What's the free way to do it?
What we really need is for someone to do this with the different kernels on i9000:
Matrix kernel would be nice!
Which kernels do we feel are particular good on battery life? I'd be happy with a 30fps screen heck to save 10% battery!
For reference and a reminder, from NexusS research (bedalus did some fascinating work):
#1 - With screen on, if the processor is Idle, 100MHz saves the most power.
#2 - Regardless of your choice of governor, even with extreme undervolting, you are not going to be able to increase your battery life by more than 2%. (Click here for explanation.)
For the instability introduced by UV, it seems a 2% increase in battery life isn't really worth it! REMEMBER rebooting uses so much power, a single one would more than undo any savings made by UV.
#3 - The most power saving governor is Ondemand. If you need a high performance governor, use smartassV2, which offers some battery savings.
#4 - This is one point that everyone ought to know, but I'm including because many people seem to believe in myths: if the screen is off, and the CPU is not active, neither deep idle nor UV will have any impact on battery life.
#5 - The matr1x kernel by mathkid95 mainly saves power through UV of the INT voltages. You may need to raise these if you have freezes/reboots with your phone (in addition to raising the ARM voltages). I found that a maximum of 1 mA can be saved through INT UV, regardless of whether the CPU becomes idle (or with screen off in deep idle), so this is a constant saving. However, it is a very small saving, and doesn't apply if the phone is asleep. Remember, reboots cost more juice than UV can ever save.
#6 - If you have an amoled display, black saves a great deal of power. After that, red. If you have a black and red theme, this is saving you power!
#7 - If you are determined to UV, I found that my phone would become unstable with UV settings that were fine when the battery was fully charged. So check what UV your phone can handle when your battery is nearly empty. Again I say: Because of the high likelyhood and massive battery drain that comes with a reboot, I highly recommend you DO NOT USE EXCESSIVE UV. Also remember, even with extreme UV, you will not increase battery life more than 2%
#8 - I found that with bluetooth or GPS preventing the TOP=OFF state, there was no additional power saving from Deep Idle, i.e. the TOP=ON state does not save power.
#9 - Kernels with the 65 fps hack will cause the screen to drain about 10% more power compared to the usual 56 fps.
#10 - Conservative does not save power! For further details and exceptions, refer to my new thread: here. (ondemand is best)
#11 - This is just general advice: if you are having very poor battery life, have you tried turning auto brightness off? And if you've got no reception, you might as well be in airplane mode, because searching for reception also eats battery.
#12 - If your phone can't handle OC (or UV for that matter) it's because components in general are built to cost, which means factoring in tolerances, and every chip is made as cheaply as possible within the specified tolerances. Outside of those tolerances, whether your chip can cope or not is unfortunately down to the whether you got lucky with the individual device that dropped off the manufacturing line.