Q: Battery life dropped considerably on Mountain Lion.

To tell whether PowerNap is working, put your machine to sleep overnight; then, run console.  If the machine has entries every hour, it's working...

Remember that it ONLY works on mid-2011 and 2012 Air's and the rMBP (retina MBP) with Mountain Lion, IF and ONLY IF you've installed the most recent SMC.

Also, has anyone considered that this may be a problem with Chrome and/or Flash being enabled?  I have friends with identical machines who get half the battery life I get.  The only thing I can think of is I only use Safari and I never installed Flash or Java, or any hacks for that matter...

That's a possibility. After I installed ML, I left my MBP plugged in and running overnight, with Caffeine to prevent it from sleeping, so it could do the full Time Machine backup right away. A lot of changed data to backup after the update.

Maybe that's why I haven't had the battery problems?

But the thing is... I'm using Time Machine and have no decrease in battery life. I don't know why. It doesn't seem as if the problem is model-specific and I'm running most, if not all, of the processes that others are flagging as potential culprits. I'm sure that it must be an OS bug but I can't pin it down on my machine.

Apple obviously knows that there is a bug somewhere, but is having difficulty finding the common thread that links the problem. I hope for the sake of you that are having problems that it's a simple OS patch.

I have a Time Machine backup with my oldest full backup of March 20th. I've only used Lion and Mountain Lion on this particular backup and have had no problems, so I don't think that the problem is TM.

Clinton

Chrome does force you to the discrete graphics card, whereas Safari doesn't, so someone running Chrome will definitely have worse battery life than someone running Safari.

However, I think the people having problems here are seeing half the battery life after the Mountain Lion update when keeping the exact same usage patterns they used before, regardless of what apps they use.

Hi all,

Oops, downgrading to Lion did NOT solve the enire battery problem!

I restored my startup drive from a time machine mackup made just before the ML upgrade, after having had serious battery life issues as I reported 2 days ago in this thread.

Battery life first went back to normal, capacity in coconut also showed 85% again which is probably what it was before the upgrade to ML (after ML it sometimes showed 30% and a message to replace the battery showed in the menu bar).

However, I purposly did not connect the macbook to the AC power last night (at roughly 50% charge) to see if it would come back from normal sleep in the morning. Unfortunately it didnt: It had gone in hibernation with apparantly 0% charge left, which is not normal (there should be like 40% left). When reconnecting to AC also the replace battery now service message was back !!

I just did an SMC and PRAM reset,and hope that will finally get me completey back to the pre-ML situation.

But first signal is not good: after SMC and PRAM rest my MB is still reporting "Replace battery now" and I would have expected that if that would not reflect the true battery condition, this messsage would have disappeared with the SMC reset.

So it's looking more and more like Apple (through ML) caused irreversible damage to my macbook (1100 euro 3 years ago). Although I'll probably never be able to prove it.

Werner

Just to chime in... I just got a brand new MacBook Pro 15" and did nothing but install mountain lion... And see! Barely more than 2 hours, even with the screen darkened down, wifi turned off, ...

I have the same issue, kept me posts it also please?

I tried downloading this http://support.apple.com/kb/DL1559, but it says it cannot work with my system. 

'This software is not supported on your system'

Any ideas?    

So you have a Retina display and you can't use the updater? It says that it works on 10.7.4 and 10.8...

Clinton

I find it hard to beleive a bug like this could have went undetected with months of beta testing prior to release.

Chiming in: Early-2011 15" Macbook Pro. Used to get 7+ hours battery before Mountain Lion, now I get 4 if I'm lucky.

If I was into conspirecy theories, I'd think Apple removed the Time Remaining display from the menu battery so we woudln't see it...

That is an interesting suspicion! My MBA 13" (2011) does freeze in irregular intervals. Whenever it does so, there's at least mail.app running and occasionally mail.app shows weired graphics debris from another application running 'in behind it', e.g. Safari. To be sure, it froze under Lion too, battery life seemed 'normal', fans ran less often or not as speedily. So, it maybe that my MBA has faulty memory (as tech. supporter seemed to think) and of course the battery thing may have entered when upgrading to ML.

With all the friendly help from AppleCare supporters (last one senior tech in Ireland) best we managed was to get rid of the MBA refusing to wake from sleep (set sleep times below 15 min. for screen and computer). The freezes still happen and I can't make out any rhyme or reason other than Mail and Safari running (along with other like DEVONthink or Preview).

Chiming in for data capture

Apple MacBook Pro 2.7GHz Intel Core i7 (13-inch DDR3) Early-2011

Upgraded to Mountain Lion and battery down from 5-7 hours to 3 max

Also changed from 5400 drive to SSD and battery life still down to 3 hours which for SSD is mad

I had the same probem when going from Snow Leopard to Lion and for a few months it was MDS/MDWORKER until apple fixed something and battery went back up to 5-7 hours.

Clearly something is broken again in Mountain Lion

Beginning to wonder if staying 2 releases behind is wise now until the OS is settled as this is becomming a common problem everytime I upgrade and Id rather have the battery vs the new features

I can add my experience as well. New Reitna MBPro, came with Lion, updated to Mtn Lion. The first time I really tested battery life was yesterday on a flight; in less than two hours, I went from 90% to 23%. Took machine in to Apple Store today, but they had no idea about it. Just in the time we talked about the batter life, it went from 90% to 81%. Definitely, something's wrong with battery life in Mountain Lion.

After reading most of the pages in this thread I decided to do a battery test on my new MacBook Pro with the following spec:

Model Name:          MacBook Pro

  Model Identifier:          MacBookPro9,1

  Processor Name:          Intel Core i7

  Processor Speed:          2.6 GHz

  Number of Processors:          1

  Total Number of Cores:          4

  L2 Cache (per Core):          256 KB

  L3 Cache:          6 MB

  Memory:          8 GB

  Boot ROM Version:          MBP91.00D3.B06

  SMC Version (system):          2.1f170

  Serial Number (system): ?

  Hardware UUID:          509A5335-8B17-5FC9-86F3-A999092DDEB2

  Sudden Motion Sensor:

  State:          Enabled

It has now been running on battery for 1 3/4 hours (105 minutes) and showing:

This macbook had a clean install done with ML and the battery was full (100%) when starting the test.

I have nothing much running except Safari.

Will report back to see how it goes.