Folk,
At last found a solution for the battery life issue. Please read the complete reply for detailed explanation.
I have a Mac Book Pro 15 Early 2011 (2.2 GHz Intel Core I7, 4 GB DDR3 RAM), I had upgraded from Lion -> Mountain Lion a couple of days back. I was very disappointed when i saw that the battery life dropped dramatically from 6+ hrs on a full charge to around 2 hrs on full charge.
The activity monitor showed no deviation from the normal. I was very disappointed and was planning to downgrade but then out of curiosity I thought lets go ahead and see what the issue can be. I tried the following,
- Reset PRAM
- Reset SMC
After doing the same, I didnt find much difference may be a few minutes added. But going on further, I realized that people who have done a complete install, I mean a clean slate install are not facing this issue. This triggered a doubt that may be there is something to do with the disk as when left alone suddenly the fan speed used to go up and even we could feel something to the disk. Realizing the same, I did the following verification on the disk using the Disk Utility (Applications->Utilities->Disk Utilities)
-Verify Disk
-Verify Disk Permissions
I found out that there were a lot of warnings that i found in them. The first one gave hard file pointer issue and the second one listed out many library files where the permissions were messed up.
To Repair the same I followed the following steps,
1. Unselect all the types of files in Spotlight (System Preferences -> Spotlight)
2. Run Disk Utility
3. Verify Disk Permissions
4. Repair Disk Permissions
5. Verify Disk
6. Repair Disk Permissions
On the 6th step i got a notification to proceed with disk repair during startup. I hence followed the instructions,
1. Reboot system
2. Press Command + R during boot
3. Select Disk Utility from the option in the menu
4. Verify Disk
5. Repair Disk
6. Verify Disk Permissions (Just to be sure)
If any disk permission erros are found then,
7. Repair Disk Permissions
Reboot the system.
In Spotlight select only the required types of files and then keep the system idle for a while so that the indexes are made by spotlight.
This has really helped with the battery life on my system. As i am typing my Battery is at 92% and shows 8:25 remaining.
I have even realized running safari is using less battery power as compared to Chrome. I would leave it on the users to choose the best. I just wanted to point out that there is affect of the battery life while running Chrome (dont know why).
Last resort for people whos battery problems are not solved by this is to do a complete clean system reinstall of Mountain Lion.
Cheers,
Adhip Gupta