Asklemmy

except that manufacturers account for that and calibrate such that what you think are 0 and 100% are actually closer to 20 and 80% respectively.

It's actually the other way around. A safe cutoff voltage to prevent battery degradation is about 4.2V, but most modern phones charge until 4.45V, so they can advertise a bigger battery capacity at the cost of long term battery health. Your phone essentially charges itself to more than 100%

Yes, the battery doesn't charge to "dangerous - could explode" levels. But they very much do still charge to levels that are damaging to long term health/capacity of the battery.

Yes, they tune the batteries so that 100% isn't the absolute cap. But even with that accounted for, many batteries will be above values that would be considered good for the long term health of a lithium cell. 80 percent on most phones is still very much at levels that are considered damaging to lithium batteries.

To put it another way, the higher you charge a lithium battery, the more stress you put on it. The more stress you put on it, the fewer charge cycles those components will hold. It's not like there's a "magic number" at 80 percent, it's just that the higher you go the worse it is. Yes, some manufacturers have tweaked charge curves to be more reasonable. But they've also increased limits. Many batteries now charge substantially higher than most people would consider sustainable.

And after such changes, 80% lands pretty close to the general recommendations for improved battery longevity. Every percent will help, but it's not a hard and fast rule.

Calibrations have gotten a little better in some ways, but all you have to do is look at basic recommendations from battery experts and look at your phones battery voltage to see that almost every manufacturer is pushing well past the typical recommendations at 90 or even 85 percent.

Since the iPhone 15 (pro?) you can also limit the charge to 80%, so it will never charge above that.

Pixels have this too. I believe one plus does too but I don't remember. Idk about anyone else.

iphone charge numbers are mostly made up. The phone shows you whatever number it thinks you'll believe and keeps the phones life long and comfortable.

The notification itself is super helpful if you care about battery health. There are apps that try to do it if your phone doesn't have one, but they aren't nearly as well integrated into the system and are therefore more clunky.

The insane/annoying part is just that the setting is not opt-in. Or whether there's a setting to turn it off.

It hasn't been in a long time. Charge controllers still charge to damaging voltages anyway. 100% isn't 100% but you can very easily check the voltage on phones and many still are into damaging territory beyond 80%.

Turn on "Optimized night charging" in battery options. I think every Oneplus has this.

That's why Pixels and some others have a "smart charge" feature that will wait to charge your phone until just before your alarm time so that it will finish right before you take it off the charger.

why am I going backwards to needing to babysit my phone when it's charging, and why would anyone want to charge their phone when they want to be using it vs when they're asleep?

I honestly don't understand why people have such trouble with this. I can throw my phone on a charger when I go to shower and it's at 80 percent when I get out, and that's enough for my day. I could leave it while I get dressed and eat or something and it'd be at 100 if I needed. I don't need my phone 24 hours a day. And there are many points in my day where I'm not using my phone for an hour that I could spare to charge it. I don't need to leave it burning away permanent battery capacity for hours and hours every night.