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Root [Virgin Mobile] Battery Life/Kernel Tweaks Discussion Thread

I will start things off by stating that I have a ZeroLemon 7000mAH battery, which I absolutely love! I am able to go five or six days, roughly, on a single charge. This is in conjunction with dkp kernel, running Carbon ROM. I use the app Andromizer Pro to tweak my kernel settings; TricksterMod (Donate version) is also quite nice for this purpose. My current settings are as follows (remember, YMMV, and no two people use their phone for the exact same purposes; I do lots of texting, Tapatalk, and Google+, but no gaming or videos):

CPU Scaling Frequency: 108 MHz minimum, 1512 MHz maximum
CPU Governor: freelunch
I/O Scheduler: zen
Multicore Power Saving: 2 Core
ZRAM enabled
TCP Congestion Control: reno
Read Ahead Buffer Size: 2048 for both internal and external

Under the built-in ROM features, at Settings/Performance, I use the Performance Profile, with Purging of Assets and Kernel Samepage Merging enabled under Memory Management.
 
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I've been very happy with the genuine Samsung extended battery kit -

Amazon.com: Genuine Samsung Galaxy S3 i9300 Extended Battery Kit 3000mAh + White Cover: Cell Phones & Accessories

It was about $50. It's made by Samsung, so I didn't have to worry about the quality of third party manufacturers. It increased my battery capacity by a third and came with an extended back cover to fit the bigger battery. It all fits the S3 perfectly. It makes the phone slightly thicker, but I find it easier to grip and it feels more substantial now. I know an increase of around 30% doesn't sound like a lot, but I can now go a full day from sunrise to sunset without ever having to worry about running out of power again.
 
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Undervolting is already included as well in dkp kernel, but it is fine to go lower if you feel the need. Be careful though, undervolting can have the reverse effect on battery life from what you are trying to achieve-if the phone isn't receiving enough power to make things work (in very basic terms, this is obviously not the technical description based on the physics of a battery and power transfer!) then it will force the battery to do more in order to function properly, which equals battery drain. I've gone as low as -100 across the board with no ill effects, but remember, no two users will get the same results based on user differences, so what works for one can be detrimental for another. Haven't messed with voltages myself for a while, still getting the usual five to six days out of one charge on my ZeroLemon.
 
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what about performance is freelauch better than iinteractive

Like a lot of things in the world of Android, there isn't necessarily a "better," it is a matter of what works for you and what doesn't. No two users are the same, in terms of what apps are installed, how they use their phone, etc. Personally I also like the freelunch governor (see post #2 in this thread), but what works well for me and the way I use my phone may not be someone else's cup of tea. Best thing to do is to apply various combinations, one battery cycle at a time, and see what works well for you under normal circumstances. One thing that will generally apply, however, to most users, is lowering the upper frequency from 1512, as any device with more than one core (ours is a dual core), is not going to see significant performance change with a slightly lower frequency, but this should help battery life to one degree or another.
 
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What benefits are gained by bumping up the Read Ahead Buffer Size?

It's an efficiency aspect, so your battery isn't working too hard because of constant CPU drain (I don't know a more technical explanation). You can use ROM Toolbox Pro to benchmark your read ahead values (it will test each possible value and show you the performance metrics associated with each one). On my phone, 2048 was optimal for both internal and external.
 
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I'm currently in the process of doing some battery tweaks. There is a lot of good info out there, but it takes a lot of patience. If you do a search for "android governors" there are a bunch of links explaining what each one does and the pros and cons.

Right now, I am trying to see if the Interactive governor with my settings or freelunch governor is better.

There isn't too much info about the freelunch governor so i can't make any changes to it as well as I can with interactive.

My last run, I was getting about 5.5 hours screen time, but this is about twice as much as I was getting.

Just do some good research and have some patience and you'll be saving some battery in no time!
 
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Is it OK to flash a kernel on a stock ROM then flash back to CM11? Just wanna make sure that CM11 won't screw with the kernel. I'm on CM11 right now. Would have to flash back to stock to flash a kernel but if it would help I'd definitely do it. Just need the info first. Thanks for any help.

Any time you flash a custom kernel, if you then dirty flash a new nightly or change ROM's altogether, the custom kernel will be overwritten by the kernel that is built into whatever ROM you most recently flashed. Also, kernels for TW based ROM's are vastly different from kernels built for AOSP, you can't interchange the two. So, if you intend to flash a custom kernel, make a Nandroid right before, that way if you don't like the custom kernel, you just restore your most recent backup and the custom kernel will be gone.
 
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Any time you flash a custom kernel, if you then dirty flash a new nightly or change ROM's altogether, the custom kernel will be overwritten by the kernel that is built into whatever ROM you most recently flashed. Also, kernels for TW based ROM's are vastly different from kernels built for AOSP, you can't interchange the two. So, if you intend to flash a custom kernel, make a Nandroid right before, that way if you don't like the custom kernel, you just restore your most recent backup and the custom kernel will be gone.

Any good kernels that work with CM11?
 
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I can't believe that I haven't browsed some of the other carrier forums on XDA for the SGS3 until tonight to look for more d2lte/unified options that don't have threads in the Sprint forum. Found several ROMs, either new to us or updated versions of what is available on the Sprint forum, along with a new kernel. The kernel is from Quantum ROM; the ROM does flash, but being closely based on CM11 does have the current data connectivity issues (for me, LTE connects but 3G refuses). However, the kernel is available as a separate download, so I have flashed that on latest LiquidSmooth, will let it run for a while and see what happens.
 
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I can't believe that I haven't browsed some of the other carrier forums on XDA for the SGS3 until tonight to look for more d2lte/unified options that don't have threads in the Sprint forum. Found several ROMs, either new to us or updated versions of what is available on the Sprint forum, along with a new kernel. The kernel is from Quantum ROM; the ROM does flash, but being closely based on CM11 does have the current data connectivity issues (for me, LTE connects but 3G refuses). However, the kernel is available as a separate download, so I have flashed that on latest LiquidSmooth, will let it run for a while and see what happens.

Excellent. Let us know how you like it.
 
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