There seems to be a consensus that unattended charging of lithium ion batteries is “bad”. This advice seems to be repeated for both protected and unprotected batteries.
I am curious though… we all leave our phones and laptops plugged in charging overnight unattended, why are flashlight 18650 li-ion cells different? I understand the risk vectors and the mitigations, protected batteries, avoid under/overcharging etc… is it simply that the protection circuit in an iphone or a macbook is of significantly higher quality than say a Fenix branded protected battery, such that the risk just isn’t there for an iProduct but a flashlight manufacturer’s product doesn’t quite carry the same level of trust?
Is it that a laptop has more than one protection circuit due to its size?
If it isn’t these things, why is the advice for a laptop different for a torch? Even when using an unprotected battery I am fairly confident my Xtar charger isn’t going to overcharge it and my light isn’t going to over-discharge it, are we just dealing with battery manufacturing defects at this point?
It’s no different, as long as you have a quality charger and batteries. But I don’t leave my laptop plugged in when I’m sleeping or not at home. 99.999% chance nothing will happen, same as with a quality charger and 18650 cells. But it’s really simple to unplug a lithium-ion device or skip charging when I’m not home, so why not?
Other than that, I don’t “monitor” the charging or anything like that. But, I’m around to hear the smoke detector if it ever goes off.
Like @WalkintoTheLight, I don’t charge Li-on when I’m not around, which means near by. I don’t ‘hover’.
I DO charge them on a metal shelf, using quality chargers (vetted by BLF) with a smoke alarm and extinguisher very near by.
We do hear of problems here occasionally. Seldom is it dire, mostly a charger that is questionable or misbehaving and needing replacement. When you consider the number of members, and the incredible number of charges going on it’s a pretty tiny risk.
I’ve had charger bays fail to charge. Never had an overcharge issue. Never had an overt failure of any sort in 10+ years of Li-on, and twice that of NiMh.
1/ I try to buy good stuff (being a cheapskate: at the lowest price).
2/ NEVER charge batteries and cell’s unattended. (yes-yes, insurance covers phones and PC’s).
3/ Even when around, I do the charging on a spot with the least chance to set something afire.