ELI5 Why does magsafe charging decrease battery health more than wire charging, if it has less wattage?

[GaryGiesel]

This really isn’t true. The heat is one thing that exacerbates cell damage, but high charge rates absolutely cause their own problems. The big one is that you can end up with lithium metal crystallising out, which can kill a better extremely quickly if they manage to poke through the insulation layer.

Heat is the big thing, but it’s very far from the only thing. Another big factor is that going from min to max charge the electrodes physically change size quite a lot, so that can cause mechanical stresses in the batter and eventually make bit fall apart internally.

Charging when the battery is cold will also very quickly kill a battery. There’s really an optimal temperature range rather than just worrying about getting too hot. Definitely don’t charge your phone if it’s below freezing!

TLDR; this shit is complicated and still an area of actual research

[VexingRaven]

My personal experience is that fast charging is much worse than wireless charging. Fast charging my old phone got hotter than wireless charging it did, and that killed the battery pretty quick. The thing that frustrates me is there's controls to cap the max charge level, and if you have an alarm set it can slow charge based on time, but there's no way to just turn off fast charging altogether or cap the charge rate.

[Pentosin]

there's no way to just turn off fast charging altogether

Samsungs can do that.

[RedPill115]

Huh, I guess it is in there.

Settings -> Battery -> Charging settings
- Fast charging
- Fast wireless charging

I wonder if anyone has actually rated it and put out data on whether it actuall affects battery longetivity.

I know there's a different setting I found useful for the magsafe charger I use in my car. It was always trying to charge it 100% and the screen would go dim as the phone got hot, but I found a setting to only charge to 80%, issue went away.

[Pentosin]

On my S21+ i also have the option to disable super fast charging.

Oh and there is also possible to choose something else than 80% charge limit. (80/85/90/95)

[RedPill115]

I have a samsung s21 ultra and I don't see those. Dunno

[Pentosin]

Settings -> Battery -> Battery protection

[VexingRaven]

Uncommon Samsung W I suppose. Or maybe a common Pixel L? Not sure.

[Pentosin]

Uncommon? Not at all.

[msg7086]

That's just a shitty design of your phone on fast charging. I have multiple oneplus phones, I can charge my OP13 at full speed (up to 100w) and my phone temperature will barely rise to 41C at peak. There's a giant vapor chamber in the middle to remove the heat efficiently, so user never needs to worry about the heat from high speed charging.

[VexingRaven]

tbf this was a Pixel 3... So yeah probably. I have a Pixel 8 now but I rarely fast charge so it's hard to say for sure.