Adventures in achieving 5+ hours

So far I've managed to get my laptop running 3.5-4.5 hours running either Windows or Linux. (general usage)
I got the longer battery life by changing some of the hardware. The biggest difference came from a larger capacity battery (7200mAh) and swapping out the 5400rpm HDD for an SSD.

The current specs for the Laptop (Acer 5570) are:
Intel Core Solo > Intel Core 2 duo T7200
1GB DDR2 > 4GB DDR2
5400rpm 80GB Hitachi > 64GB Kingston SSD
Windows XP > Lubuntu 11.10/Windows 8 Developer Preview. (both 32-bit)

I decided to go with Windows 8 Developer Preview over Windows XP for 2 reasons.

1. Windows XP is a 10 year old O/S and lacks functionality compared to Vista & 7 (yes I prefer Vista over XP)

2. Windows 8 Developer preview is aimed towards tablet PC's.
So my assumption is, that it would be better optimised for a mobile platform
(It's an assumption only, I'm not basing it off any facts)


The optimisations I've made in Windows so far have been.
- Disable unused devices in device manager.
- Disable non-neccassary services.
- Some theme effects.
- Changed the power scheme settings.
I didn't disable the 'aero look' for a couple reasons, 1. I like it, 2. I can't.

I've also changed the CPU voltages via software, because the settings aren't available in the BIOS.
(I'll link the software I used when I get a chance)

From memory the T7200 idles at .950v, and maxes at 1.1750v under load at 2.00ghz
The software doesn't allow me to lower the minimum voltage, but it does allow me to change the maximum voltage. I have it currently set at 1.1v under load.

I haven't tested whether it's stable at 1.1v for an extended period of time. I think I'll favour battery life over stability though.

As for my efforts on the Linux front. I went with Lubuntu because it uses a 'lighter' desktop environment. The LXDE desktop requires less RAM and puts less load on the CPU.
Which all means less strain on the battery.

I also decided to start compiling my own kernel optimised for the Core 2 duo, along with a couple of other changes.
- I enabled PAE (because the system has 4GB of RAM)
- Changed the kernel timer to 100hz
- Disabled some compatibility with AMD processors.

I used the latest kernel (at the time of this posting) from kernel.org, 3.1rc4 3.1 mainline . Lubuntu/Ubuntu 11.10 uses the 3.0 kernel.

Sorry for the long post, I should have started a thread earlier.
Thanks for reading.

TL;DR
Buy massive battery.


EDIT:
Bit of an update for those interested. I was finally able to compile the kernel, I ended up doing it at home. The PC's at work are just too slow, it took more than a few hours and they didn't even complete the compile.
My PC only using 3 cores completed the compile in less than an hour.

I haven't tested the kernel on the laptop yet, but the kernel does seem to work.
I've also found a command that's meant to have a decent improvement on battery life for those that are using a Ubuntu (or Ubuntu based distro) with kernel 2.6.38 or up.

pcie_aspm=force

You can read about it here:
http://www.phoronix.com/scan.php?pag...inux_epb&num=1
Edited by Cipher - 11/3/11 at 5:55pm

The laptop's motherboard has a socket for the CPU just like a desktop motherboard, well mine did at least.
Although I literally had to take the laptop completely apart to change it.

Maybe I should have taken pictures and made up a little tutorial.
Oh well, I'm happy to give anyone tips if they ask.

I still plan on trying to get 5 hours, I'll update my post with updates, though I'm running out of ideas. (Compile and optimise the software I use?)

I've yet to try the new kernel. I started compiling it at work, it was still going when I left it.
I'll be able to see if it works tomorrow.

The kernel compile failed
I used Linux Mint inside a virtual machine to compile the new kernel, but the virtual disk ran out of space.
At least the configuration is fine, I'll just have to adjust the virtual machine and re-do the compile.

To be honest I don't know.
I changed almost everything at once, saved me having to take it part again.
So I wouldn't be able to tell you. Sorry.
The most noticeable change was from a bigger capacity battery, which I got for about $40. So if I had to pick between an SSD or a Larger battery. I would go battery.
Obviously I did both

That's crazy.
Forget optimisations. Just throw a bigger battery in!

For those interested. I managed to successfully install the custom compiled kernel for my Lubuntu install.

I haven't noticed any significant difference, though I haven't used lubuntu for long to be able to tell
Windows 8 still has a longer battery life over lubuntu. Roughly 3-3.5 hours for Lubuntu, Windows 8 - 5 hours.
However those figures are while the laptop is running idle. It's obviously lower when under load.

I've pretty much run out of ideas on how to improve the battery life. So I'm open to ideas.

As a side note I have to give credit to the guys at Apple. When I was using a Macbook I was getting awesome battery life, I didn't have to do anything.
That Macbook was one of the core2 duo models aswell, so they would be even better now.