[Fascinate Android Development] Syndacate:
A lot of people seem to be confused about this.

From what I understand, the "battery usage statistics" is the breakdown of which components have used what percentage of the battery power that has been drained since unplugged. This means that you can be at 95% power, but still have 75% of battery usage by the display.

Comparative to the display, the CPU uses a very small amount of power. When woken resumed from sleep states and idle processes, the process which the processor is servicing is noted, this goes into the battery usage statistics. If it's a kernel operation or framework thread, it goes under the "Android OS" portion, or if it's an individual JVM instance, the app it's running gets marked in.

This means, if you've used your phone for any substantial amount of time, the display will be EXTREMELY higher than the Android OS simply because the display uses a lot more power than the threads are using pulling the CPU out of sleep state. The only reason the Android OS is higher than most other apps, is because it has A LOT to do (I/O management, pretty sure it does screen buffering too since I don't think there's a dedicated GPU, task management, thread management, process control, so on and so forth). If you want to test this theory, play a 3D intensive game.

The Android OS will most likely be higher than the game because it has to manage all the resources that intensive game wants, BUT, that game will likely be right below Android OS on the battery usage list. Likewise, if you never use many apps like me, you'll find whatever is under Android OS pretty arbitrary, sometimes an app you use, sometimes the phone (the modem will burn through battery pretty quick, too).

As for software versus the screen, if you want to test this, do this:

- Put your phone in airplane mode

- Charge it to full

- Let it discharge, don't use it at all for say 6 hours

- Open and check your battery stats

The Android OS will be higher than the display for once, simply because the OS is doing background management, even if it's just handling timer interrupts for the clock and such, it won't stay in a sleep state. The display on the other hand has been off for awhile.

When I had the extended battery in mine and I was driving across country, like 15 hours of not using the phone at all and only opening it to enter gas mileage and check e-mail on the road put my Android OS 'task' higher than the display of the phone.

Hope that explains it a little better.

From what I gathered, it has nothing to do with how much of your battery is consumed by different components, overall.

In case you're asking "what the **** does this crap have to do with my question" - I'm simply getting at the point where you said you turned your screen down but the display is still higher in battery usage than the other stuff. Hope that helps.

Largest drawers of power under typical circumstances:

1) Display

2) Modem/radio

3) Android OS (kernel + framework)

Where 'cell standby' and 'radio' fits into the usage determines on how quiet the modem is along with how long it has been in stand by. Though everything is reset when you charge. Hope that helps.