[wickedsmile]

Charging phone when you are off to bed is really very bad.

Lithium charging protection circuit could fail anytime due to one of the components in the circuit malfunctioning and your lithium battery inside the phone can catch fire.

Many houses have been burned down to ashes from lithium fire. Just YouTube for 'lithium fire' and you'll see how dangerous it can be.

I usually charge the phone in an empty place where lithium fire won't cause much damage.

[Phlarp]

residential lithium fires are unlikely to be coming from phones. (unless people still have those exploding Notes still kicking around)

Far more likely to be lithium batteries being used or abused in a hobbyist capacity. E-cigs and RC are both ripe for it when users have lower quality cells to begin with, routinely discharge them above the rated current and then charge with sometimes questionable chargers. Worse yet when people try to charge them above the max voltage.

[wickedsmile]

What protection mechanism do we've of one of the SMD resistor or IC in the protection circuit fails?

[Phlarp]

I'm pretty comfortable assuming that Apple wouldn't design a lipo charging circuit that could fail in an unsafe way due to a single component failure, but I can't speak specifically to what those might be.

[saagarjha]

That’s why Apple invests in quality control to prevent this from occurring.

[wickedsmile]

No amount of quality control can work against the long tail events, it's simply impossible.

[saagarjha]

Yup. The best they can do is reduce the probability of it happening.