Comment by yhjc2692
9 hours ago
Afaik mobile electronics’ power circuitry is designed so that power goes straight from charging port to the processor, without constantly charging/discharging the battery, once charging is complete. Unless the system suddenly draws a lot of power (more than the charger is supplying) - which is unlikely in a smartphone.
This is true but lithium-ion batteries degrade even while not being charged or discharged, and this is worse at the extremes of the state of charge (including fully charged), and at higher temperature (and often a plugged in device is on constantly and therefore spends more time at a high temperature than it normally would), so it's still not great for the battery. A lot of devices have a mode where the batter is kept at a lower state of charge if it's been plugged in for a while to try to reduce this.
Some phones bypass the battery when plugged in, but not all do. I know it's advertised as a feature of some gaming phones because graphics-intensive gaming is one use case where you'd want to use the phone heavily while plugged in.
Even then, some phones that advertise bypass charging are actually using a software-based implementation, and they can still end up with swollen batteries after being plugged in for extended periods.
Steamdeck lets you set your preferred % and the dock does pass through charging/power, which I love because that combo guarantees the longest possible life for the battery. I turn it back to 100% for flights, otherwise leave it as 80% at all times. Mine is almost 4 years old now but I don’t feel even a hint of battery degredation yet.
AFAIK this is rarity in smartphones and most are charged through battery, which is why those few which have it advertise their direct/bypass charging feature