Originally Posted by McGilljam
It's prolly one cell in the battery that are "broken".
Had that on my X1. There are 3 cells in the battery and if one of them doesn't work as it should, the battery only delivers 3-3.1 volt.
Your phone "wakes up" at 3.335 volt but dies at 3.1. I've been measure it myself.
My phone are now back in business with a new battery, a new batterycover and latest software. No problem if you have guarantee...
PS... Try to avoid one thing. Avoid heat in battery. Lithium hates heat.
You are right, man.
Usually, if you discharge a battery till the very last drop, it can happen that:
A) one of the cell goes beyond its safety level, and it "breaks". That's unrecoverable, AFAIK.
B) the cells gets unbalanced, and you nedd several charge/discharge cycles to get them balanced and fully recovered.
Add to this that Usb charging is usually unable to wake up an almost totally drained battery. This won't happen with a normal charger, but Usb charging voltage is lower than normal (of course, it's usb not home plug!) so it has not enough power to wake up the dead battery. If you leave your device in charge for some minutes, it will eventually manage to wake the battery.
However, I noticed that the X1 has a bad power management. Usually my X1 low level battery threshold varies between 10% and 5%. One week ago, at 10% it just shut down and won't recharge, showing me the red light over power button. Removed battery 3/4 times and charged with home charger, it gets recovered. Try to plug the charger, remove the battery and insert it again, doing all this with the charger always plugged.
In my opinion, that's really annoying, I never know when it *really* has a low battery!
Device: Xperia M
Bootloader: Unlocked CWM
Rom: Stock ROM, customized