Easiest way to increase battery life - Undervolt

[PowerThroughLove]

For those of you who are rooted and want to try a quick and easy way to increase battery life - try undervolting. Its exactly what it sounds like - you use fewer volts to run your phone at a particular CPU speed. Fewer volts = lower power draw = longer lasting battery life ( " for free " in a way).

I didnt see a thread in here about voltages people are using (excuse me if I missed it) so thought I would make a place to post your current voltages. Current I am running ImoseyON Lean kernel 1.4 with the following voltages:

1200mv @ 1.2 ghz
1000mv @ 920mhz
900mv @ 700mhz
700mv @ 350mhz

I am mostly focusing on the 350mhz setting (it is where the phone is 95% of the time after all). I can run it at 675mv but it crashes at 650 and I usually like to go one step above the absolute minimum.

 

[Strafe]

I like the idea a lot ... still, can you quantify how much battery savings you actually see as a result of undervolting?

Not throwing stones here; not trolling. I undervolt my Samsung Epic but that's only part of my battery extending strategy.

Thoughts? Ideas? Data?

 

[burwil]

My last phone, the DroidX, ran Sensei Mod 602 which undervolted the battery. It very clearly had longer battery life.

Sent from my Rezound via Tapatalk.

 

[CrazyRussian007]

From what ive read, undervolting precess is expensive and switching back and forth takes some cpu power, which in turn, reduces battery life. On various forums ive noticed that kernel developers switching to develop kernels that use 90-95% of stanrdart voltage and they take options out for selectable voltages. Great read here: [Kernel]LTE[3.0.14]ICS4.0.2/3/UV,GPU+CPU OC,CIFS,SLQB,OTG,FIOPS(v0.0.8)[Jan-07] - RootzWiki - Page 36

 

[digitalslacker]

Undervolting can and does help with battery life.

But, if you stop and consider that the vast majority of your battery usage is the screen first and probably wireless data second, you probably won't notice drastic increases.

Everyone uses their phones differently and every little bit does help so maybe some will notice it.

I personally gave up on tweaking the phone to try to optimize battery a long time ago and went out and bought about 4 chargers and just put them all over the place and stopped worrying about it.

One trick I do use is the Battery Calibration app, I run it post a rom install (or update) and get crap for battery life on Day 1 but by Day 3 I'm getting 9-10hrs on a charge. But, usually after about 3 days there's another ROM update out and I have to repeat the process

 

[5h4un360]

How does one undervolt? I'm running Franco Kernel

Sent from my GalaxyNexus using Tapatalk

 

[nsurg]

How does one undervolt? I'm running Franco Kernel

Sent from my GalaxyNexus using Tapatalk

I don't exactly "have my finger on the pulse" of all recent things, but I think he said in his kernel that he was not going to give undervolting options "for reasons extensively discussed" or something like that, and that his kernel was already undervolted a bit. Hence, there is no option to change voltages on his kernel and this decision was intentional.

Without any great personal insight, I am also using this kernel because it seemed to be one of the more actively discussed at xda.

Perhaps this goes back to the post above, referring to less options for undervolting having some merit?

 

[mikestorm]

Undervolting can and does help with battery life.

But, if you stop and consider that the vast majority of your battery usage is the screen first and probably wireless data second, you probably won't notice drastic increases.

Does undervolting help with the power draw of the screen? I have the screen at the lowest bearable brightness, but hands down it's still always responsible for over 50% of my battery drain. As the other components effecting drain gett more efficient, not surprisingly the screen % contribution on battery drain has been increasing over the past few weeks.

 

[digitalslacker]

Does undervolting help with the power draw of the screen? I have the screen at the lowest bearable brightness, but hands down it's still always responsible for over 50% of my battery drain. As the other components effecting drain gett more efficient, not surprisingly the screen % contribution on battery drain has been increasing over the past few weeks.

I've never seen it associated with the screen, I could be wrong though. Everything I have read about under-volting pertains to the processor.

Either way we're not talking about huge numbers here, if you drop the voltage too far you have problems. and some phones are less than forgiving when it comes to tweaking the voltage. So everyone's mileage will vary.

There's no question that battery tech isn't advancing as fast as the power requirements of these devices and I don't believe any amount of kernel tweaking is going to have significant enough improvements to counter that. If it did, you'd seen OEMs including those tweaks in stock. Even back when I used the Nexus S and kernels started supporting deep sleep, the gain was marginal at best. Maybe an hour more a day at best.

I'm not knocking the devs that are working on this stuff, i'ts good, necessary work. I just don't think the gains realized are big enough to make any real difference.

My approach is to just have lots of charging options. Any time I'm in one place for more than a few minutes the phone gets plugged in and I never have to worry about battery.

 

[Masheen]

I don't exactly "have my finger on the pulse" of all recent things, but I think he said in his kernel that he was not going to give undervolting options "for reasons extensively discussed" or something like that, and that his kernel was already undervolted a bit. Hence, there is no option to change voltages on his kernel and this decision was intentional.

Without any great personal insight, I am also using this kernel because it seemed to be one of the more actively discussed at xda.

Perhaps this goes back to the post above, referring to less options for undervolting having some merit?

I'm using Franco.Kernel as well. It is the best kernel i have used for battery life. It is slightly better than lean kernel. There are a number of tests for it on the Xda forum showing this.

Search Franco in the app market and download "Franco.Kernel Updater app" Its a small price to pay to use his work and provides some killer extras in the app. One being the option to OC/UC, there is an option under kernel settings to turn off CPU_1 when the screen turns off and activates it on screen on. This is an amazing option and saves a ton of battery life. In his latest update he adds the ability to change the gamma and coloring of the Nexus and of course there is the option to boot strait into recovery.

[KERNEL][GPL][12 JAN - #12] franco.Kernel | 4.0.3 | OC | TUN | INIT.D | COLORCONTROL - xda-developers

I am also using Redemption ROM v1.0.3 put out by OhHeyItsLou. It is amazing. He tweaked the speed of all the animations and made the app launcher incredibly speedy. It is one of the only ROMs with a preserved ICS look. He didn't change any of the aesthetics. He kept ICS fully in tact and did some great work under the hood. Check him out guys: [ROM] Redemption Rom ICS v1.0.3 *UPDATE* Jan 10th 7:30pm EST - RootzWiki

 

[KoukiFC3S]

I was all set on lowering my voltages as low as possible, but from what I've read the Nexus goes into deep sleep when it is on standby.
The deep sleep uses a different voltage than the 350MHz setting, so lowering the 350MHz voltage doesn't improve the standby time much.

I've been using faux123's kernel, which turns off one core when the screen is off. I've been getting great results with that one.