Q: Battery life dropped considerably on Mountain Lion.

I have a late 2008 MacBook Pro (2.4 C2D, 4Gb, 250 Gb 5400 rpm drive) and the impact on battery life has been remarkable. The original battery (349 cycles & 94% health) used to give me 3h 20min of life while performing general tasks (Word, Excel, Pages, email, WiFi on) and I'm now getting less than two hours. Even plugged in my battery is discharging at about 1% every 6-8 hours. I have run the battery down, left over night and recharged but to no avail.

iStat shows that the CPU runs about 5 degrees C. hotter since the upgrade. Running iChat drives the temperature up to 73 C. and fans spin up to 4500 rpm (never seen it do that before).

I like the integration with my iPad and iPhone that ML brought but the convenience that it brings is not worth having to tether my laptop to a power outlet. I'll just have to revert back to SL and use the web interface to access iCloud services.

I hope this is resolved soon; us folks with the older MacBooks can't afford to take a big battery hit and I'm not interested in replacing a perfectly good computer.

Good to hear shawow82x,  `we posted our messages around the same time.

Apple does not care about former customers on older computers. It is a sign to move on to another company. I have been an avid customer since 2005 when I bought an iBook G4 but now I am considering to moving on when Apple does not even acknowledge the battery issue....

I am not sure if this is relevant, but I took my MBA 2012 i7 out of my bag after being there for a couple of hours and waived it around and I could tell the fan was spinning (I.e. that gyroscopic kind of feeling, esp the new fan design).

Am I being paranoid.  Is the fan running when it's sleeping?  If so, that would explain battery drain whilst sleeping.

Count me in with the battery problem: early 2011 Macbook Pro 15 (17 months old, 131 battery cycles), ran perfectly fine until the ML upgrade (6-7h of battery life).
I got the "service battery" warning after the ML upgrade and I only got 3-4h of battery life. And this reduced considerably over the next days - even with 10.8.1 installed - until I reached 58% health yesterday. Even just plugging it out from the wall outlet reduced health by 2-3%!

I called Apple Support and after I reached a supervisor he took the time to walk me through the basic troubleshooting steps. Interestingly the SMC reset didn't work at all on my machine (i.e. the green light on the charger cable didn't go out for an instant as it is obviously supposed to - according to the support guy).

So we did the PRAM reset (didn't help) and after a backup I wiped the hard drive and reistalled ML fresh without any addtl programs, then update to 10.8.1.

And now: The battery behaves normally! Albeit from a lower health level: Normal consumption and runtime adjusted to the lower battery health. I get 2-3,5 hrs of runtime out of my 58% health (3200 mAh).
I then rebooted from my backup with the initial 10.8.1 upgrade install and this behaves normal too!

Now I only have to sort out with Apple who gives me back my lost 42% battery capacity, which I lost due to a regular update on a machine that's not even 1.5 yrs old...

I am so bored of this problem, that I do not even feel like following Apple's action any longer. I am really sad about the way this has been handled, to add to it, my MBP has been purchased only in Jan 2012. Unfortunately, I am in India, where there are no Genius Bars and Apple Service Stations take forever to do nothing. They are neither helpful nor work. Had I been somewhere like US or UK, then I would daily pest apple till they wld replace whatever they had to, to make my thing work. "SAD"

Tim, it's happened the same to me. I posted the screenshot few days ago and showed 6% battery health, and today it 0%! My battery is useless now, if i unplugged the charger, it's shut down immediately.

One thing which I notice that it's completely a software failure by ML is it still showing the Service Battery in my Battery Status Bar. (see the screen shot).

Apple, please wake up and do something!

I totally feel you. I too have been suffering with emmense frustration with regards to the battery life of my MBP13 after "upgrading" to ML. Aside from the fact that Im not a "techie", I live in the provincial part of the Philippines. So getting my concerns addressed is quite hard. I am greatly disappointed by upgrading to ML. I want my battery life back, but it seems like Apple isnt doing anything about it. SAD

From a standpoint of my own experience I cannot say my battery life drop is as bad as some I read here. But its enough to notice. I have gone from being close to Apple's specs on my 2011 Macbook Pro 13" to a lousy 3.5 to 4 hr life. But I also can say the temp problem with the CPU is a problem as just idle the CPU temp can raise to over 80 degrees celcius. I cannot understand with so little threads being pushed through a CPU how it can run so hot?

The update 10.8.1 has not helped in my case and the reset solutions are a crutch Apple always uses as with most manufactures of PC's to solve everything. What is even more rediculous is to have people have to do a fresh install of OS X just to try and solve a upgrade issue. Could it be that the way Apple is upgrading thorugh downloads be the issues? Ever since Apple went to a download system through App Store with Lion we have seen issues with upgrades. I have no proof this is a issue but its certainly a common denominator with this problems.

Apple has acknowledged it. A tech rep called me up and we spent about half an hour going over my system and me sending logs back to him so that they could analyze them to improve battery life. When he called he stated that he was responding to my earlier post regarding diminished battery life with the ML update.

Even after the last update, I put my MBP to sleep at 10pm and when I wake up at 6am it's already down to 93%. Every couple of weeks I let it run down to zero before recharging.

So have some faith guys, Apple is aware and they are working on it.

Well, my battery is now also rapidly loosing health. It no longer fully charges and I'm getting under 2 hours of use out of my 7 month old 15" MBP. When I first noted the extra heat and reduced life I started to wonder how much of a negative impact this would have on the battery, but now it's becoming obvious that there is a serious detrimental effect.

I have a 2010 17" i-7 Macbook Pro. A short while back I upgraded to Lion from Snow leopard. I was getting decent performance and decent battery life 5-6 hours. When I upgraded to Mountain Lion, battery life went to crap. I was watching it go down 1% per minute. So, I did a clean Install of Lion and restored my last Mountain Lion(10.7.4) back onto my machine. Battery life is 3-4 hours now. The system is sluggish and buggy. I have had crashes in Safari, which I never have had, Is there something about upgrading from Snow Leopard to Lion that makes Lion more compatible with my machine than doing a clean Install of Lion. I am thinking about going back to Snow Leopard and upgrading to Lion. Then restoring Lion(10.7.4) back.Any thoughts on this?

I'm having the same issues with a late 2010 MacBook Air. Terrible battery life, I can literally see the %age tumbling before my eyes. I've updated all the software I can, done a SMC reset all to no avail it seems. What gives Apple?

Mountain Lion is 10.8.1 and Lion is 10.7.4 but what ever you have now, it is important in the position you are in now, to have external backup, either Time Machine or a bootable clone.

I would try a Safari reset to see if that helps and if you need further assistance on re-installing, post a new thread on your particular problem, as this one is about battery problems. 

You could try using the Recovery Partition per this guide:

http://www.macworld.com/article/1161064/installing_lion_complete_guide.html

I have decided to get my own y-wing screwdrivers, a new battery replace it myself and go back to either Snow Leopard or Lion until this flaming pile is sorted by Apple. This is really really sad.  I know they don't publicly acknowledge most issues but in this case I think they should at leasat say we are aware and diligently working on a fix. Good luck to all affected, I hope this gets sorted sooner than later.