Do all kernels kill battery life?


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  1. biblefreak

    biblefreak Well-Known Member This Topic's Starter

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    So I am on my 2nd kernel now other than stock. I tried netarchy .18 and currently using kings 9 bfs. I am running stock rooted froyo. The stock kernel gave me the best battery,both netarchy and kings kernels have given better performance. Is there a best of both worlds, i.e. a kernel that gives better performance over stock AND better battery life? With the netarchy kernel I used 25 percent of my battery in 2 hours from a full charge. So far with kings I have used 10 percent in 30 minutes from full charge! This compared to stock which was 90 percent over 20 hours.

    Any ideas or suggestions?
     

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  2. WaynesNside

    WaynesNside Well-Known Member

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    Same here, seems I can almost just watch my Batt drain.
     
  3. novox77

    novox77 Leeeroy Jennnkinnns! VIP Member

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    Your results are atypical. Did you wipe cache and dalvik cache before flashing custom kernels?

    One of the advantages of custom kernels is the disabled perflock, which allows you to throttle your CPU. You can use setCPU to control how to throttle. By throttling down to 245mhz when your screen is off, you can see huge battery savings while the phone is not in use.

    Just be careful about measuring battery usage from full charge. The indicator is not accurate especially when the battery is near full charge.

    I'd also be a lot more scientific about testing battery life. Make sure you don't change any settings, radio toggles, etc on your phone while testing the various kernels. Make sure you're in the same physical position, since reception makes a world of difference in battery life. Make sure the battery life is below 90% when you start testing. And clear those caches between each flash.
     
  4. biblefreak

    biblefreak Well-Known Member This Topic's Starter

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    I admit to my method being slightly off as my stock kernel battery life was measured over a 20 hour period where netarchy and kings were observed over much shorter periods of time. All other "controls" are good though with the same radios running at home with normal use. I will watch and see what the difference is over the next 20 hours.
     
  5. WaynesNside

    WaynesNside Well-Known Member

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    I didn't clear my caches when I flashed my Kernel. Is that something worth doing at this point? Will it make that much of a difference now?
     
  6. UTnick

    UTnick Well-Known Member

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    kernel source code isn't released with the bits for power management because those bits are proprietary. as such -- the kernel you're using may not do the scaling that a stock kernel would and using something like SetCPU to manager your power usage when the phone is not in use may be a must.
     
  7. exBBuser

    exBBuser Well-Known Member

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    Yes, wipe both of your caches and reflash the Kernel. When you get a chance wipe your battery stats an calibrate your battery.
     
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  8. biblefreak

    biblefreak Well-Known Member This Topic's Starter

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    I cleared both the cache and the Dalvik cache before using each kernel. Also using SetCPU with 2 profiles, one to limit cpu to 245mhz when screen is off and another with a higher priority to not throttle if it is charging so that I can use wireless tether without throttling the cpu if it is plugged in to my laptop. Scaling is set to on demand with min 245mhz and max 998mhz.

    I am trying not to account for short term battery usage, but it is discouraging when netarchy lost 25 percent after 2 hours and currently on kings which has dropped 25 percent in merely an hour and a half!

    Will continue to monitor and see what happens.
     
  9. biblefreak

    biblefreak Well-Known Member This Topic's Starter

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    Something else. Currently using kings kernel and under battery status I see Up Time and Awake Time both show the exact same amount of time at 4:05:49! When I was using netarchy and stock the Awake Time was significantly less than Up Time.

    Any thoughts?
     
  10. exBBuser

    exBBuser Well-Known Member

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    Something is running in the background.Check ur running apps.I believe that you will get better results with Kings if you change your governor to conservative. Is this the BFS or the CFS Kernel u running.
     
  11. biblefreak

    biblefreak Well-Known Member This Topic's Starter

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    BFS. I will try changing to conservative for the next round of tests!
     
  12. novox77

    novox77 Leeeroy Jennnkinnns! VIP Member

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    Excellent point. However, both netarchy and kingx kernels are modifications of the stock kernel's source code, and without setCPU in place, the stock scaling governance is still there.


    Before you try to fix this, flash another kernel and/or stock kernel and see if awake = uptime still, particularly with the stock kernel, since you seem to see the best battery life there. Based on what I've seen, the facebook app is the guilty culprit for awake times, although i wouldn't rule out some other app/cause either. But I really doubt the awake time is caused by the kernel.
     
  13. WaynesNside

    WaynesNside Well-Known Member

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    Do you wipe both caches and then flash Kernel right away or is there rebooting necessary in that process?

    Just want to take the right steps.
     
  14. novox77

    novox77 Leeeroy Jennnkinnns! VIP Member

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    you do everything from RA recovery. Go to "Wipe" and from there, you will have the option to clear cache, and clear dalvik cache. once done, stay in recovery, but go to the install ZIP from sdcard option. Choose the kernel and install it. reboot and you're done.

    You can use clockwork as well, but there's this persistent rumor that it doesn't clear dalvik cache correctly. I have yet to see any evidence of this. Kinda like the ban of cell phone use on airplanes. Most likely it does no harm, but they ban it anyway just in case :)
     
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  15. surfologist87

    surfologist87 Well-Known Member

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    Thats a federal offense you know!
    Didnt myth busters did an episode on that and they couldnt even do it, they had to keep the plane on the ground?
    I dont remember lol
     
  16. novox77

    novox77 Leeeroy Jennnkinnns! VIP Member

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    people fall asleep before takeoff and leave their phones on all the time. Or it's left on in a carry-on. We're not seeing planes falling out of the sky left and right because of this :)
     
  17. WaynesNside

    WaynesNside Well-Known Member

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    Thanks once again, Nov that's pretty much what I did...didn't wipe though. Just cleared the caches and re-flashed the Kernel.
     
  18. surfologist87

    surfologist87 Well-Known Member

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    Oh, yeah im definitely sure it happens more than we know. With as much air travel as there is, id love to know how many phones are actually left on..lol
     
  19. Putty

    Putty Well-Known Member

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    We gotta just live with the fact the battery is shit. I, too, have tried multiple kernels and nothing has helped. I am also using setCPU. It doesn't really help. I can go to bed at 100% and wake up in the 70s. No use at all with underclocking...sucks!!
     
  20. novox77

    novox77 Leeeroy Jennnkinnns! VIP Member

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    your battery life is not a lost cause. All this tells me is that the root cause of your battery drain has nothing to do with your kernel choice or setCPU settings. Once you can find the true source of the drain, you will be home free.

    Tonight, when you go to bed, put your phone in airplane mode and disable wifi, gps, bluetooth, etc. Note: you won't receive any calls or text. But this will rule out radio as the cause of your battery drain. Report back the next day and let me know how your battery did. Then we'll try some other stuff :)
     
  21. WaynesNside

    WaynesNside Well-Known Member

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    I wanted to post back up in this one. I did what was suggested on this page. I took SetCpu off though because of issues. With moderates use some YouTube vids a bit of tethering and messing with apps and playing around with the phone I hit a lil over 17 hours and I was still at 11%.
     
  22. tsipa

    tsipa Well-Known Member

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    If you are running a HAVS enabled kernel such as the King's, turn your SetCPU profiles off. If you are running this type of kernel, using profiles negates the benefits of HAVS. You should only be using the first page in SetCPU to set your overclock frequency and perhaps change the governor to conservative for better battery life. I was an avid user of profiles myself until I took King's advice and tried running without the profiles, the result was much better performance and slightly better battery life.
     
  23. Putty

    Putty Well-Known Member

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    OK, I just found this thread again. I will do this tonight and see what happens. I'll charge to 100% and shut it all off.
     
  24. Putty

    Putty Well-Known Member

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    I took my profiles off yesterday cause i'm running Kingz #9 and I swear my battery got worse. I turned them back on. Although #9 does not mention HAVS

    Kernel #9

    - Finally released
    - Board files fixed to allow lower undervolt
    - Undervolted to 825Mhz for safe frequencies
    - Higher clockspeeds WILL be more stable now
    - Compiled CIFS module per request
    - Regulator tweaks
    - Removed some bloat
    - Now using ondemand governor by default, feel free to change it
    - Battery charging tweaks (like my inc kernel)
    - You guys are going to like this one
     
  25. tsipa

    tsipa Well-Known Member

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    All of the King's 2.6.32.15 kernels have HAVS. Are you using the conservative governor? I could have sworn that my battery life was worse after I took off profiles but after further testing the change proved worthwhile.
     

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