[Optimus One, P500, V General] marcomarinho:
Disclaimer; This does not damage your phone at all or fry/mess up your cpu. On the contrary, it helps it by not running at full capacity all the time resulting in less stress and increased battery.​

All credits goes to SuperAce609. I only share with you because this helps a lot. Original Thread: http://xdaforums.com/showthread.php?t=1447938

This method works universally for any Android phone you're using. But you'll need ROOT for Set CPU.

IMPORTANT: The newer versions of SetCPU might prevent your phone from entering deep sleep. Download version 2.24 from the following link which is the one with no problems and completely works 100%.

http://xdaforums.com/showthread.php?t=505419

The Ace sucks in battery life. We all know that. And on 3G? Don't even mention it. But here's a fix, ever tried Under clocking instead of Over clocking?

Someone brought it up on a thread a couple of days ago and I have to spread the word, that works wonders. Got my Ace running on 245 min and 806 max and a different Screen Off profile. And now from the morning till 6PM in the afternoon, its just 61% AND recorded a 7 minute video/took pictures.

Battery was the only issue I had with my Ace. But now that its fixed, I love it :D

When screen is on:

MAX 806

MIN 245

Ondemand governor (This governor bumps up to max when needed but spends most time on the min freq. Best battery saver.)

When screen is off:

MAX 320

MIN 122

This way, you have a beast quick phone when you're using it, and the best battery saver when you're not!

This is what CPU spy should look like when you're done:

NOTE: Turn off Autosync from the settings. It's only used to sync your gmail and contacts and such. You can manually sync when you add a new contact and since I don't use gmail, I refresh manually whenever I do. 3G is the worst battery killer so this will help a lot.

SetCPU: http://xdaforums.com/showthread.php?t=505419

Specific instructions for those that can't get it to work!:

On SetCPU:

Click Add profile

Where it says Profile, select it and tap "Screen Off"

Set the frequencies you want in use while screen is off (If you want just one frecuency, put both sliders on the same number)

Set priority (in case you have other profiles, otherwise don't bother)

Select governor (Won't really matter since cpu is gonna be running at 1 frecuency)

Tap save

Go back to Profiles tab at the top, then tap Enable at the top left to make the profiles work.

For a list of most governors detailed; check out this thread! http://xdaforums.com/showthread.php?t=1242323

To check if its all working, install CPU spy from the market:

https://play.google.com/store/apps/...251bGwsMSwxLDEsImNvbS5idmFsb3Nlay5jcHVzcHkiXQ..

Battery Calibration

1. Turn your phone off

2. Leave charging over night

3. Turn it on

4. Leave it charging for half an hour

5. Download this app https://play.google.com/store/apps/details?id=com.nema.batterycalibration&feature=search_result

6. Open it and press calibrate battery

7. Discharge your phone down to 0% during the day

8. Charge back up to 100% NON-STOP.

This is to make sure you're using your battery at 100%. Only do this after you flash a new rom.

The worst battery killer is 3G itself. No matter how much you try to optimize battery and underclock, if you have 3G on, you're gonna have a bad time. MAKE SURE Autosync is disabled.

Thanks to QNBT for the AutoSync off and new profile settings hint!