[EVO 4G Android Development] Biofall:
I don't know what you are coming from (ROM and kernel wise) but 2.2 generally shows sub par battery life, and the big improvement here is sleep time. Make sure to do all of this:

My tips for good battery life:

1.	Turn off all radios when not in use (gps, Bluetooth, wifi, data, 4g) using a widget like the default HTC power widget or switchpro from the market.

2.	Use SetCPU in compliance with whatever your custom kernel allows. This site will explain the basics of SetCPU: http://www.pokedev.com/setcpu/

Profiles from SetCPU should usually involve these for battery life optimization:

a.	Screen off at the minimum clock speed for both, with the max raised on level if sluggishness is apparent

b.	A temperature greater than “X”

c.	General power related profiles that lower cpu speed at lower battery levels

d.	Here are my SetCPU profiles: http://yfrog.com/jtsnap20100823205138p , http://yfrog.com/5lsnap20100823205142p , http://yfrog.com/mzsnap20100823205145p

3.	Juice Defender is my new fav, explanations on their page, search it on the market for free, or upgrade for more features.

4.	I love live wallpapers, and I’ve always been a fan of pixel zombies, but they are really only good for showing off due to their battery drain.

5.	Go to menu<settings<wireless & networks<mobile networks<disable always on mobile data

6.	Set your screen timeout to something that fits you so that your phone doesn’t stay on when you don’t manually turn off the screen. Also with this, manually turn off your screen when you’re done with your phone.

7.	Everyone has that issue where the first ten percent go the fastest. This is due to two things. One is that these types of batteries stop charging once they get to 100% to prevent damage, and begin charging again at 90%. This means that you could potentially unplug your seemingly fully charged phone at 90% actual charge. The second is number 8.

8.	Use the trick described in this thread, it works: http://xdaforums.com/showthread.php?t=701567

My idea behind how often you should do it is once a month, if you flash a new ROM, or if you stop noticing the benefits.

9.	Task killers used to be the shiz, but in light of recent testing, really don’t do anything but force apps that the android OS needed to be open, and thus didn’t close, to re-open. So try not using them, unless for stuff like trying to figure out why your phone isn’t sleeping with system panel. You really won’t notice a performance difference, and the adverse effects you aren’t seeing will stop :P

----When it comes to people claiming 20 plus hours of moderate/heavy use out of their current setup or other ridiculous absurdities, consider my position: No matter what you do, the Evo battery is the Evo battery. You can tweak it and customize it with kernals, ROMs, and settings, but none of that will turn your battery into a car battery. The main problem (besides a false sense of pride) that leads to these reports is the misunderstanding of what the usage levels are, so here’s my best summary:

•	*Light usage – Phone screen actually on for maybe 4 hours. Things like a few texts, some emails, 20 minutes web browsing, etc.

•	*Moderate usage – You watched a few youtube videos or similar apps, sustained web browsing, hundreds of texts, some games. Hours range from about 5-10 of screen on

•	*Heavy usage – LOTS of video watching and games, or some high def gaming/movie watching for at least an hour to an hour and a half in total, with lots of emails and texts, browsing, and other app shenanigans

*I’m sure everyone doesn’t agree with all these numbers, but this is most likely a good average of what powerusers think. All specific hourage may vary due to differences in phones, batteries, ROMs, and kernals… Which also means that most battery comparisons are pointless; it’s only what you can improve on that counts!

I’ll update this whenever I see good stuff, people remind me, or I remember/come across things I do.

Hope it helps everybody!