*"I was expecting similar or better performance on the Leaf battery."*
As far as I can tell that was an unwarranted assumption. If anything is true, it is certain that LFP are an outlier in behavior to the other chemistries that have Li metal oxide positive electrodes. I heard Jack Rickard claim he knows what the chemistry of t a Leaf cells are, but it wasn't from a spec sheet. Does anyone know for certain? I heard a professor working on cell design claim Tesla was using LFP, but is clearly no long correct, if it ever was. Misinformation abounds. Then you add in we know nothing of the details of cell construction - ** how is the graphite was made and handled? ** how is the electrolyte and its additives were compounded? ** What is the quality of connection between the conductors and the terminal connections? In the pack we don't know - ** how well the cells are connected and by what? ** are they cooled? ** how well does it work? ** how does the BMS work? ** how should it work? In the field we don't have a good idea how driving habits and climate impact different cells. And so on. This is a tall stack of don't knows. Then we try to do these comparisons in the least accurate way - ** with very imprecise instrumentation (LFP is the worst for a flat voltage/capacity curve) ** during uncontrolled use, ** in a long term performance evaluation ** where all the unknown contributing factors have a chance to accumulate idiosyncratically.. We take our pattern seeking mind with all its cognitive biases an start drawing inferences from coincidences and feelings. It is no wonder we are mostly confused about it. On Fri, Mar 27, 2015 at 7:03 AM, Willie2 via EV <ev@lists.evdl.org> wrote: > On 03/27/2015 12:50 AM, EVDL Administrator via EV wrote: > >> On 26 Mar 2015 at 19:57, Ben Goren via EV wrote: >> >> That's the idea behind my suggestion of a "remaining (usable) kWh" >>> gauge ... >>> >> Sounds good to me. >> >> Solectria had a simple answer to this. They gave you a straightforward >> amp- >> hour meter. As you drove, it counted up; as you charged, it counted down. >> When the charger shut off, it zeroed itself. >> >> After a few years driving my conversion with a TBS amp-hour counter, I > was expecting something as straightforward in my Leaf. I don't know how > modern factory EVs estimate the battery capacity but on the conversion, I > felt the need to do the occasional "capacity test". I would fully charge > and balance and then pull it down until some cells started going low. I > reported the tests here amid quite a bit of scepticism. My 260ah > ThunderSky LFP cells started off giving me about 300ah. They smoothly > declined over the years and are currently about 230ah. I was expecting > similar or better performance on the Leaf battery. I was sorely > disappointed. The conversion went about 50 k miles over about 7 years and > suffered about 20% capacity loss from new (a bit more than 10% from > advertised). While the Leaf lost 30+% in two years and 20k miles. Both > batteries endured the horribly hot summer (about 100 days above 100 deg) > that so damaged the Leaf battery. The ThunderSkys seemed unaffected. > _______________________________________________ > 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/20150327/44df66bf/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)
