Q: Battery life dropped considerably on Mountain Lion.

I'm seeing a best-case drain of about 20% per hour also.

Apple contacted me and I worked with them to send a bunch of info from my mid-2011 MBA/4G/256G.

They of course didn't promise a fix, but they reached out to me, so I'm satisfied so far.

My computer (Early 2011 17'') Now consumes more power than it gets from a charger. Additionally it loses a percent of power every 30 seconds or so... So ya... Fun! LOL

When playing games or even sitting idle with no apps open my computer loses its charged while "charging".

The computer only charges while asleep or turned off.

im having the same problem. even plugged in it always says 98% even when the light on the charger is green

My battery is also draining very fast on my early 2011 13" MBP, since i upgraded from Lion to Mountain Lion.   With no current open applications or programs besides Safari.

Well after I got all worried about this, I decided to run my MBP on battery for a while to see what would happen.

It was a little disturbing to see it drop 3% in the first minute and a half after startup, but after that the battery behaved more sensibly. I went from 85% to 80% in about 25 minutes while doing not much of anything except opening and closing apps, turning the camera on (opening photobooth), etc..

So I shut down at 80%, waited a couple of minutes, and plugged in my power adapter, and the light turned orange after a few seconds, as usual. It looks like it's charging just like it always has.

I really hope there is nothing bad about Mountain Lion that can't be fixed, because I really like the OS. I hated Lion, but this release really surprised me. I wasn't expecting it to be slick at all, but it really is.

Just to chime in, I'm running an early '11 MBP (specs below).

Overall battery life in Mountain Lion has been consistant with Lion and Snow Leopard, no changes.

As an anecdote, in Lion, however, I did notice a significant battery life drop that seemed to be related to using Google Chrome. I stopped using Chrome, switched back to Safari, and battery life has been fine ever since. Upon further investigation, it appeared that Chrome preferred to use the discrete/dedicated Radeon GPU in my MBP as opposed to the integrated Intel HD. This made a huge difference in battery life for me. I do not know if Chrome has since been updated to address this I stopped using Chrome approximately six months ago and battery life has been fine.  I also run Firefox (FFX) as a backup browser for specialized websites (namely academic stuff) and it does not replicate this behavior as was seen in Chrome. Safari 6 has been running fine and battery life has held steady at around 5-6 hours of namely web browsing, e-mail, writing/typing, music, etc.

Also, I installed the "Click2Flash" Safari extension to turn off external flash sites by default

Does this issue affect the new MacBook Air's that are shipping now?   I'm thinking of ordering one, but perhaps I should wait a few weeks.

It's definitely a software problem, when it's solved, there will be a patch, and your new Book will be fine.

Check the Macbook Air Forum for similar threads, Calbear88...

I found that the Send To kindle application was causing the battery drain on my system due to a constantly running bash script that used about 10% of 2 CPU cores.

I had to delete the app manually to remove the bash script and prevent it from running. Maybe an update is available.

On the contrary - I;ve found with my mid-2011 MBP that the battery life has been extended - lasts at least twice as long as before - especially when on standby (lid closed) - left it for 12 hours lid closed and it drained less then 10% - that wasnt the case before...am very impressed

Since upgrading to Mountain Lion my mid-2011 MBA's battery life is shortend to nearly 60% of battery life time of OS X Lion, and fans are running very loud most of the time...

The much higher CPU usage of mountain lion applies to my iMac as well. While with lion the fan was hearable very seldom, now with moutain lion it's running permanently a high speed. I'm looking for a path to downgrade to lion.

Also having major battery issues after installing Mountain Lion. Not making any changes myself though. I see Chrome may be a cause... I have that installed. Hmm.

Also having major battery issues after installing Mountain Lion. I'm not making any changes or doing any tweaks to sort it out though - Apple will have a fix for it soon. I see Chrome may be an issue, which I have installed. Hmm.