LiFePO4 cells from ThunderSky (2005) seem to have good calendar life. Temperature seems to have more effect than cycling. Even if charged up to 100% (4.25v).
But all is changed now since the old white ones are quite different from the new yellow ones. The old white works better in cold climate. In general it should be safe to claim 10-15 year lifetime for the LiFePO4 -pack. Less for LiMn2O4 (5-9 yrs, 2 in AZ :P ). What has been nearly sad to find out is that using only 60% of LiFePO4 takes it par with NiCd-cells. NiMH far ahead. Also adding that 40% to the actual expenses. NMC cells with valid BMS have wiped the floor with LiFePO4. In EV applications where range and weight have been the main issues. In short: There's no good reason not to use 100% DOD from LiFePO4. There is a no good reason to not to charge LiMn2O4 to 100% SOC. It is essential to keep both chemistries in cool condition. Heat kills. SOC just helps a bit. -akkuJukka 2013/3/21 Rick Beebe <[email protected]>: > On 03/21/2013 07:24 AM, Mark Hanson wrote: >> >> >> I know lead is well known nut I'm still leraining about Lithium >> batteries. Recently there was a VA-Tech seminar on LiFePO4 batteries >> and Manganese-Lithiums used in the Nissan leaf. The professor said >> not to charge them above 80% or below 20%. I understand the bottom >> part, I try not to go below 80% DOD but I fully charge 2X a day to >> close to 100%. I would think that limiting a 100ah battery to 60ah >> would be a severe limitation. Why would fully charging a lithium >> battery cause degredation? > > > It doesn't, but overcharging, by even a small amount, does cause damage. And > because the line between fully charged and overcharged is so small, it's > recommended you leave a good safety margin. I guess one could argue 20% is > too much and maybe 10% is ok. I think actually going to 100% requires a very > good and very responsive BMS to make sure you never overcharge any of your > cells. > > --Rick > _______________________________________________ > 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)
