That's what Boeing said but it's interesting that these batteries are used in many applications and none of them had fires. Open circuit voltage is what needs to be considered not max charge voltage,
I haven't tried this but I may just to prove a point. If you hold 4 volts on one of these cells indefinitely it will burn. Which is what they were doing. Also it was a starter battery so they didn't use much to start the APU and then is held 4 volts on the cells. Sent from my iPad > On Jun 18, 2015, at 11:47 PM, Cor van de Water via EV <ev@lists.evdl.org> > wrote: > > Paul, the 29.6V is not the max charge voltage of the pack. It is the nominal > voltage: > 8 x 3.7V (these were Cobalt cells) = 29.6V > So the max 32V on the bus is actually only 4V per cell and that means that > they keep those cells > below max charge voltage of 4.2V > So, it was not possible that the battery was over-charged, unless a cell > shorted and the 32V > was applied to 7 cells in series instead of 8! > > Cor van de Water > Chief Scientist > Proxim Wireless > > office +1 408 383 7626 Skype: cor_van_de_water > XoIP +31 87 784 1130 private: cvandewater.info > www.proxim.com > > > This email message (including any attachments) contains confidential and > proprietary information of Proxim Wireless Corporation. If you received this > message in error, please delete it and notify the sender. Any unauthorized > use, disclosure, distribution, or copying of any part of this message is > prohibited. > > > -----Original Message----- > From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Paul Dove via EV > Sent: Thursday, June 18, 2015 8:21 PM > To: Cor van de Water via EV > Subject: Re: [EVDL] Bicycle battery > > We already covered how to tell is a cell has internal defects. You drain the > cell to 2.5 volts and then if the cell voltage rises it's good if it keeps > falling don't use it. I did think this up This is what NASA does. I read it > in one of their presentations. I can dig it up if you like. > > As for the Dreamliner I followed that carefully. My favorite chart that they > presented to the FAA said > - the only thing that causes lithium battery fires is overchargeing > - we can find no evidence we are over charging > - therefore the cause of the fire is unknown > > One of those statements has to be wrong. And the fire was the evidence of > overcharging. > > The open circuit voltage of their battery was 29.6 volts. The system voltage > was 32 volts. They were charging the cells the whole time the APU was running > and wondering why it burned. > > As for laptops they were overcharging as well. The paper I read the designer > claimed that leaving a small amount of current flowing or trickle charge as > they call it would not hurt lithium batteries. > > Sent from my iPad > >> On Jun 18, 2015, at 9:59 PM, Cor van de Water via EV <ev@lists.evdl.org> >> wrote: >> >> This message has no content. > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150618/c4bcfdcb/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)
