[T-Mobile myTouch 4G Slide] cj chitwood:
@Archangel22

If you have the STOCK battery, and your brightness is at 100%, and you meant each unlock of the three you did took five minutes, then yes a ten percent drain over three hours is perfectly expectable.

If you have a 3.5Amp mugen/anker/whatever battery, something's wrong.

YMWV.

That said, I agree with the guy above, task killers are bad, and the people who wrote Android have explained why (google it). They're also no longer necessary with newer versions of Android because the battery stats are built into the ROMs now and you can see where your battery is going.

From the home screen, hit Menu > System Settings and scroll down to the Device section, in which you will find Battery. I'd hit that. It will show you a graph depicting how long you've been on battery (charging times are of course not included, so if it says ten hours on battery, and you charged for an hour, the graph will say ten hours on battery but show eleven hours worth of [dis]charge history).

There are two important things to note here.

(1) the graph is touchable (I'd touch it), which will expand it vertically to show a finer detail (more exaggerated, a good thing) of when the faster discharges occur. Look below the expanded graph, and you'll see several lines depicting things like mobile network signal, wi-fi, "awake" (phone not sleeping whether you're using it actively or not), Screen on, GPS, and Charging (not necessarily in that order).

Mobile Network Signal is color coded, green yellow red and black. Best to worst. Worst, you'll use more battery because it's trying to find any signal it can get, and using as much battery as it can to get a tower somewhere to talk to it. Where best, it uses less power, because towers are closer with better signal so less energy needs to be pushed into the antenna to maintain communications.

Wifi is just one color, but you either have it or you don't. With wifi, the phone tries to maintain a connection even while sleeping, which can use more battery than the mobile phone radio, or not, depending on a number of variables. I have seen it go both ways.

Screen on -- this is your biggest killer of battery. Backlights take power. Dim your screen when you don't need full brightness. Indoors, mine rarely goes above 50%.

GPS -- not a big battery muncher since the GPS is a receive-only chip, but it is an unnecessary drain if you're not using maps or geotags in photos or some such. If you don't need 10-foot-radius accuracy, turn off your GPS and let the network judge your general location.

The second important thing here (hit the back button out of the expanded graph) is that the items below the small graph are also touchable. Do so and they'll give you some details about the items you see. You'll probably see screen as the #1 item, probably accounting for more than 50% of the overall drain if you use the phone at all. Touch these, and it'll tell you how much total time the screen has been on, or how long the phone has been used for calling, "cell standby" says how long the phone has been active but not in use for calling (waiting for an inbound or outbound call, e.g. in standby) and will also say how long the phone had no signal (implication being if no signal, then radio keeps looking for towers to talk to).

Take the above into consideration. If you use a particular app *A* *LOT* it will be higher in the list. Games and the like are big consumers, as are any apps that keep the screen turned on or make a lot of use of the sensors in the phone (an example being wardriving apps that keep the screen on, a gps-centric map displayed, with compass-based map orientation, while listening for wifi signals and saving all data to the SD card in realtime).

Occasionally there will be an errant app that gobbles it all up. For that, you can configure the long-press of the "back" button to kill the foreground app (so switch to the errant app first, of course) or you can go into settings, app management, stop the app that way.

Or get a task killer, the quick easy way, just it's not recommended to leave them on "automatic" mode.

Hope this helps.