[photojay]

My battery is draining hugely WHILE IN AIRPLANE MODE! Not sure how this is possible. 2 nights ago I went to sleep in airplane mode with 59%, woke up with 22%. Last night went to sleep in airplane mode with 29%, woke up and the phone was completely out of juice. The battery usage report shows "Android System" is the hog here, while in the past, before I had this problem, "Screen" was always the biggest hog. Not sure what the heck happened. Trying to figure out which portion of the "Android System" could be doing this. Could it be a portion of runaway script, or something to that effect? Haven't had any software updates (this is the D6633 model). Looked in the system settings and I don't see anything that could cause this while in airplane mode. Any suggestions?

[Rukbat]

Those percentages are percentage of the total amount of drain, not the percentage of battery capacity. (Just so you understand what you're looking at. Android System didn't use 30% of the battery's capacity, it used 30% of the amount of power used. If the phone listed every app that used any power, and carried it to 3 decimal places [some apps pop in, use a tiny bit of power, then close] you'd see that the numbers always add up to 100%. IOW, 100% of the power being used is being used by something - even if only 2% of the battery's capacity is being used.)

As far as what's happening, there are a couple of things.

1) You're letting the battery drain to almost nothing, then giving it a little charge, then letting it drain to almost nothing, etc. Try to never let the battery get below 40% if you want it to last. And once it gets down there, charge it to 100% if you can. See Battery University - How to Prolong Lithium-based Batteries to learn a little. (They make battery analyzers for the industry, so they've destroyed enough batteries to know what they're talking about. It's a whole battery course, if you want to go to the left panel and start at the top.) It's especially important in a phone with a non-removable battery.

2) We need to see the next screen (press the graph on top to get it) to see how long the phone is awake when it's not being used. (It should pretty much be asleep when the screen is off.) Then you're going to have to find out what's waking it. Try Wakelock Detector (if your phone isn't rooted, see Wakelock with non-rooted phone to see how to set it up to work. It's not trivial, but a couple of runs should be enough to tell you which app(s) is/are causing the problem.)

[photojay]

Thanks for the thoughtful reply, Rukbat. Update: I'm aware of the best usage techniques with Lithium Ion batteries, thanks for that. I haven't yet tried the wakelock detector, but I've been putting the phone in Ultra Stamina mode the last few nights instead of airplane mode. In ultra stamina mode I lose 0-1% charge over the 8 hours i'm sleeping. Perfectly as it should be. I'll try airplane mode again tonight and see if there is still a problem there.