On 30 May 2016 at 19:17, Michael Ross via EV wrote: > At 50% SOC you theoretically are seeing the nominal cell voltage. But I > warn you that you may not really know the true midpoint cell voltage. Spec > sheets are notoriously vague to incorrect on this point. Also it is not > easy tp tell anything about SOC from voltage. a tenth of a volt can be a > lot of difference in charge, a characteristic of Li-ion generally.
Years ago I read that lithium batteries should be stored at 60-70% SOC. Maybe that's allowing some room for the (usually very small) parasitic current that the BMS requires? Or for self-discharge? Or both? When I store lithum batteries, I charge them until the BMS - or, in the case of computers, the OS's meter - shows full. Then I discharge them 30-40%. If possible, I then disconnect the battery from any external load. This seems to have worked fairly well so far, though I've never tested it against a control group stored some other way. One of the nice things about NiCd batteries (as opposed to lead and lithium) is that they don't really much care about their SOC in storage. You can store NiCds flat indefinitely; in fact I think some manufacturers even recommend storing single cells (not batteries) with shorting bars across them. I've often wondered if you could store NiMH the same as you do NiCd. David Roden - Akron, Ohio, USA EVDL Administrator = = = = = = = = = = = = = = = = = = = = = = = = = = = = = EVDL Information: http://www.evdl.org/help/ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Note: mail sent to "evpost" and "etpost" addresses will not reach me. To send a private message, please obtain my email address from the webpage http://www.evdl.org/help/ . = = = = = = = = = = = = = = = = = = = = = = = = = = = = = _______________________________________________ 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)
