A friend of mine recently called me up with a battery problem. He had done some troubleshooting on his own, and already come to the right conclusion, but he wanted a second opinion.
His Galaxy S5 Active had a strange issue: if he unplugged his phone, it would reboot or die even though he had over 70% battery left. However, of he put his phone in power saving mode, it would work like it was supposed to. If the phone was plugged in, he could use it all day. So he figured that he needed a new battery, and he was right.
Lithium ion batteries have to meet a special safety standard, and from what I understand, that means that they have a special charging and discharging protection circuit. Here is a little except about it from http://batteryuniversity.com, where you can read all about it:
“Further layers of safeguards are solid-state switches that measure the current and voltage and disconnect the circuit if the values are too high. The protection circuits of Li-ion work on this on/off basis. (See BU-304b: Making Lithium-ion Safe.) All switching devices have a residual resistance that causes a slight increase in overall battery resistance and a subsequent voltage drop.”
In any event, of you have a cell phone battery that performs as normal, but once reaching a certain percentage above 0 it does suddenly or randomly reboots, then most likely this circuitry in the battery has failed. It is easy to think there may be another problem, say with the phone, because the battery still holds a charge. As for my friend, a new battery had him up and running in no time flat.
I recently purchased a new battery for my note edge, not because of this issue, but because the battery did not hold a charge for as long as I thought it should. Turns out I was correct. They say a cell phone battery is only good for 3 years, and that includes the time on the shelf before you started using it. It will last a long time, but performance will diminish over time.
Here what I bought (and no, this is not some sort of kickback add):
Samsung 3000mah Battery for Samsung Galaxy Note Edge – Non-Retail Packaging – https://www.amazon.com/dp/B00RYS9UIY/ref=cm_sw_r_other_apap_Yhn2fEg4qCmPC
It was only $12, and took about 3 minutes to replace because I stopped to take a picture (which takes a while when your usual camera is the phone you are working on). If you have had a phone for more than three years, I highly recommend a new battery. The difference was immediately noticeable!
Linux – keep it simple.