I have a largish 20AH 48V LiFePO4 I bought from PingBattery.com ten years ago for powering a dual motor e-bike project. I ended up also using it to power a mob

I have a largish 20AH 48V LiFePO4 I bought from PingBattery.com ten years ago for powering a dual motor e-bike project. I ended up also using it to power a mobile robot (rover) project, and sometimes used it for emergency power during blackouts. I went with lithium iron phosphate because it was perceived safer and more durable. Over the past ten years when it wasn't bouncing around inside a rover or e-bike it spent months or years on a shelf when I forgot about it. Most recently I've dusted it back off and use it to power a large shop fan. Because of it's long storage and infrequent charging/balancing the subset of cells that actually power the microcontroller in the BMS were alarmingly low compared to the others, but after a few cycles it seems to have recovered and all but one of the low cells has balanced to the others. The battery still seems to perform well overall.