My theory on batter life...

[aer127]

So, yesterday my Lumia was sitting at 48% charge. I opened a few apps, used them, then put the phone in standby. Several minutes later a pressed the power button on my phone again and it would not come out of standby for whatever reason. So, I did a soft reset (holding power and volume down buttons). After the phone rebooted, I checked the battery life, and it now read 73%. I'm starting to think this whole battery life issue could just be an issue with the OS and the algorithm used to determine remaining battery life. Has anyone else experienced similar behavior?

 

[andrewkeith5]

I haven't experienced similar behaviour, but I have noticed that the "estimated time remaining" indicator is wildly variable throughout the day, and that the battery appears to degrade faster through certain %ages than others...for example, the first 10% degrades very slowly, but from ~65% to ~50% it'll drop rapidly, then slow down again, then the last 15-20% basically vapourises even with battery saver...on my 7 Pro, Battery saver took the time remaining at 20% from ~2-3 hours to ~5-6 hours, on my L920 it takes it from 1 hour to 1 hour...

 

[Steve Ridges]

The estimated time remaining is based on CPU load over the last x min (I think around 3 min but I'm not sure). If I'm doing something processor intensive, the estimated time left will only be a few hours and I can feel the phone heat up. If I close my back ground tasks and wait a couple min and check again, I'll have 2 day left.

 

[LazyLemming]

It is a difficult thing to confirm, but yes, many users have reported that the battery indicator would do weird things. Some had hours of battery left at 0%, others would take 2 hours to charge 2%, etc. This is one of the reasons folks have recommended calibrating the battery by a full drain followed by a full charge.