Hi Jukka, Yes, don't get me wrong, I'm not arguing against having a BMS (if you remember I was talking BMS strategy with you back in 2003? at a BVS meeting in Southampton). I think I'm on borrowed time until I replace the BMS, but circumstances have produced this "experiment".
The car is used daily, discharging about 50-55% of the capacity. Sometimes shorter trips, and rarely longer trips using 80% or more. I will eventually try to balance it manually and see what sort of difference there is, or maybe the pack will die first. I don't think it can be too bad or I would already have reversed some cells on longer trips and noticed that in the total voltage. Regards Evan On Tue, Apr 22, 2014 at 3:28 PM, Jukka Järvinen <jarv...@gmail.com> wrote: > Evan, can you open a bit that 50.000 mile cycles? How shallow or deep > cycles you take? > > "Overcharge" balancing was showcased in China already in 2006 or so. It > works but kills cells. Check what yout voltages are at EOC. This would help > us to understand your special conditions and success. > > Also there are chemical additived to activate shuffling when voltage > threshold is met. This could be something CALB is using. It can add self > discharging. > > Or maybe you have been able to get good pack and BMS did good job on the > 1st years. > > Is it an agreement cells do not eventually die? Or when they do it's always > happening with noticeable increments without any chance for accident? > > When BMS fails it should render further damage impossible/unlikely to > occur. Many designs are drawing energy from cells even when off. That is > bad idea. There is alot of shit for BMS. > > If you look at the statistics how many trips are done in car without > collision and then in how many collisions there was any difference if seat > belts were on or not. Can you still argue seat belts are not smart to have? > > BMS is there to deal with many variables and with accurate measures. It's > the seat belt. > > -Jukka > > 22.4.2014 12.44 kirjoitti "Evan Tuer" <evan.t...@gmail.com>: > > > My experience differs. I have CALB 180AH blue cells in my car, which has > > covered more than 50,000 miles in about 4 years. I haven't looked at the > > pack once since installing it. I had a self-built BMS monitoring the > pack > > to start with, but it got water damaged and I never got around to fixing > > it, so for the last 2 years the pack has looked after itself (effectively > > it's been "top balanced"). > > > > > > On Mon, Apr 21, 2014 at 12:05 AM, Cruisin <crui...@live.com> wrote: > > > > > After selling CALB cells for over 5 years and using them in my own > > > conversion, I can tell you from experience the following. At least 15% > of > > > the cells will change so much in the first year the BMS will react to > > your > > > disadvantage of early charging termination and early over discharging. > A > > > one > > > year warranty that is promised is hocus. the second year will > experience > > a > > > 10% failure with no warning of a cell. This makes your car unusable. > > > Further > > > experience with other Chinese cells is no better, or worse. I now sell > > and > > > use the Nissan Leaf module that is half the price and so far no > failures > > > like the CALB. I would not ever recommend a CALB cell to any customer. > > > Those > > > that are pushing the cells like EVTV have inventory they want to unload > > > before their is no more demand for Chinese cells. My customers who have > > > converted to the Volt and Leaf cells, made by the same S Korean > > > manufacturer, are really happier with the results. No more stagnant at > > rest > > > loses that you have experienced. Look at what cells are used in the > > popular > > > plugin cars that are required to provide a 8 year warranty in > California, > > > no > > > Phosphate. CALB would be out of business if required to provide a 8 > year > > > warranty. They don't even recognize their one year warranty. You wonder > > why > > > you are having problems, wake up and smell the coffee. > > > > > > > > > > > > -- > > > View this message in context: > > > > > > http://electric-vehicle-discussion-list.413529.n4.nabble.com/self-discharge-of-CALB-180Ah-LiFePO4-cells-tp4669067p4669069.html > > > Sent from the Electric Vehicle Discussion List mailing list archive at > > > Nabble.com. > > > _______________________________________________ > > > 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) > > > > > > > > -------------- next part -------------- > > An HTML attachment was scrubbed... > > URL: < > > > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140422/72edaa01/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) > > > > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140422/717f4241/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) > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140422/bcb7f3a2/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)
