Run a MacBook at full clock speed without a battery

yeroc3103yeroc3103
Posted:
in Current Mac Hardware edited March 2015
I purchased a broken MacBook (Santa Rosa) from Ebay several month ago. I use it as a media center connected to my home theater. The MacBook was dropped and had a broken screen and a beat up case. It was always the eye sore of my entertainment center. I recently decided to put it in a custom tiny enclosure witch is nothing more than an attractive external hard drive case. I got it all together and everything is running great...except one tiny detail. The MacBook underclocks itself to 1200 MHz when the battery is not connected. After much research I discovered this was intentional by Apple and all advice given to me was just put the battery back. I don't have room to put the battery back I just have it laying next to the computer causing the same eye sore I had before. There has to be a way to "trick" the computer in thinking the battery is connected. I wouldn't mind it if 1200 MHz was enough raw power to decode HD h.264 but its not. Does anyone know a way to either directly attach the mag safe adapter directly to the battery terminals or somehow short the pins to simulate a connected battery? Or better yet a software solution?

Comments

  • Reply 1 of 13
    addaboxaddabox Posts: 12,665member
    I would have assumed that if Apple were making the CPU underclock under certain conditions, it would be while on battery, not plug. Forcing it to underclock when plugged in doesn't make any sense.
  • Reply 2 of 13
    tallest skiltallest skil Posts: 43,388member
    Quote:
    Originally Posted by addabox View Post


    I would have assumed that if Apple were making the CPU underclock under certain conditions, it would be while on battery, not plug. Forcing it to underclock when plugged in doesn't make any sense.



    Forced underclock when plugged in with no battery.



    Normal clock when on battery.

    Normal clock when plugged in with battery in.
  • Reply 3 of 13
    addaboxaddabox Posts: 12,665member
    Quote:
    Originally Posted by Tallest Skil View Post


    Forced underclock when plugged in with no battery.



    Normal clock when on battery.

    Normal clock when plugged in with battery in.



    Why the underclocking with no battery/plug? It's not like the battery is buffering the power, or something.
  • Reply 4 of 13
    yeroc3103yeroc3103 Posts: 2member
    My understanding is that the battery essentially acts as a large capacitor. What I don't understand is why the power adapter can't compensate for power fluctuations? My thought is to short the pins on the terminal to simulate a connection?
  • Reply 5 of 13
    addaboxaddabox Posts: 12,665member
    Quote:
    Originally Posted by yeroc3103 View Post


    My understanding is that the battery essentially acts as a large capacitor. What I don't understand is why the power adapter can't compensate for power fluctuations? My thought is to short the pins on the terminal to simulate a connection?



    Interesting, I had no idea that was going on. My guess, though, is that there's actual logical process on that bus (since any capacitor-like function would need regulation and surely be included in the general power management routines), so that just shorting out the pins won't work. Worse, you might damage something, since if the system sees even an unneeded battery as a reserve it's going to be expecting to route power accordingly, not just into a short condition.



    Any chance you could find a small batt of the right voltage that would fit into your enclosure? Or better, maybe someone who can do the circuit calculation better than I could recommend an actual capacitor sized to match whatever the battery was doing?



    EDIT: Aha, I looked around a bit, and seems you may be out of luck. The Apple support page explains that when being stressed, the system actually needs more power than the AC adapter can provide, so it pulls from the battery. So it appears that sustained h.264 decoding on that model may take more juice than the mains can give you-- which means any battery work arounds would just risk killing your motherboard.
  • Reply 6 of 13
    interrockinterrock Posts: 5member


    I may not be an expert, but for me that makes no sense at all. If the Macbook actually needed more power than the AC adapter can provide, then it would never charge while powered on.


     


    If the AC Adapter alone couldn't provide the necessary energy to make the Macbook work, how could it charge the battery while the power is on and the battery is being used? 


     


    There's more. Windows actually works at full speed on a Macbook without the battery, using the AC adapter.


     


    There must be a way to bypass the forced downclock.

  • Reply 7 of 13
    tallest skiltallest skil Posts: 43,388member


    Originally Posted by interrock View Post

    There's more. Windows actually works at full speed on a Macbook without the battery, using the AC adapter.


     


    There must be a way to bypass the forced downclock.



     


    Sure, but don't come whining to Apple when you break your laptop.

  • Reply 8 of 13
    kingofsomewherehotkingofsomewherehot Posts: 4,180member

    Quote:

    Originally Posted by Tallest Skil View Post


     


    Sure, but don't come whining to Apple when you break your laptop.



     


    It's ALREADY broken ! :)


    That was the whole point of the thread! (and piqued my interest for the same reasons as the OP... too bad nobody has figured out a solution yet.)

  • Reply 9 of 13
    interrockinterrock Posts: 5member


    Hey guys, I finally managed to make it work!! Here's how:


     


    1- First download these two kext files:


    SleepEnabler.kext.zip


    NullCPUPowerManagement (32-/64-bit)


     


    2- Go to /System/Library/Extensions


     


    3- Make a backup of AppleIntelCPUPowerMangement.kext and AppleIntelCPUPowerMangementClient.kext and then delete it from this folder


     


    4- Add here the two kext files you've downloaded earlier


     


    5- Open Terminal and do the following:


     


    cd /System/Library/Extensions

    sudo chown -R root:wheel SleepEnabler.kext

    sudo chmod -R 755 SleepEnabler.kext

    sudo chown -R root:wheel NullCPUPowerManagement.kext

    sudo chmod -R 755 NullCPUPowerManagement.kext




    6- Reboot and you're done!


     


     


    If the computer doesn't boot, do this:


     


    1. Hold down the option key while powering on




    2. Choose [Recovery HD]




    3. Open Terminal




    4. Do the following:


     


    cd /Volumes/[volumename]/System/Library/Extensions

    rm -rf SleepEnabler.kext

    rm -rf NullCPUPowerManagement.kext


     


    5- Restart


     


    6- Put AppleIntelCPUPowerMangement.kext and AppleIntelCPUPowerMangementClient.kext back in the /System/Library/Extensions folder 


     


    Voilá!


     


     


    The fans are still on high and I'm not sure the CPU is working properly, but the slowdown is totally gone. Is good to use a software like CoolBook to manage the energy resources from now on.


     


     


    Source: http://forums.macrumors.com/showthread.php?t=1401957

  • Reply 10 of 13
    interrockinterrock Posts: 5member

    Quote:

    Originally Posted by Tallest Skil View Post


     


    Sure, but don't come whining to Apple when you break your laptop.



     


    What's the use of a Macbook that's already broken?


    From here I'd have five options:


     


    1- Pay for the logic board replacement (costs around $900 here in Brazil)


    2- Sell parts on eBay


    3- Stick with Windows


    4- Make it work without the battery somehow


    5- Set fire on it and post a video on youtube


     


    What would you do?  image

  • Reply 11 of 13
    interrockinterrock Posts: 5member


    Did some tests with CPUTest and it turned out ok. The max temperature was 52ºC. 


     


    Still couldn't make the sleep function to work, even with the SleepEnabler.kext. I'll turn off the sleep option until i find a workaround for this. 


     


    I'll keep you updated if something new happens. 

  • Reply 12 of 13
    bernardrillbernardrill Posts: 1member

    Thank you so very much! 

     

    You just SAVED my old MBP!

     

    Created an account just to thank you.

     

    You rule!

     

    Cheers from Brazil!

  • Reply 13 of 13
    iQuentiniQuentin Posts: 1member
    Hi,

    thanks for the trick BUT it didn't worked for me :(

    Config : MBP4,1 without battery (or dead battery stuck at 0%), OSX 10.9.5
    The proc seems to still be underclocked despite the trick. I've tested its speed with Xbench and compared it with the result of a previous test a few years ago : it's still approx. 2 times slower than with the battery on.

    My only doubt is that your link to the NullCPUPowerManagement.kext is dead so i've looked for another one with the same name somewhere on internet. Is your version of this file special ?

    Another weird thing : my fans are old and did a lot (i mean, A LOT) of noise before the battery failed. NOW (that the battery has failed), the fans don't make any noise AT ALL, as if they were off... weird. As if the underclocked CPU knows he don't need the fans so he doesn't use them. Or maybe the fan controller on the motherboard is dead SO the computer underclocks the CPU...
    Anyway, the temperature (with Temperature Jauge) doesn't seem to be abnormally high... which is even weirder !

    If somebody has an idea for my particular case, i thank you in advance.


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