If the battery lasts considerably less than it did before, you'd better pull it out of the electronic device and go to replace it with a new one. The LG-produced Nexus 4 smart phone has an internal battery and it seems to be non-removable. but, it is possible to swap out a new battery (2,100mAh, 3.8V, 8.0 Whr) without tearing apart the device completely.
How to Replace/remove LG Nexus 4 Battery properly
* Press and hold the power button of your device to shut it down.
* After the processing is fully completed, use a screw driver tool like T-5 Torx to disassemble two torx screws on the back size. Then open some plastic clips.
It is very easy to do by yourself and a good time to ensure that you have a back up battery in case you need it.