Does anyone have any data on the lifespan of LiFePO4 batteries, by which I mean the retained capacity over time? Many manufacturers publish cycle life data showing that 2000 cycles, etc. are achieveable, but I'm specifically interested in the effect of time on the capacity.
For example, if I only cycle my battery once a week, a 2000 cycle lifespan to 85% capacity will in theory last until 2046. I wouldn't mind betting though that capacity is lost year by year.
Does anyone have either manufactuer's data, theoretical predictions or real world experience?