[General Questions and Answers] Product F(RED):
Yup. The reason battery life isn't so great (without tweaks/apps) is 3 reasons:

- Big screen

- 1500 mAh battery

- Processor is running at 998 MHz most of the time

There are a few things you can do to make the battery last much longer:

- Use SetCPU profiles to force the CPU to run @ 245 MHz when the screen goes off (and optionally to lower the max frequency as battery life goes down).

- Collin_ph battery tweak (you flash it and it's removable as well) will automatically adjust the CPU to maximize battery life

- Use kernels with HAVS to allow fluctuation of voltage

I wrote this up a while ago. It's a pretty simple breakdown of the different aspects of kernels and how they work and save battery. Trust me it's nowhere near as complicated as it looks:

Some things to keep in mind:

HAVS

- Hybrid Adaptive Voltage Scaling. This changes the voltage to the CPU depending on a number of things, but mainly it's based on what the phone needs when you're using it. Each CPU frequency is able to take more or less voltage than it needs, rather than a specific voltage for each frequency. You shouldn't use SetCPU profiles when using a kernel with HAVS as they will conflict and the benefits will be diminished.

BFS/CFS

- Two different types of schedulers of the kernel. Most kernels you encounter will come in two "main" flavors (I'll explain why later). BFS stands for Brain **** Scheduler. CFS stands for Completely Fair Scheduler. BFS tends to give greater, but inconsistent performance (not in a bad way though), while CFS tends to give lower latency but less performance. One is not better than the other; it depends on how you use your phone and what ROM you're using. Sometimes BFS will give you both battery life and performance, other times CFS will. BFS is intended for gaming mainly and things that hog the CPU. CFS is intended more for everyday usage (web browsing, texting, music) and focuses more on the system as a whole, as well as being more stable.

Undervolting

- A sub-category of HAVS, the goal of both it is to get the phone to draw as little power as necessary to run, while being both stable and fully functional. Usually, a kernel will come in just 2 flavors: BFS and CFS. But kernels that offer HAVS will come in 6: Aggressive undervolting, Less Aggressive undervolting, and NO-HAVS (3 for BFS and 3 for CFS). Aggressive undervolting tries as much as possible to keep electrical draw to a minimum. Less aggressive undervolting is for phones that start to act up because they're not getting enough power. And NO-HAVS is self-explanatory. Often times, you can get the same result using a NO-HAVS kernel with SetCPU profiles to lower the CPU frequency as battery life goes down.

Collin_ph Battery Tweak

- a service that's installed by flashing a zip in recovery. It tries to optimize CPU speed in relation to battery life. That is, it will lower your CPU frequency as your battery life goes down. It contains a few other tweaks, but mainly that's what it's for. It'll start working as soon as you flash it, but you can tweak it to your liking by going into your Terminal application and typing "batt-cfg". You can disable the tweak through the built in configurator, or completely remove it by typing "batt-rm" and following the prompts.

DO NOT USE WITH A HAVS KERNEL OR SETCPU PROFILES.

Also:

- 2600 mAh Extended battery from Sprint. It's $54 and comes with a one year warranty and 2 back battery doors (matte black and glossy white). You can also get credited back for it if you chat with Sprint online.

There's also a 3500 mAh battery from Seido that everyone raves about.