I agree with that. Sent from my iPad
> On Jun 18, 2015, at 10:12 PM, Michael Ross via EV <ev@lists.evdl.org> wrote: > > A question for Paul DOve, > > Whence came your evidence of self discharging in Li ion cells? > > I have the other impression entirely - that there is no mechanism by which > self discharge is even possible. > > If cells are mismatched in a pack there can be an accumulation of drift > relative to other cells in a pack (which can cause problems), parallele > cells will equilibrate among themselves (why you want them to be closely > matched) BMS and other electrical/electronic equipment can produce a > parasitic load across a pack, but a charged cell sitting alone on a shelf > does not lose charge. It's capacity can decrease so that subsequent > performance is less good, but there is no self discharge. > > Mike > > On Thu, Jun 18, 2015 at 10:59 PM, Cor van de Water via EV <ev@lists.evdl.org >> wrote: > >> Paul, >> >> I presume you never ride in a car, because Ford's Pinto was a bomb on >> wheels and unsafe at any speed. >> >> Your line of reasoning does not warrant a serious response and I have >> given many reasons why a BMS >> is a good thing - I like to discuss based on arguments and data, not on >> lore and incidents. >> >> BTW, last I heard the root cause of the dreamliner fires is still unknown, >> there is suspicion >> about the quality of the batteries, similar to what caused laptop >> batteries to catch fire >> due to impurities embedded in the cells and trigger thermal runaway. >> I have helped to investigate a fire in a converted EV with Lithium-Ion >> prismatic cells >> that I suspect (but it was never conclusively proven) was caused by >> manufacturing defects. >> There was no BMS on that pack and it was not being charged, still it >> caught fire just sitting. >> One thing that I found was that what appeared to be a hotspot also showed >> severely deformed >> (folded crooked as if they were rammed into the prismatic case) cell >> plates (the original >> pouches that are contained in a bundle inside the prismatic cell) in one >> of the cells. >> But you can't say "they used a BMS so that caused the fire". If you have a >> source >> that proves that it was in fact the BMS causing the fire then I would be >> interested in a link. >> Here is what I have: >> >> http://arstechnica.com/business/2013/02/investigation-reveals-cause-of-battery-fire-on-boeing-787-dreamliner/ >> https://en.wikipedia.org/wiki/Boeing_787_Dreamliner_battery_problems >> >> http://www.ifsecglobal.com/dreamliner-lithium-battery-fire-cause-still-unknown/ >> >> Regards, >> >> Cor van de Water >> Chief Scientist >> Proxim Wireless >> >> office +1 408 383 7626 Skype: cor_van_de_water >> XoIP +31 87 784 1130 private: cvandewater.info >> www.proxim.com >> >> >> This email message (including any attachments) contains confidential and >> proprietary information of Proxim Wireless Corporation. If you received >> this message in error, please delete it and notify the sender. Any >> unauthorized use, disclosure, distribution, or copying of any part of this >> message is prohibited. >> >> >> -----Original Message----- >> From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Paul Dove via EV >> Sent: Thursday, June 18, 2015 6:31 PM >> To: EVDL Administrator; Electric Vehicle Discussion List >> Subject: Re: [EVDL] Bicycle battery >> >> Even Boeing burned up dream liners with a BMS. >> >> Got any other argument besides everyone is doing it? >> >> >> >> Sent from my iPad >> >>>> On Jun 18, 2015, at 2:02 PM, EVDL Administrator via EV < >>> ev@lists.evdl.org> wrote: >>> >>>> On 18 Jun 2015 at 11:43, Cor van de Water via EV wrote: >>>> >>>> That pack is very nicely top-balanced and I expect that many more >>>> BMSs that you are not even aware of in daily appliances such as power >>>> tools will all top-balance. >>> >>> One more time. There is a really good reason that the only place you >>> find aversion to BMSes is among EV hobbyists. >>> >>> Real world electronics manufacturers -- the ones who build millions of >>> laptops, mobile phones, power tools and yes, commercial EVs -- know >>> that you don't sell a product with a lithium battery unless it has >>> ample smarts to protect the battery, the user, and the manufacturer. >>> >>> Trust me, these guys have bean counters looking over their shoulders. >>> They wouldn't be using BMSes if they weren't necessary. BMSes protect >>> the battery from early failure, the user from hazard to life and limb, >>> and the manufacturer from the lawyers! >>> >>> 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 >>> For EV drag racing discussion, please use NEDRA >>> (http://groups.yahoo.com/group/NEDRA) >> _______________________________________________ >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >> For EV drag racing discussion, please use NEDRA ( >> http://groups.yahoo.com/group/NEDRA) >> >> _______________________________________________ >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >> For EV drag racing discussion, please use 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) 631-1451 Cell > > michael.e.r...@gmail.com > <michael.e.r...@gmail.com> > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150618/d4c725e6/attachment.htm> > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA > (http://groups.yahoo.com/group/NEDRA) > _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
