Hi Mike etc,
The cell voltage longevity data is from the previous email I sent to the list regarding www.batteryuniversity.com data (can’t remember right now, wrote down the article number when I sent it from my iPhone). I was questioning the 2013 Leaf manual assertion that charging the battery to 80% resulted in a longer lasting battery, looking for *real* data (since they dropped the requirement in 2014 – apparently for marketing MPC reasons). But the Battery University data says that charging to a slightly lower final cell voltage of 4.05V is 1200-2000 cycles (*much* more than 4.1V = 600-1000 cycles, 4.2V = 300-500 cycles) and since the Leaf actively balances, not just at 100% it seems that the Nissan assertion that *80% charging* (especially when doing short distances like my son does daily at 16 miles) makes sense. Cor I think mentioned that at “100%” for the Leaf is 4.12V so that’s in the 600-1000 cycles. Si *if* you believe the data charging at 80% (2K cycles) will result in a battery that will last *twice* as long as one that is charged to 100% (1K cycles). (May not be exactly twice since the 80% cycles are, well 80%). Have a renewable energy day, Mark Mark E. Hanson 184 Vista Lane Fincastle, VA 24090 540-473-1248 phone & FAX, 540-816-0812 cell REEVA: community service RE & EV project club Website: www.REEVAdiy.org (See Project Gallery) UL Certified PV Installer My RE&EV Circuits: www.EVDL.org/lib/mh From: Michael Ross [mailto:michael.e.r...@gmail.com] Sent: Wednesday, October 05, 2016 7:16 PM To: Mark Hanson; Electric Vehicle Discussion List Subject: Re: [EVDL] Best charge rate for longevity Can you share link to the webpage you are referencing? I don't believe you can measure voltage and calculate such a thing. Voltage is simply not a very good way to determine SOC. Charging to 100% is not going to cause a "thermal event." High temperatures caused by large discharge (which lowers the SOC) is one way to get them hot. Some chemistries (early Leaf for example) deteriorate at an accelerated rate when charged to a high SOC, AND exposed to too high an ambient temperature - such as gridlock in Phoenix where they experienced poor life performance of early Leafs. Pay attention to the "AND." 100% SOC or temperature alone may not damage a li ion cell. But so much of thise depends on thigs we don't know, can't know, are told incorrectly, and so on. You pretty much should use whatever procedure the EV manufacturer says to use for charging a pack. Don't try to second guess them. You are unlikely to accumulate the necessary information to do it in a more effective and rational way. In numerous cases with older BEVs the manufacturers are working from their own poorly conceived testing and basic understanding. Presumably newer BEVs are better, but who knows. I trust Tesla, but not sure about anyone else. On Wed, Oct 5, 2016 at 4:34 PM, Mark Hanson via EV <ev@lists.evdl.org> wrote: Thanks folks So if the Leaf charges at the 100% setting to 4.12vpc and 80% to 4.05vpc and battery university says max life of 2k cycles is at 4.00vpc then I should change my charge cut off at 80% for daily short trips of 15 miles typical. Plus since balancing occurs all the time there's no need to charge at 100% except for long trips Best regards Mark Sent from my iPhone _______________________________________________ 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. <http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html> Thomas A. Edison A public-opinion poll is no substitute for thought. Warren Buffet Michael E. Ross (919) 585-6737 Land <https://www.google.com/voice/b/0?pli=1#phones> (919) 576-0824 Mobile and Google Phone michael.e.r...@gmail.com -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20161005/280410e7/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)
