Android-based devices are often quite different in how they handle a critically low battery compared to non-smartphone devices. When the battery is somewhere in the vicinity of 1%, the device turns off itself. Naturally, this does not mean that the battery is totally empty, and accurately judging battery reserve capacity requires calibration. Well calibrated batteries can often give you an extra hour of device working time.

To properly calibrate your battery, you need to completely discharge it and charge to 100%. This is especially important when your battery is recently replaced. Naturally, though, these deep cycles are deleterious to your battery's longevity in the long run, so you want to do this sparingly.

XDA Senior Member zst123, author of other Xposed modules such as Soft Keys Fade Mod and Per App Fonts, made a simple module to disable the auto shutdown of the device when Android detects a critical battery level. When the device attempts to shut down, a special notification pop ups with information regarding this attempt. Naturally since this is an Xposed module, your phone must be rooted and have the previously covered Xposed Framework by XDA Recognized Developer rovo89 installed.

If you suffer from abnormally poor battery life and you feel like an improper calibration may be the culprit, head over to the module thread and give this a try. Just note that you will inevitably lose whatever data you're working on when the device shuts off, and you may even damage your OS if the device is modifying a /system file or if you suffer from NAND corruption. Furthermore, keep in mind that repeated deep cycling of lithium ion/polymer batteries will dramatically increase their wear, so only use this sparingly.