If the voltage of a lithium-ion cell drops below a certain level, it's ruined. Lithium-ion batteries age. [Source]
As an owner of quite a lot of expensive mobile devices (lots of Apple stuff for example) I wonder... what if I, say, put my Airpods in a drawer at, say, 3% charge and "forget about them" for a few months?
Li-ion: 5% in 24h, then 1–2% per month (plus 3% for safety circuit) [Source]
Will my device be unusable? As I understand it I won't be able to charge it anymore?
Also: How does Apple (or any other manufacturer) make sure that devices in warehouses etc. don't "die out" during the time they're in there? I know that Apple devices usually come out of the box at least partially charged, but I assume Apple doesn't charge the devices to 100% anyway. But what if the charge drops below "0%" (or: the 'certain level' from above quote)?
Also: what is "ruined"? The above quote implies the cell being unusable, beyond repair, FUBAR. However:
The protection circuit turns off and most chargers will not charge the battery in that state. A “boost” program applying a gentle charge current to wake up the protection circuit often restores the battery to full capacity. [Source]
and
Some battery chargers and analyzers (including Cadex), feature a wake-up feature or “boost” to reactivate and recharge batteries that have fallen asleep [Source]
Would such a 'wake-up' be available in consumer products (laptops, phones, earbuds, whatever) or would this be put only in industrial stuff?
Lithium-ion batteries age. They only last two to three years, even if they are sitting on a shelf unused. So do not "avoid using" the battery with the thought that the battery pack will last five years. It won't. [Source]
Is that information outdated? I have had quite a few mobile devices over the past decade(s) that lasted much longer than that.
I'm trying to make sense of a lot of sources that all seem to contradict each other one way or another.
Software reported "battery percentage" != state of charge
Hence the quotes on "0%" and 'certain level' reference). I'm aware the reported percentage and actual charge differ; I'm talking about actual percentage/charge, not reported. Thanks for pointing this out though! \$\endgroup\$requires a solid background in solid-state chemistry and electronics
I agree, but unfortunately this isn't something you can expect from an average consumer. But if it's that hard to come up with a "common rule of thumb" then maybe there should be some symbols/logo's/whatevers on the devices that tell a consumer how (not) to treat the battery. I have no clue if the batteries in my airpods should be treated equally as the batteries in my Apple Watch, iPad or Macbook for example. Especially since some devices are from ~2012 and others from ... yesterday 😛 \$\endgroup\$