I posted in the past a spec how end charge voltage affects cycle life. There are numerous complaints from laptop owners whose battery failed just after the 1-year warranty, so most likely they never got more than 100-200 cycles (which is marginal lead-acid type performance) and it appears that laptops tend to charge their cells to 4.2-4.3V wich indeed significantly reduces their life, but giving highest capacity. Lowering the final charge voltage to 4.1 alone will sacrifice some capacity but multiply (!) the cycle life by 2 or 3. So, I am quite sure that EV manufacturers do not charge their packs to the brim and by staying well away from that bleeding edge, give their packs a much longer and much happier life - even if they use the same technology as consumer cells... (but since we have been able to read here how Tesla deviates from standard cells, we know that they get special variants and they have the volume to make demands...)
Regards, Cor van de Water Chief Scientist Proxim Wireless Corporation http://www.proxim.com Email: [email protected] Private: http://www.cvandewater.info Skype: cor_van_de_water Tel: +1 408 383 7626 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Peri Hartman Sent: Tuesday, October 08, 2013 11:53 AM To: 'Electric Vehicle Discussion List' Subject: Re: [EVDL] Range Very interesting website. I'm encouraged so far. The best chart is the one that shows capacity vs miles. More like that are needed as well as cap vs time. I think the issue regarding the cells is whether those going into the Teslas are, in fact, consumer grade cells. I've seen numerous references stating that they are similar to laptop cells, but none saying that they *are* laptop cells. For example, Tesla could be buying the cells from Panasonic (or whomever) but specifying some small changes to give them better characteristics. Anyone know the real answer? The other factor is, I'm fairly certain, that Tesla has a much better BMS than most laptops. Is that significant enough by itself? Peri -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Kevin Sharpe ZCW Sent: 08 October, 2013 11:43 AM To: Electric Vehicle Discussion List Subject: Re: [EVDL] Range >I did said "most" cells. And "most" cells go into various consumer >products, that pay negligible attention to cell life. I'm sure this is >part of the reason for short life. Sorry but I'm not sure why we are discussing "various consumer products" on EVDL... I assumed your comments were related to cars... Is that incorrect? I assume you've seen the recent PIA battery study which shows how well 'commodity' cells are performing in Tesla cars; http://www.pluginamerica.org/drivers-seat/battery-study-updates Regards, Kevin Sharpe | Founder & Patron | Zero Carbon World _______________________________________________ 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)
