[Galaxy S II General] Gustopher:
Battery Life

Isn't it interesting that some folks are experiencing great battery life while others are complaining about how terrible it is.

While there may be subtle differences between builds and the radio being used, my experience has been that performance is nearly always related to system and/or widget settings.

I have previously been fooled into thinking that all of my other variables remain static between flashes, but given that a reflash of gapps is sometimes required, there is real scope for things to change in ways that aren't always obvious.

Is there a definitive ju-ju, way of reading the chicken entrails or method of casting the runes that will guarantee good battery life? No.

Is there a scientific approach that might help identify the source of the issue? Yes. It's called trying stuff.

Some combination of the following 'stuff'

may

help but is infinitely better than sitting watching the battery counter tick down. Be warned that a solution may take several days:

Install BetterBatteryStats - I have found it difficult to make sense of, personally, but it may help identify where the bodies are buried

Turn off wifi and re-enable it again after every flash - someone on here recommended it and while I can't see how it makes a difference, it seemed to be a part of my going from poor to very respectable battery recently

Pull the battery, wait a minute and reboot - similar corollary to the above. Worth trying

Check your sync settings - I keep wifi on all the time and use push email. It doesn't seem to be much of a drain in my case. However, I discovered that a couple of Google sync settings that I thought had been disabled had been re-enabled somehow

The two biggest pains in my experience have been Browser sync (turn it on and off as needed if it is important to you) and Google+ sync

Don't go anywhere near Latitude or anything similar - seems to be poison for batteries

Widgets! Check they haven't got their knickers in a twist. Remove for a while and monitor battery drain. Be prepared to be ruthless. If battery improves, add the widgets back one at a time and see which one starts the drain

Be prepared to stop all syncing too - staying connected is the reason I started buying smartphones a decade ago, so I wouldn't keep it off, but at least I'd know the cause of the drain and be prepared to carry an extra battery or a charger

Even if it is the syncing itself that turns out to be the problem, it may only be one aspect that's the problem - try moving from push to a 30 or 60 minute sync for example, or turn off Contacts sync temporarily, or Calendar, or...

It can sometimes be worth removing and recreating the account

Freeze or remove some of the bloat that's not required

This isn't supposed to be a definitive list - there will be plenty of other stuff worth doing. The message is be patient and be scientific - it may take a while but intrinsically CM9 is fine on battery, I'm certain of that, it's all about how it's used.

It's a bit like people saying that they are obese because they are 'big boned' or of a 'muscular build'. Keep shovelling the chips in without taking exercise and the laws of nature recognise only one outcome...