Does anyone know the 'do not go below' voltage at which the anode starts to break down in LiFePO4? I know it's somewhere at or below 2.0V but that's about all.
My car is parked for the winter. The other day, I went to fire it up & check on the batteries and my BMS refused to unlock it. Some investigation revealed that one of my ThunderSky cells was at 1.16V! (the rest were all at 3.345V). It may have been at that level for weeks or only hours, I really have no idea. So, after kicking myself for not disconnecting the BMS when I took the car off the road, I disconnected everything (I once before saw this particular module spontaneously turn on a balance resistor, but after several months without incident I thought I'd fixed the cause). Today I came out to remove the cell from the pack and discovered that it had recovered to 2.245V! It may have helped that temperatures have been pretty cold here in New England. I'm gently trying to nurse it back to health in an isolated area with a close eye on voltage, temperature, and amp-hours, but I'd want to understand the chemistry better before I felt comfortable putting it back in the ca r. I tried looking around the EVDL archives and the internet but couldn't turn up any numbers on the cell chemistry. What's the voltage below which actual damage occurs? Does the fact that the voltage recovered mean that it was not, in fact, over-discharged? Or does it just mean that with things disconnected the chemistry stabilized at some minimal potential? Thanks in advance, -Ben _______________________________________________ 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)
