Battery is acting out


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Sep 18, 2018
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So I've owned my Samsung galaxy s8 since August of last year, and I have to say it has been the best experience with a smart phone for me ever.

Around June of this year, I had a problem with the screen where the upper third of it was darker than the rest, and it was quite noticable, so I went to Samsung and they told me that there was a problem with the battery and the screen and they changed it for free as the warranty was still valid.

fast forward until two weeks ago, I started noticing that the battery would drain extreamly fast when it gets Rufus MapQuest UpToDate below 15% (Almost 1% per 20 seconds or so). So I tried to calibrate the battery by draining it 0% and getting to a 100% without turning the phone on (at least that's what I read on the internet) and still had the same problem, so I did a factory reset of the phone. after I had done it, the same problem still existed but that's not it, the battery life in general became worst.
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Feb 12, 2012
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So I tried to calibrate the battery by draining it 0% and getting to a 100% without turning the phone on (at least that's what I read on the internet)
There are a lot of wacky rumors on the internet - that's one of them. To calibrate the battery (which I doubt is your problem), the phone has to be rooted and you need a calibration app. When the terminal voltage of the battery stops going up (while charging), it's at 100%. Then you tell the app to calibrate and it sets the current voltage as 100% in the system file that keeps that information.

What your problem sounds like, especially since you're complaining that the battery won't hold up lower than 15%, which means that you've probably been draining it quite a bit past that, is that you killed the battery. (It doesn't say so in any instruction manual that I've ever seen, but the best range - the one that gives you the longest battery life - is charge to 80%, charge again when the battery drops to 40%. If you can't charge it when it gets down to 39%, turn the phone off. The battery doesn't care how badly you want 8 hours of SoT, lithium batteries are not deep-discharge batteries. (The only reasons they're used in cellphones is that a) lithium is the lightest metal at normal temperatures [hydrogen is lighter, but you'd need a freezer at least the size of a car to keep a little of it in the metallic state] and b) a lithium battery can be made almost like a bag partially filled with water - you can shape it around almost anything, so it can be very thin. And everyone wants light, thin phones.) If we wanted phones with batteries that we could discharge to death with no ill-effects, we'd need gel cells - they use lead as the electrodes, and lead is heavy.

So contact Samsung for a battery replacement price - they used to (not that long ago) charge $60 (plus, if I recall, your shipping to them). Then keep the battery between 40% and 80% and when an S8 is such an old phone that no one wants one, the battery will still be pretty good.

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