How can I fix my battery after it has been rooted?

[Ali Koenig]

I have a Galaxy Note ll I was having battery issues where once it reached about 30% it would die in twenty minutes. I mentioned this to someone and he rooted my phone for me and did some things to "fix it", but now my phone is completely messed up. After he fixed it he told me to charge it to 100%, use this battery calibration app, let it completely run out of battery, then charge it to 100% after it died while it was still off. I did this, restarted my phone and used it like normal, then a few hours later my phone started freezing up, the battery jumped from 50% all the way to 17% percent and kept locking up. I have no idea what to do.

 

[Rukbat]

Sounds to me like a bad battery. The good news is that a good replacement is $16, or you can get 2 and a charger (that can charge the one in the phone and the one not in the phone at the same time) for $25. Look at Amazon.com: note 2 battery for the Anker (3rd and 5th) items.

Keep the extra battery with you (in a plastic bag, so you don't weld your keys together) and when the one in the phone gets down to about 40%, swap them. You'll be surprised at how long they'll last if you don't discharge them past 40%. (I still use the original batteries in my spare phone - from 2004.)

As far as calibration, that's one of the big misunderstandings about Android. The file being changed when you "calibrate" the phone just keeps track of what percentage of battery use is being used by which app. It has nothing to do with how fast the battery is used or when the phone shuts off.

However ... with any new battery, fully charge it before even turning the phone on. then use the phone until the phone tells you to recharge it (which may be with 5% charge left - this is the ONLY time you discharge past 40%). Fully charge the phone (preferably turned off), then use it again until the phone tells you to charge it. Go through 3 cycles of full charge, full discharge. It won't hurt the battery (it'll shorten the life by a few days at most - out of a few years), but if the battery has been sitting on a shelf for a few months, it'll condition the battery so it'll last years longer.

BTW, rooting the phone has about as much to do with the battery as it has to do with how fast weeds grow in your garden. All rooting does is install a file (or two, depending on what you use to root it) and one app. If you don't use them, they don't have any effect on the battery. If you do, they each run for a fraction of a second and use less battery than having the screen flash on just long enough to see it. Well, I guess rooting does have more to do with the battery than with weeds, but not very much more.

 

[Ali Koenig]

I will probably most definitely buy a new battery(ies) then, what I do not understand though, is why it is so much worse now, after having been rooted.
The only issue I had before, was that it lost charge ridiculously quickly after it reached 30%. Now it goes from 100% and quickly goes down, freezes at about "half" battery, then shuts itself off, turns itself on, and is then in the teens of percentages. I have taken the battery out a few times when it shuts itself off, and then turned it back on myself with the same result. Once it went down to 3%, stayed there for about half an hour, suddenly turned off and on, to then be at 17%.
I just let it die again, and now I am letting it charge while off to see if that makes a difference.
I am terribly un-tech savvy, but even with my minimal knowledge in anything electronics, I don't think it would have been able to change overnight without something else going on.

 

[Rukbat]

I will probably most definitely buy a new battery(ies) then, what I do not understand though, is why it is so much worse now, after having been rooted.

It's due to the fact that what's happening gets worse over time. You're just noticing it more since the phone was rooted. (It's like buying a new car of a make you never had before - suddenly you notice how many of that make you see on the road. They were always there, you just weren't taking particular notice.)

The only issue I had before, was that it lost charge ridiculously quickly after it reached 30%. Now it goes from 100% and quickly goes down, freezes at about "half" battery, then shuts itself off, turns itself on, and is then in the teens of percentages.

These are all indications of the same thing. It's a bit technical, but lithium batteries grow little crystals when they're being used. (The industry is working on ways to make batteries that don't do this, but it's going to be at least a few years before they even figure out what to try.) Sometimes the crystal will short the battery. That's enough to shut the phone off. It's also enough to fracture the crystal so it's not there any more. When you turn the phone back on, the charge will be anywhere from the same (for a tiny crystal) to almost dead (for a very large crystal). The more it happens, in some batteries, the larger the crystals get.

I have taken the battery out a few times when it shuts itself off, and then turned it back on myself with the same result. Once it went down to 3%, stayed there for about half an hour, suddenly turned off and on, to then be at 17%.

It was partially shorted at 3%. Eventually the short burned out, but the battery was down to 17%. (The percentage you see is an estimate - it measures the voltage of the battery, which is a VERY inaccurate way of measuring the state of charge. But anything more accurate would cost about as much as a few expensive cellphones.)
I just let it die again, and now I am letting it charge while off to see if that makes a difference.

I am terribly un-tech savvy, but even with my minimal knowledge in anything electronics, I don't think it would have been able to change overnight without something else going on.

Lithium batteries discharge by themselves even if they're not in the phone. It's about 5% in the first 24 hours, then about 1%-2% a month. So yes, it can change a bit overnight, especially if it's totally fully charged (which it isn't if you unplug the charger the minute the phone says the battery is charged). The closer to 100% charge, the faster the self-discharge in the first day.

Almost everyone is un-savvy when it comes to batteries, I just happen to have been an engineer in the field for a few years. I see most people wanting to get the most time they can out of each charge, meaning using it until the battery is down to 1 or 2 percent. That's like sprinkling a little lead in your food. It doesn't kill the battery right away, but instead of at least a few years of almost full performance, it means that the battery will be dead in 6 months or so.