So I managed to watch youtube for over an hour. On my phone. WHILE IT WAS AT 0%.

It was on zero for 2 hours straight. No charger.

How.

Is it an Energizer? 😉

Sounds like you need to recalibrate.

@Root Nah it usualy dies at like 1% but for once Samsungs Maximum Power Saving Mode seemed to do a very good job

Special YouTube algorithm... you can’t listen to music with the screen locked but it’ll extend your viewing time!

Witchcraft! Burn and salt it.

You probably overdischarged your battery. Enjoy your reduced capacity in the future.
I'm almost surprised your phone didn't burst into flames when you plugged the charger back, since lithium batteries like to throw a fit when you start charging them after an overdischarge.
Make sure your phone does not overheat to much

@endor Didnt overheat at all... I hope that it was a visual thing (as the 7% before that went pretty quickly).

@endor Seems good I guess?
Check says good and it can reach 100 without recalibrating.

Afaik all the battery calibration apps for Li-ion are bullcrap. The battery stats are cleared when you charge it fully.

Maybe there's a bug that prevents automatic shutdown at 0%, or maybe the estimation was inaccurate for some reason? The battery probably has hardware protection for over discharge, which you don't want to trip.

@WIPocket that 100% is based on voltage, not on total capacity.
You can still reach the maximum voltage, but the total battery capacity (mAh) will be less.
Lithium batteries degrade over time and charging cycles, but overdischarging speeds up the process. Kinda like jumping down a bunch of stairs at once rather than walking down step by step slowly.

The exact extent of the damage is hard to predict, since it depends on many factors, but if you start noticing your battery lasting a little less than usual, this is why

@endor Well it says "good" and the battery is lasting pretty normally so far. I still think it was an estimation bug (it did go from 7 to 0 in like a minute).

@electrineer I cant think of a bug that prevents a shutdown at 0%, but maby Samsungs MPSM/UPSM had something to do with that...

@WIPocket maybe you got lucky - you might want to avoid that in the future though.
The quick discharge at the end is normal, the discharge curve of a lithium battery is not linear

@endor Ik its not linear, but 7 in a minute is just too much... My phone isnt THAT old

@WIPocket to give you a better idea. The exact voltages may differ, but li-ion batteries typically operate in the 4.3-3.0V range. The last few % are drained very quickly (this is normal behaviour).
As the battery gets older, the whole curve gets compressed to the left

@endor Oh, makes sense now.
Tho Im pretty sure the percentage display accounts for this (better for the user) and that may be the source of error...

@jAsEtRiX aNoThEr jAsE!?