[KERNEL][4.0.3] Limited voltage charging for battery-saving paranoid and developers

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This is a stock kernel for GSM Galaxy Nexus 4.0.3 with the following properties:

• Root access with adb (a.k.a. insecure)
• Charger is modified to stop charging at 4000mV and > 80%, and start charging again at 3990mV or < 80%.

Rationales:

• Stock kernel: I value compatibility and stability. While the various mods and new features are undoubtedly very useful for many people, some of them are not well tested which results in lower stability. That is not to say stock Android is extremely stable (it is not), adding new features on top of which very often increases the likelyhood of crashes.
• Limited charging: As a developer, my phone is virtually plugged in the computer all the time. As many of you are aware, leaving the phone charged greatly reduces battery life (Ref). This kernel frees you from having to unplugging and plugging in the phone repeatedly in fear of destroying your precious battery.

Visible differences:

• Charging percentage will not increase after the phone is charged to 80% or more.
• The phone never reports full charge, even if it's charged while being turned off. That means battery stats can accumulate which, after a while, makes it practically useless as the diagram is too compressed. This is a plus to me as I can see how I manage the battery over time, although I can make an alternate version which reports full charge whenever the phone stops charging under requests.

Perhaps I'm the only one who is paranoid about keeping battery charge between 10-90%, I wouldn't be surprised if no one is interested it this at all.

The kernel can be flashed using Odin or fastboot. If someone wants a CWM-flashable zip let me know.

Cheers.

You could have simply used my BLX mod.

Originally Posted by Ezekeel

You could have simply used my BLX mod.

Glad to know I'm not the only one. When I was using the SGS2 I spent quite a bit of time looking for such mod to no avail. Searching for "android|galaxy nexus limit charging voltage" turned up lots of posts about changing kernel voltage which wasn't what I wanted.

I like to keep the kernel close to stock, but thanks anyway .

Hey, an idea to you devs: what about a apk that schedules the charge limit? for example, if you use to charge your phone at night and you wake up at 7 that app could charge the phone @ 60% and at 6 start charging'till it reaches the 100%
With ezekeel BLX mod it should be easy to schedule modifying the file, but i have no idea on programming nor cron

Originally Posted by Guzmanus

Hey, an idea to you devs: what about a apk that schedules the charge limit? for example, if you use to charge your phone at night and you wake up at 7 that app could charge the phone @ 60% and at 6 start charging'till it reaches the 100%
With ezekeel BLX mod it should be easy to schedule modifying the file, but i have no idea on programming nor cron

You can do that with Tasker, it is a bit on the heavy side but saves having another service running in the background while leaves the possibility to do a lot more. I'm not aware of other light-weight but user friendly solutions for managing scripts, perhaps others could chime in.

Originally Posted by Ezekeel

You could have simply used my BLX mod.

agree with ezekieel...his Battery Life eXtender (BLX)do the same thing(via file /sys/class/misc/batterylifeextender/charging_limit default 100),without give up at all the tweaks,oc,color control etc. try that if you want.anyway thanks for the work,personally it not interest me,but certainly someone will find it usefull!

Originally Posted by fnf

This is a stock kernel for GSM Galaxy Nexus 4.0.3 with the following properties:

• Root access with adb (a.k.a. insecure)
• Charger is modified to stop charging at 4000mAh and > 80%, and start charging again at 3990mAh or < 80%.

Rationales:

• Stock kernel: I value compatibility and stability. While the various mods and new features are undoubtedly very useful for many people, some of them are not well tested which results in lower stability. That is not to say stock Android is extremely stable (it is not), adding new features on top of which very often increases the likelyhood of crashes.
• Limited charging: As a developer, my phone is virtually plugged in the computer all the time. As many of you are aware, leaving the phone charged greatly reduces battery life (Ref). This kernel frees you from having to unplugging and plugging in the phone repeatedly in fear of destroying your precious battery.

Visible differences:

• Charging percentage will not increase after the phone is charged to 80% or more.
• The phone never reports full charge, even if it's charged while being turned off. That means battery stats can accumulate which, after a while, makes it practically useless as the diagram is too compressed. This is a plus to me as I can see how I manage the battery over time, although I can make an alternate version which reports full charge whenever the phone stops charging under requests.

Perhaps I'm the only one who is paranoid about keeping battery charge between 10-90%, I wouldn't be surprised if no one is interested it this at all.

The kernel can be flashed using Odin or fastboot. If someone wants a CWM-flashable zip let me know.

Cheers.

Source code?? It has to have a link.
Since you modified the kernel

Originally Posted by Mikey

Source code?? It has to have a link.
Since you modified the kernel

Not much to speak of tbh. Here is the patch. You can build it from the stock branch 4.0.3_r1 . I changed the compilation flags so it better matches Cortex A9 but I'm sure there are rooms for performance improvements.

GLaDOS kernel has this value configurable as well so aside from being stable, this kernel is worse all around .

I assume you meant 4000 mV, not 4000 mAh? Considering that not even extended batteries I've seen exceed 3500 mAh?

Originally Posted by Entropy512

I assume you meant 4000 mV, not 4000 mAh? Considering that not even extended batteries I've seen exceed 3500 mAh?

Post amended, thanks .