On Sun, Dec 25, 2016 at 1:51 AM, V G wrote: > Hi all, > > I'm thinking of ordering 10 of these 10Ah NiFe cells just to experiment > with them and eventually use them in a double-conversion UPS: http://www. > ironcorebatteries.com.au/page2.php > > The most important factor to me is reliability and calendar life. I want > to know that I can cycle these cells moderately and they'll still be > working 30 years later. > > Is this a reputable seller? Does anyone here have experience with NiFe > cells? > > Somewhat related: I just found some 15 year old 700mAh NiCd AA cells that > are all still reading 700mAh after cycling a few times - amazing. > I also realize the next best thing is likely LiFePo4 doped with yttrium to improve low temperature performance. These cells seem to have a very high cycle life when deep discharged, but I'm worried about their calendar life and what factors influence degradation over time. Temperature must be a factor, but I never stress my cells with anything higher than a 1C discharge. LCO, LMO, NMC cells all seem to have accelerated degradation at the plates with SoC as well as temperature, which is why I always cycle my cell phones at 20%-80% SoC (never exceeding 80% SoC) and have had excellent performance over years. Before you ask if I really keep my cell phones for years - yes, I put re-purpose my old smartphones for data monitoring applications (attached to the inside of my car and hooked up to the CAN bus, stuck near my front door to check the garage door status, things like that, which I set to auto cycle just to see how far these Li-ion cells will go). In any case, I haven't found too much information about how SoC affects the degradation of LiFe(Y)PO4 cells. If anyone can shed some light on this, please share. --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .