I don't think there is any issue charging at 32°F. At any rate, you can even charge at -4°F (-20°C) if you reduce the charge rate. What the rate should be for a particular battery, I don't know. Pretty low like maybe 0.1C. I am not saying to risk this.
This is all kind of sketchy because there are a lot of papers on it, but they are written about this and that cell type, this and that electrolyte. It is, as they say, a problem of "kinetics." When it is cold the electrolyte may be more viscous than ideal (there are thin electrolytes used, but we have little knowledge of what our Chinese benefactors are up to). The ions have a hard time getting through the interface between the anode and the electrolyte. If the electromotive force is great then the Li simply pile up before reaching the anode (plating). This physically blocks the passage of the ions. This is reversible, but other things go wrong that degrade the performance. So you want to avoid it to be sure. Heaters are a great way to get around it. If anyone is curious, I can share this, email me your email address Multi-Scale Characterization Studies of Aged Li-Ion Large Format Cells for Improved Performance: An Overview Shrikant C. Nagpure,a,* Bharat Bhushan,a,z and S. S. Babub On Thu, Jan 30, 2014 at 12:16 PM, Rick Beebe <[email protected]> wrote: > Blue SE or Gray CA cells? I think the CA's are a substantial improvement. > > Keegan at the US CALB warehouse is fairly responsive. Or if you bought > them from one of the US resellers I'd hope they would go to bat for you. > > Back on topic, I am putting mine in insulated boxes with heaters in > them. Temperature controllers will turn the heat on if the cells are > below 40F and disable the charger until the batteries are warmed up to > at least 45F. The design right now calls for all of that to be powered > by shore power. I'll be monitoring the temperature to see how they fare > while parked. > > --Rick > > On 01/28/2014 05:28 PM, Cruisin wrote: > > If the cold isn't enough to worry when using the CALB 180ah cells, early > > failure is substantial with the CALB cells. I have 6 customers using > 180's > > and all have had failures of at least one cell in the first two years. > All > > use a BMS and a programmed Elcon, so I know the systems are designed > right. > > About half died while driving, BMS alerted and they shut it down. The > others > > started change in resistance values making it difficult to get a complete > > charge, or early discharge alarm from the BMS. One died 1 day after a one > > year warranty. No replacement even though CALB was told of a possible > > problem early on. I don't want to alarm anybody, and I am sure some forum > > junkie will jump in a say he has been using the cells forever without a > > problem. Probably some have, but my experience is that most will have a > > early failure. Recommendation, carry sufficient tools and HV and BMS > cables > > to be able to isolate the cell should experience this problem. Otherwise, > > you will be stuck somewhere where you don't want to be. Been there and > done. > > By the way, don't expect CALB to do anything, even during a so called > > warranty period. Support and service ended when you put them in your > donor. > > I hope I didn't hijack this thread, just wanted to pass on what I think > is a > > troublesome problem. > _______________________________________________ > 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) > > -- Put this question to yourself: should I use everyone else to attain happiness, or should I help others gain happiness? *Dalai Lama * Tell me what it is you plan to do With your one wild and precious life? Mary Oliver, "The summer day." To invent, you need a good imagination and a pile of junk. Thomas A. Edison<http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html> A public-opinion poll is no substitute for thought. *Warren Buffet* Michael E. Ross (919) 550-2430 Land (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Google Phone (919) 631-1451 Cell (919) 513-0418 Desk [email protected] <[email protected]> -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140130/296843d0/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)
