[Vibrant General] steel_3d:
I've been seeing a lot of posts on crap battery life around here, and I was chasing my tail about some of them as well, following a lot of misinformation even by senior members. I think I have a good handle on it now, and picked up most of these tips from these forums, so I'm not taking credit for these ideas, just collecting them in one place. Some of my suggestions assume you have root and Rom Manager (see the Tips and Tricks sticky thread on how to get them).

1. If your battery drains in less than a day on standby, you probably have a bad flash of the JI6 modem (either from the OTA update or from a ROM). Flash the JI2 modem from here "www dot teamwhiskey dot com/home/downloads". If the flash fixes it, you may try going back to JI6 if you want, and it may stay fixed. I went back to JI2 and didn't bother going back to JI6, but it has worked for others. With JI2 and 3G on I get just over 24 hours in normal usage.

2. The #2 battery drain on standby is 3G. I turned it off (Settings/Wireless/Mobile networks/Network mode/GSM only) and my phone lasted for 40 hours on Edge with light usage (few phone calls, messaging, quite a lot of web surfing, 2 hours of podcasts). Didn't even feel too slow (I get 140kbps on edge). Can anybody suggest a really good widget for turning 3G on/off? I use the 2G-3G OnOff widget by Curvefish. It's not one-click, it's just a shortcut to Mobile Network Settings, but it works. Note that sometimes it takes a while for the data connection to re-establish after you see the 3G or E icon.

2.5. WiFi always on is a huge battery saver! It keeps 3g off. I can easily get 3+ days with light usage on my home wifi. Settings/Wireless and Network/Wifi Settings/Menu/Advanced/Wifi Sleep Policy/Never.

3. Don't need a task killer. I wasted all my time killing tasks trying to chase down my crappy battery usage, but since I fixed my modem and turned off 3G I know that the 3-5% CPU usage at idle does not hurt my battery. Taskiller for me was actually hitting the CPU constantly, lightly but for no reason, so I got pissed and uninstalled it.

4. Install a CPU usage monitor like Usage Timelines. It sits in the notification bar, very easy on the battery, but tells you if you have a rogue app pegging your CPU and draining your battery. These are the only apps you should be worried about killing. Astro File Manager has a task manager that shows CPU usage for each app, so you can kill the rogue one. I shoot for about 5% cpu usage at idle (at 200mhz - at 100mhz it would be a bit higher).

5. The app Autostarts lets you disable any app from starting on boot or other events like connectivity changes. This is not strictly necessary unless you have a lot of crap apps installed on your phone and they like to start themselves and waste CPU time behind your back.

6. If your battery reads less than 100% as soon as you unplug it from the charger fully charged, or your battery meter sits at 100% for a long time after you unplug it, you can recalibrate your battery meter. To recalibrate: 1) charge your battery to full, 2) unplug, 3) reboot into Clockwork Recovery and 4) Wipe battery stats.

7. There is No Such Thing as "battery reconditioning" (for all intents and purposes). The above procedure only RECALIBRATES you battery METER to read on a more linear scale between full and empty. It DOES NOT make your battery last longer, period. Whoever tells you that is a moron. If your battery is dying in 6 hours, doing any amount of calibration will not make it last longer (I've tried).

8. I wouldn't be too worried about undervolting, overclocking, kernel tricks and superawesomefast ROMS. The CPU drain at idle is so minuscule (as long as you don't have rogue apps) that those things make precious little difference. Like I said, the biggest drain is 3G and other radios. Having said that, I run Bionix 1.9 with the JAC kernel. It drained my battery in half a day at idle until I flashed the JI2 modem. With JI2 it suddenly started lasting over 24 hours, and once I turned off 3G, over 40 hours. I like this ROM and see no need to switch, it's very smooth. But you should be able to get similar battery life on a stock Vibrant.

9. I have GPS on, WiFi never sleep, auto-brightness, and a few widgets on like Weather and friend updates. I have no fancy settings, literally just turning off 3G (or wifi on, which is the same) got me 2-3 days. So I wouldn't waste time fooling around with magic settings (other than wifi never sleep), battery saver apps, etc.

10. If your screen is on all the time and you're playing games nonstop, you're draining your battery quicker than any of the things I mentioned above, so you probably don't care. In that case an optimized ROM/kernel is probably your best bet, especially JIT in Froyo. You can probably save on screen brightness as well.

If you guys have any other tips I'd be glad to add them to the list, but I hope this gives you an understanding of where your battery life is going. Basically: bad modem, 3G, or rogue apps.

Also, I hope this will put an end to trolls calling people whiners for complaining about battery life and saying unproductive **** like "you're a whiner" or "the Galaxy S is just a battery hog, live with it". It's not, you don't have to live with it, nobody should have to, here are your solutions.

Good luck.