[Android Q&A, Help & Troubleshooting] mr72:
If you want to improve battery life without sacrificing performance, I would recommend the following:

1. get SetCPU

2. Main tab, set scaling "ondemand" and leave to min 384000 and max 1512000. Check "set at boot".

3. Profiles tab: Check "Enable", and then create three profiles

a. Charging USB/Full

i. Max 1512000 min 384000

ii. scaling: ondemand

b. Battery < 40%

i. max 124200 (or however low you want to tolerate), min 192000

ii. scaling: powersave

c. Screen Off

i. max 918000 (or go as low as 648000 if you like), min 192000

ii. scaling: powersave

3. Set the screen brightness to minimum using a brightness widget. If you must use a brighter screen, set it brighter only when you need it.

4. Turn off wifi. Turn on wifi only when you are going to actively be using it.

5. Turn off push email. Check your email infrequently, like every 15 minutes or less frequently.

6. Don't use location services with apps besides maps. And don't set a home screen weather widget to update the weather all the time while the phone is screen off in your pocket.

7. Find other things that cause network access, particularly while the phone is idle in your pocket, and disable them.

This will improve your battery life SOME.

The fact is that the max CPU doesn't affect your battery life very much because your phone rarely uses the max CPU rate, and when it does, it is usually briefly. And when you are using max CPU, usually the screen is on. The screen being on will consume more battery than the CPU at max, so if you can make the things you do with the screen on happen faster, then you will save battery. For example, if I am going to reply to a text message, the screen has to be on. If I scale the max CPU to 480000 then it will take me three times as long to type my text so it costs more battery than to run it full on. If your usage pattern is to play games or watch Netflix movies all the time, then long battery life is not compatible with that usage pattern.

The thing that consumes most battery is screen on time. Usually when the screen is on you are also doing something else with the phone like navigation or watching videos, surfing the web, etc., and those things also use heavy CPU and network access, which is like a triple whammy on battery life. So do what you can to reduce screen on time.

I don't think slowing down the max CPU is going to have a significant effect on battery life. The settings I suggest for SetCPU work great to keep the CPU running slower when the phone is asleep or make the last 40% of the battery life last longer, but frankly the Android system does a pretty good job of doing this by itself. You're not really going to have much effect. SetCPU is mostly useful for overclocking (which we can't do yet), and the underclocking is fool's gold for battery life. If you want a phone with 800MHz CPU that lasts for days then get a LG Phoenix. No point in paying extra for a Pantech Burst to have it run at 1/2 speed. That's like buying a Corvette and then disconnecting half of the fuel injectors.

I have some ideas for software changes to Android OS that would radically improve battery life, but there's not much the user can do about this. And I am not in the mood to try and fix it myself. Google will figure it out one of these days.