As most Nexus 4 users have found out, while the Google flagship is great at a number of things, battery life is not a strong point. Perhaps it is the Mediaserver process, or maybe overheating, but regardless of the cause, the Nexus 4 tends to run ever so slightly short of battery if you push it too hard on any given day.
While most people would be content just to let the device charge on their desk during the day, XDA user tommmtom decided to do something better. After an unrelated incident broke the glass back cover of his Nexus 4, he decided to go ahead and add a second battery to the device, doubling the capacity.
The process is actually nearly as straightforward as you would think. First, you have to remove the battery cover of the Nexus 4, which iFixIt can help with. After removing the NFC and wireless charging coils, you then must solder leads to the positive and negative terminals of the battery connector, as well as to the four spring contacts for NFC and wireless charging.
At this point, you can put the back cover back on, with the wires sticking out. From here on, all that you have to do is attach the second battery (a standard Galaxy S3 2,100mAh battery can be used) to the back of the battery cover and match the voltages of both batteries. Next, you can connect the leads to the battery, positive to positive and negative to negative in parallel, because you don’t want to double the voltage and fry your device. Finally, you can place the coils for NFC and wireless charging back onto the device and solder the proper wires to them.
After this, creating an extended back cover is totally up to the user, and you can use Sugru, thick plastic, or whatever other materials you have available to cover the exposed battery. However, regardless of how the modification looks, it should roughly double the battery life of the Nexus 4, and the user who came up with the modification has posted screenshots of the Nexus 4 showing 7 hours of screen on time, which is quite impressive.
It may not be pretty, but this sort of very practical user modification is exactly what I love to see from the Android community. I doubt many iPhone users would risk this modification on their devices, but for this user the modification is simply a logical solution to a problem. I don’t know yet if I would mod my own Nexus 4, but the back glass is already broken, so perhaps we shall see.[xda-developers]