Q: Battery life dropped considerably on Mountain Lion.

good post but honestly i don't think there is any issue with the battery, because of the amount of people complaining, i hope apple fixes this because, they claim that mbp get 7 hours on safari, and currently im on safari and im only getting 3 hours, and my mbp is over heating. this is a major issue , because apple is claiming false statements about there products

sorry for bad writing...

I'm having the same issue - 2012 MBA, 8GB RAM and i7 processor ... my battery life (basic web browsing and doc editing only) is down to 2.5 hours at best.  If Apple doesn't fix this, I'm going to be forced to return the MBA.

The SMC reset gave me back my battery life. It's a temporary fix as I've done this before but can some of you guys give it a try and let me know if it helps you too. Might be some useful intel for Apple as they diagnose;

It's hard to tell if the SMC reset has worked since the machine is off when you test it. However, most macbook's I think will "flash" the light on the green/orange light on the magsafe connnector.

For me, I did it twice, just to be certain.

http://support.apple.com/kb/HT3964. It's easy to get it wrong. You have to hold all 4 keys down and then let go of them all at once.  For me this was ; (Left-Shift, Control, and Option keys and the power button). The light blinked.

I then powered back on (I was fully charged) and my battery life when back to the 6-7hrs.

I have 4 day old MBP retina 2.6/16/512 Fist two days Lion lasted 2 days sporadic use until ML. 

I did a fresh install of ML on 08-02 left unit charging noticed every time I would remove from charger I would be at about 75% within 10-15 minutes each of the 3 times I unplugged it.

Today as I write this I am at 14% and have used it less than 2 hours since unplugging it. 

Now this is my 1st Mac, but I am suprised that when I shut the cover/put it to sleep it seems to drain the battery like it is in use??   And not just a little but but a noticeable amount.

The thing that helped me out of battery problems most of the time is repairing permissions, as one user pointed out on the previous page.

This can be done in disk utility for those who are new to this (I mostly use Onyx btw).

SMC reset sometimes works too but this is only a temporary solution.

I have a solution for this problem. It's strange but for now it looks like a working solution. Consider trying this:

Open Terminal and type

rm ~/Library/Preferences/com.apple.desktop.plist

then: killall Dock

NOTE: This will reset your desktop settings (wallpaper) to default.

I bought a new Macbook Pro Retina. when I got it I charged the battery to 100% then drained it completely and chraged it back to 100% ... in the past I was told that would lead to better battery life. Now last week I took the computer on the road (in the plane) for the first time and so for the first time was able to test the battery performance. Before the trip I installed Mountain Lion but I don't know if the battery performance was any better or worse before the install. But on the trip I realized that the battery performance was 3.3 hours ... I had fully charged the battery before I got into the plane, after fully charging the battery I turned off the Macbook got into the plane and once in the air turned it on. Wifi was turned off, brightness was at probably 40% and right after starting the computer teh battery said that I had about 3.3 hours ... which was mostly correct. On the web site Apple touts 7 hours with wifi. well I don't know what setting they use for that but I don't even get half of that with wifi off.

Same problem here.  I have been running ML since release.  I don't see a lot of CPU burning in the activity monitor, but battery life is dramatically cut.

Same problem for me: vents turn all the time since the installation of Mountain Lion, even if nothing happens on my 2008 MacBook.

I'm still enjoying 7-8hrs on my MBP 13 i7 (2012). I let is sleep with 2.5hrs left on it last night and still had about that much time left this morning.

One of the things I forgot to tell the Apple dude that called, was that prior to installing ML, my brand new MBP was getting REALLY HOT. I looked up a few threads and it seemed normal. I figured the faster processor than my old 2006 MBP just ran hotter. Well, ever since whatever was wrong... got fixed, it hasn't got hot once and is very quiet.

I really have no idea what appears to have fixed mine. It's been about 5 days now and it seems fine.

So, this is what transpired on my machine: I was running Lion on a 2006 MBP. Backed it up, bought a MBP 13 i7 (2012) and migrated the old Lion system over. I didn't notice any battery problems but didn't time it either. If I had to guess, I was getting close to 5hrs with normal use. However, the fans were coming on A LOT and it was getting very HOT consistently.

Cut to ML launch day, I was one of the unfortunate people who had to wait an extra 72hrs to get a valid Up-to-Date code for the free ML upgrade. Downloaded ML and updated. Almost immediately I noticed the battery performance drop to about 2hrs.

Looked up a few threads and tried SMC/PRAM resets but didn't seem to help. Tried a repair permissions which did seem to help, then tried quitting SugarSync, DropBox & Mobile Mouse Server. Quitting these apps had the biggest impact, but the repair permissions could have contributed too, as well as the SMC/PRAM resets.

I don't know if the problem will creep back, but so far, so good and I haven't noticed any heat or noise at all either.

Just got off the phone with an Apple Tech who called me because of this thread (so they are  definitely watching and trying to work on this).  As others have done, I was given a small diagnostic tool to install and grab information for them to look at.  My battery is DEFINITELY kaput and I am going to go get it replaced on Monday (I hope they can do it in the store since the process is easy with the right tools - for the unibody MBPs)

Question is, is it a defective battery made worse by Mountain Lion?  I don't know?  But I do know that things have gotten significantly worse since I installed Mountain Lion.  It is a fix they are working hard on with no real answers yet.  Hopefully with all of the sample data, it will show patterns and allow a fix.

If Apple calls you, work with them and provide the data they request.  It will widen the sample and help with the issue. Keep posting ... they are taking note!

mid-2011 i7 256GB MBA here...

Add me to the list of those who after instaling MoLi and the power-name firmware update have seen shorter battery life. 

In my case, it seems to be down to ca. 2h, where before it was between 4-6h... Also, when plugged in to my Thunderbolt Display, it seems the fan runs continuously and the device is quite warm...

Guess I'm looking forward to OS X 10.8.1 !!

I have the same problem.. after one week my battery only lasts 1,5 hours! MacBook Pro 13" Late 2011 8GB Ram. In one week i have lost 3% of my battery's health! So if there's no patch comming soon my battery will die within weeks. Allready now 3% in a week is way too much.. This macbook is bought in march 2012! and the battery health is 95%!

This is just CRAZY! Is there a Hotfix, or a patch on the way?!

Same here: 13" MacBook Pro mid-2009. Clean install on a brand new SSD, noticed system running very hot while I was re-installing all the apps again and downloading their recent updates. Down to approx 3 hours of battery usage where before it was more like 5 1/2 - 6 hours. SMC reset, PRAM reset, disk permission repair (why there ACTUALLY WERE broken permissions after one day of installing/usage is a question for itself), no changes. Activity monitor shows only 2-5% CPU usage while ideling, Disk usage also looks pretty normal.

To the Apple engineers that are charged with tracking this down: Godspeed. 326+1 repliers will appreciate your work. Hope you find a solution soon...

Update: Weird... I turned off WiFi and it shortly showed me 5hours 20... turned it back on, went to 4 hours. Rebooted, went back to 2:30. turned wifi on/off now running at 3 1/2 - 4 hours according to the battery dialog... maybe one of the resets or the disk repair changed something after all...

Same here.

Battery draining really fast.

APPLE - is there a solution for this yet? I understand you guys are reaching out to customers regarding this issue - please let me know what to do - this is ridiculous.

Mid-2011 MB Air - Core i7