For Lithium-ion rechargeable batteries, that have never been charged, or been charged like 2-3 times at most, some 2-3 years back, and having since-then been in packaged condition, what should I expect their condition to be ?
Reading this wiki entry, I understand the thing about self discharge-rate and durability in terms of recharge cycles, but haven't found much credible information about unused cell's shelf life. Do they degrade over time, if not used ?
PS> Reason for asking is because someone is offering me a small cache for such batteries (to used within RFID readers), for what appears to be a very good bargain.
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Best Answer
Yes, Lithium-ion bateries degrades over time, even if unused. It is due to a chemical/physical reaction that starts right after manufacturing of the cells.
I can't answer on the state of your batteries. Because it highly depends on the storage temperature and also the charging level of the cells during the storage.
I don't remember the optimal number, and if you know it, don't hesitate to modify my answer, but AFAIK it was around 60%. Thus if you want to reduce the aging effect, you should store your cells at 60% charge. I don't remember the optimal value for the temp.