Q: Battery life dropped considerably on Mountain Lion.

My Macbook Air is affected too! Turning down brightness and keyboard light pushes up battery for ca. 1h but all over i do not stay for 7h without charging. After ML update i get round about 4-5h but often less than that.

spoke to Apple support - they advised to verify disk permissions, then repair, verify disk then repair. Will now wait either 3 or 7 hours to see if it has worked.....

how do you verify disk permissions?

Hopefully Apple is investigating this issue with battery life.  I'm running a 2012 - 15" MacBook Pro, 256 Apple SSD and 8GB Apple RAM with high res (non retina) display. Battery drains really fast and I'm mostly running it on mid level brightness and just surfing the web (not even Hulu or YouTube).  Checked Activity Monitor and no runaway CPU eating processes.  Another bug I found is that when I have ramped up opening up iPhoto, iTunes, Word, and a few other applications, my MBPRO isn't releasing that RAM.  It's holding on to it so I'm having to use the purge command to free it up sometimes.   Apple, hope you're reading and look forward to the updates! 

Same problem here, on battery, less than two hours and down to 35% remaining.

Wish it was the only problem with this MBA 2011/refurbished. (Apples sez about Refurbs that they're as good as new.) This MBA 13" freezes in irregular intervals, can be several times a day, can be after a couple days ok behavior. AppleCare senior tech has walked me thru this and that (Permission repaired, disk ditto, SMC reset). No improvement. And then it eats battery, now that it runs under ML.

... oh, and, yes, firmware updated (SMC Version (system): 1.73f65).

partially replying just to watch this thread.  i'm not positive if i'm experiencing the same issue.  i've lost about 8% battery life in the last 25 minutes with ONLY google chrome, one tab open.

i left my computer (early 2011, 13" mbp with SSD and HDD (in superdrive location) unplugged, with the lid closed overnight and it lost 6% battery.

i don't recall lion using this much of my battery, but it could just be mental after reading all these horror story posts.

2011 MacBook Pro 13 inch.

I also have this issue. Dropping 2-3 hours for me. I also had issues with my network settings and had to reset them. Becoming frustrated having to move my charger around with me which is a sure sign that there is something up. Never had to do thin on Lion.

Fingers crossed here for a quick fix.

2 day old retina 2.6/16/512 unit here... after mountain lion I see about 3 hours battery timer. not cool at all.

The same with my MBA (Mid 2011,13'',128GB). I used to have power for about 7 hours, now it's about 4 hours maximum. That's too bad because I need these 7 hours for longer trips....

Early 2011 MBP and Cycle Count is 398.  They have been falsely inflated since the beginning.  We have another 5 year old white MacBook in the house that has a 244 cycle count.  It is used constantly as mine is.

I did make a Genius Bar appt because I think my battery must be bad. 

Battery Information:

  Model Information:

Manufacturer:    SMP

  Device Name:    bq20z451

  Pack Lot Code:    0

  PCB Lot Code:    0

  Firmware Version:    201

  Hardware Revision:    000a

  Cell Revision:    158

  Charge Information:

  Charge Remaining (mAh):    3892

  Fully Charged:    Yes

  Charging:    No

  Full Charge Capacity (mAh):    3892

  Health Information:

  Cycle Count:    398

  Condition:    Service Battery

  Battery Installed:    Yes

  Amperage (mA):    230

  Voltage (mV):    12340

Same here, 98% is max.

Doing nothing on the MBA, you may observe the display like a countdown, loosing 1% every 90 seconds, without doing anything.

I did all the Mac Voodoo (Reset SMC .....) nothing helps. I thought, that just the calculation is failing, because it doesn't become warmer than normal and there no processes shown in activitymonitor that could cause that.

The book shuts down when the battery is running empty, but that may be based on the calculation of battery status, too.

Model MBA, Late 2010, 11'', 2 Gb, 128 GB; Battery max 4418 mAh, battery status ok

2011 MacBook Pro 13 inch.

I also have this issue. Dropping 2-3 hours for me.

Ithamar, does your battery condition say to "Service Battery" ?

Here are the battery conditions from the Help section on Apple:

The battery condition tells you whether your battery is functioning normally and approximately how much charge it can hold.

Here are the possible conditions:

Normal: The battery is functioning normally.

Replace Soon: The battery is functioning normally but holds less charge than it did when it was new.

Replace Now: The battery is functioning normally but holds significantly less charge than it did when it was new. You can continue to use the battery until you replace it without harming your computer.

Service Battery: The battery isn’t functioning normally, and you may or may not notice a change in its behavior or the amount of charge it holds. Take your computer in for service. You can continue to use your battery before it’s checked without harming your computer.

Message was edited by: gkygrl - Macbook Pro, early 2011 2.3 GHZ Intel Core i5

I'm having same issue. Significant reduction in battery life. 2009 MacBook Pro.

Mid 2011 MBP, with Lion my battery lasted like 6 hours, and now I can hardly work for 2 hours without the charger. I'm also having trouble with the trackpad, sometimes the gestures doesn't work until I restart my MBP... Awful.