David, How much do your Lithium batteries heat up when charging? Do you have measurements? From what I have heard and seen, the fact that Lithium is typically charged between 20 and 80% for max life, there is no significant heating in this range of SoC during charging. I am not sure about the heat produced above 80% but I suspect that the only significant heating is from bypass regulators in the BMS and they only come on *after* the cell is done charging, so it does not help to avoid damage from occuring when charging in the cold. I do have cells that heat up during charging, but those are not Lithium.
Cor van de Water Chief Scientist Proxim Wireless Corporation http://www.proxim.com Email: [email protected] Private: http://www.cvandewater.info Skype: cor_van_de_water Tel: +1 408 383 7626 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of David Murphy Sent: Monday, January 06, 2014 3:18 PM To: Electric Vehicle Discussion List Subject: Re: [EVDL] Charging Lithium Below Freezing Well, I wouldn't interpret this as you can't use them. This is a data point that says (1) charge current needs to lowered at lower temps (2) that the manufacturer won't guarantee the cycle life if you charge below 0 degrees C. So perhaps one should use a heater below 0C. And charge at lower current in cold weather. The batteries will heat up while charging as well, which should help David Sent from my iPhone > On Jan 6, 2014, at 1:02 PM, Mark Hanson <[email protected]> wrote: > > Message: 13 > Date: Mon, 6 Jan 2014 11:13:52 -0800 > From: David Murphy <[email protected]> > So does that mean you can't use Lithium below 0C / 32F ? That doesn't make any sense for those who live in the northern latitudes & Canada. I charge about .1C anyway (13 amps on CALB 130ah batts). I've charged at 20F but tonight it'll be 0F in VA. What about folks in Minnisota like Lee? I guess they use battery heaters but I thought most chemistries you could charge cold just take a bit longer due to higher internal resistance.Best Regards,Mark > To: Electric Vehicle Discussion List <[email protected]> > Subject: Re: [EVDL] Charging Lithium below freezing, should I drive my > gas car? > Message-ID: > <cahtzjazxhv3i2+ugau3ms_tyrnddvywyf2-dwjkt846nd7c...@mail.gmail.com> > Content-Type: text/plain; charset="iso-8859-1" > > So the cells I am talking about are referred to as Lithium Ion Polymer, not > sure if that is the same chemistry... > The specs for these type of cells define three temperature ranges for > charging. (cell temp, of course, not ambient) > from 0C to 10C > 0.1C max Constant Current (CC) to 4.2V, 4.2C Constant Voltage (CV) to > 0.05Cmin cut-off > 10C to 23C > 0.5 max CC to 4.0V, 0.2C CC to 4.2V, 4.2V CV to 0.05C > 23C to 45C > 0.5C CC to 4.2V, 4.2V CV to 0.05C > > for discharge, the oeprating temp is -20C to 60C > > Hope that's helpful... > > david > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140106/bfe0 8bc2/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) > _______________________________________________ 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) _______________________________________________ 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)
