though you'd have to mind disposal, would be NiCd. You > can charge NiCd at a low rate pretty much forever. > > I suppose you could also use NiMH, but I don't think they withstand that > kind of charging as well. > > Some years ago I bought some cheap made-in-Taiwan crank-dynamo flashlights > from the dollar store. I gave away a few as gifts, and kept a couple. > > I didn't notice until I got them home that the blister card boasted that > they had lithium batteries. I'm sure they had no BMS whatsoever. They > started obviously losing capacity within weeks, and within a year or two > they were storing no energy at all. They'd light up only if I kept > cranking > them. > > At least they didn't catch fire. I doubt that I could put that much energy > into them by cranking, though. > > I still have them on a shelf in the basement. Maybe one day I'll bust them > open and see if I can fit NiCd cells into them. > > David Roden - Akron, Ohio, USA > EVDL Administrator > > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > EVDL Information: http://www.evdl.org/help/ > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > Note: mail sent to "evpost" and "etpost" addresses will not > reach me. To send a private message, please obtain my > email address from the webpage http://www.evdl.org/help/ . > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Read EVAngel's EV News at http://evdl.org/evln/ > Please discuss EV drag racing at NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -- To invent, you need a good imagination and a pile of junk. Thomas A. Edison <http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html> A public-opinion poll is no substitute for thought. *Warren Buffet* Michael E. Ross (919) 585-6737 Land (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Google Phone (919) 600-2892 Cell [email protected] <[email protected]> -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20160205/c23b3492/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
