People are hard-wired for anecdotal experience to reign supreme. Lead vs Lithium, BMS vs. no BMS, Ford vs. Chevy, Coiled vs. daisy chain, skinny vs. wide (tires or asses, does it matter?), blonde vs. brunette, nerd vs. jock, need I go on?
Any wise person can recognize there are advantages to all, each and every. And, yes, they all have issues. But you have to choose one, don't you? Blue CALBs placed at Pikes Peak. Leaf Battery?? DNF... Respect what works. On Sun, Apr 20, 2014 at 4:04 PM, Cor van de Water <[email protected]> wrote: > Since about 6 months I have been testing the self-discharge of > a bunch of blue CALB LiFePO4 cells. > The good news is that after half a year of sitting, their > average voltage has changed from the (parallel) charge voltage > of 3.00V (meaning that they were charged to approx 10% SoC to > allow me to see how quickly they would fall off again, as the > voltage changes are larger to wards the extreme ends of the > charging curve) (after which I disconnected them to measure the > individual self-discharge of just each cells by themselves by > occasionally connecting a DVM to check and record voltage by hand) > to a self-discharged voltage of between 2.78 and 2.86V. > The current highest cell has the lowest self-discharge, losing > only about 80mV in that half year, while the fastest self-discharging > cell has lost almost double that voltage - 140mV > Note that this is not from the original 3.00V but from their state a > few weeks after I disconnected them, when I started recording voltages. > So, while the sitting of a cell over a half year (in winter) > apparently removes less than 10% of the charge, there definitely is > a marked difference in self-discharge between cells of almost 100% > higher discharge for the worst cell than the best cell in this sample > set of 16 cells. > > I thought this might be of interest to some here. > > Cor van de Water > Chief Scientist > Proxim Wireless Corporation http://www.proxim.com > Email: [email protected] Private: http://www.cvandewater.com > Skype: cor_van_de_water XoIP: +31877841130 > Tel: +1 408 383 7626 Tel: +91 (040)23117400 x203 > _______________________________________________ > 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) > > -- Marcus Reddish -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140421/85791fee/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)
