Battery drain in sleep, especially when under 50%

Well, that wakelock is a bit higher than ideal...but its not a stuck wakelock. At just over 10%, it appears to be a legitimate wakelock, though perhaps a bit excessive. This is likely contributing to poor battery life, but its likely lesser than the main culprit ( assuming its not just a series of smaller issues compounding into a bigger one. Much less likely, but possible. )

Screen on time would help ( just click Screen and it will tell you. Though, guessing you don't have that for the above posted screens, so would need a full set of fresh screens as well. ) Also, you can select the graph at the top for a more detailed graph, including a number of other bars that might show a pattern. A screenshot of this would help as well. The Cell Standby also includes a "Time without signal" that would be of use.

Finally, I would try getting the app called "Phone info". Normally we can get to this by dialing a special number, but for whatever reason it's not available on the VZW S3 Inside Phone info, select Battery information. You'll get lots of interesting information about the battery such as the reported health, current voltage, and temperature.

If you can nab screens of the above at like 100, 50, 25, and 5 percent that could help.

Currently, as you may have guessed, one of my leanings is simply bad battery. Nothing stands out as terribly wrong with yours, it just isn't getting the life that would be expected as shown by your usage. ( IE: The phone doesn't appear to be on a whole lot as screen is a lot lower than normal, but there also isn't a massive wakelock. So you should be looking more in the 1-2 days rather than 12 hours range. )

My second leaning is a radio problem due to the Cell Standby being at the top. Normally for anything above fairly light usage, the Screen should be on top. However, if you have moderate usage ( Battery expectancy of around 24 hours ), but there's something wrong with the radio causing it to pull a lot more power...it could pass up Screen, and halve your battery life.

Either one of those could go with the part of the battery draining faster later in the day. Either your daily habit tends towards worse cell connection during the later half of the day, or the problem with the battery causing a faster drop than would be expected.

Another recommendation is to actually let the battery die this next time. Go until the phone shuts off, then plug it in and charge to full with the phone off. One problem with the battery could actually be a false report of how much is left. With lithium-ion there is not a way to tell the actual amount left with much accuracy...so the operating system guesses. This guess is based off of previous lifetime of the battery. Letting it completely drain, then charge to absolutely full, helps to calibrate this and let the OS know just where the bottom and top actually are. ( This "Calibration" only needs to be done once btw. Don't keep repeating it. )

Li ion bateries run from 3.6-4.2 volts during the useful output. Fully charged is 4.2 volts and down at 5% it will be around 3.6. The batt % is just a readout of the voltage.

Minimike said:

Li ion bateries run from 3.6-4.2 volts during the useful output. Fully charged is 4.2 volts and down at 5% it will be around 3.6. The batt % is just a readout of the voltage.

Click to expand...

Indeed, however: voltage is spiky, non-linear, and low resolution. Because of this, it must be largely ignored by the OS. Voltage is indeed where it gets its base readings of full and empty for calibration however. From there, each company tends to create their own algoritm using various factors to try and guess the actual amount currently left.