Hi Paul, I am not sure CALB should be qualified as high quality particularly if they are vintage; but it is very hard to tell, because testing methods have been inadequate for all cells until the last couple years. I would say Panasonic for sure are high qualify at least relative to the universe of Li ion. Maybe LG? They seem to be trying hard and working smart.
Little cylindrical cells have form factor advantages. The large prismatics can't take the volumetric changes as well over time. It is mechanical issues that are the primary cause of grief with respect to degradation over time, not the basic chemistry and configuration itself. Clearly electrolyte composition is important, but this is a newer frontier. Good testing that provides useful results in a relatively short time will help everyone. Mike On Sun, Nov 8, 2015 at 2:13 PM, paul dove <[email protected]> wrote: > I didn't address the self-discharge on purpose. People will believe what > they want. > > However, I had a pack of Calb 60Ah cells in my garage that I had drained > to bottom balance. I had forgotten about them and it had been over a year > since I did this. We were having the conversation about self discharge on > this web site and I got worried they were correct after I posted the > article on here talking about self discharge in Li Ion cells. So, I measure > the voltage on all the cells and found a couple that were down to 1.8 volts > and then I thought they were correct. > > i took the cells and charged them. It was weird the voltage went allover > the place but I didn't give up. I discharged them and charged them and the > first time it had 25 Ah. the second time 45Ah and so I cycled them about 5 > times and every cell came up to full capacity. I know because I have the > capacity sheet from CALB and the all have serial numbers. > > This inadvertent experiment confirmed the findings of the paper that I > read. Saying that self discharge is manifested in a temporary loss of > capacity that can be recovered by cycling the cells. > > Now, not all the cells exhibited this behavior. There were three cells out > of a hundred that did this. The rest of them were fine. > > ------------------------------ > *From:* Michael Ross <[email protected]> > *To:* paul dove <[email protected]>; Electric Vehicle Discussion List < > [email protected]> > *Sent:* Sunday, November 8, 2015 12:18 PM > > *Subject:* Re: [EVDL] Rickard's EVTV let the smoke out> overcharged pack > fire blew up > > I think the self discharge complaint is growing less all the time - with > good quality cells. But really large packs beg prudence. A golf cart > packs, like Jack sells which will be operated by non EV types, gets real > benefit from his bottom balancing and sealing. The little 10AH 48V packs > used in light EVs and bikes are a analogous - small, operated by the > unwashed. > > Whatever is done, a really dependable charge cut off function must be part > of any system. > > Our ability to evaluate cell quality, and BMS quality and function is > still suspect (particularly for the cash strapped DIYer; as opposed to a > large company with real money to command action) so I expect this argument > to continue, and it should. > > > > On Sun, Nov 8, 2015 at 1:03 PM, paul dove via EV <[email protected]> > wrote: > > There is no evidence thus far to support that theory. > It could have been a pack he uses to power his bench or one he was > charging to put in a car. > He does all sorts of crazy experiments like test the sag while pulling > 1000 amps. > From the article it didn't sound like it was in a car. > > From: Bill Dube via EV <[email protected]> > To: EVDL Administrator <[email protected]>; Electric Vehicle Discussion > List <[email protected]> > Sent: Sunday, November 8, 2015 11:51 AM > Subject: Re: [EVDL] Rickard's EVTV let the smoke out> overcharged pack > fire blew up > > This fellow is the flag bearer for the small anti-BMS movement. > A pack fire (in this instance a pack explosion) was predictable and > unfortunately inevitable. I'm glad that no one was injured. > > Pack fires do rarely occur even under ideal circumstances, ("The world > is an imperfect place, screws fall out") but this pack fire was simply a > matter of time, like a ticking bomb simply waiting to go off. As I > understand it, he has had less dramatic pack fires before. > > It would be a positive outcome of this tragic incident if this were to > change a few minds in this minority anti-BMS crowd on the need for a > BMS. Unfortunately, the anti-BMS crowd doesn't understand, (or choose to > ignore the advice of the countless experts that /do/ understand,) that > variable self discharge exists in li-ion cells. It is a very real > problem in maintaining battery balance in a high-voltage battery pack. > This is why folks go through the trouble and expense of qualifying and > buying a BMS for each and every high-voltage li-ion battery pack. > > Bill Dube' > > > > On 11/8/2015 3:45 AM, EVDL Administrator via EV wrote: > > Not to cause controversy, but do I recall right that Jack Rickard is one > of > > the guys who've said that lithium batteries without BMSes never catch > fire? > > Or was that someone else? > > > > Certainly that's a claim I've heard, on the EVDL and elsewhere. > > > > 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 > <http://groups.yahoo.com/group/NEDRA?soc_src=mail&soc_trk=ma>) > > > > > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20151108/acefeedc/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 > <http://groups.yahoo.com/group/NEDRA?soc_src=mail&soc_trk=ma>) > > > > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20151108/eeb6c260/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 > <http://groups.yahoo.com/group/NEDRA?soc_src=mail&soc_trk=ma>) > > > > > -- > 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]> > > > > > -- 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... 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