Re: Fully charged, protected 18650,storage duratio
In my experience, li ion batteries self discharge after a month or two. I have a Canon S100 digicam and carry it with a spare battery in my beltpack. If I freshly charge both batteries and then don't use either one for a while, both go flat. They are good for a few shots but then need to be recharged. It's the same way with my Sony camcorder which I have several batteries for (NP-F550 and NP-F960). It seems to me that the very large NP-F960 pack (which I think has six 18650's inside) is at 50% after 3 months or so. And it's been the same way with any number of cellular phone batteries. After a few months, they power up the phone just fine and show full strength on the battery meter, but go flat fairly fast and need a recharge.
It's possible that some other li ion cells have slower self-discharge, but obviously not all do. So, I'd take the Battery University claims and any manufacturer claims with a grain of salt.
If you're looking to stash a flashlight away and have full strength batteries a year later, use lithium primary cells, not rechargeables.