Battery life dropped considerably on Mountain Lion.

I'm still in the process of downloading my copy, so I can't speak from experience with ML, but I would start with the assumption that something is wrong with your system somewhere. Of course, there could be a problem with ML, it's too early to say one way or the other yet, but if it's a ML problem you can't do anything about it but wait, so start troubleshooting now. Try resetting the SMC. Also check all your third-party software to make sure it's compatible with ML. If any is not, update it or uninstall it.

If you've just upgraded, there is a lot going on. Give your system a little time to "settle down" first. Battery performance under Mountain Lion should be similar to what you were getting with Lion. Also... some people use real-time virus scanners. As an OS upgrade replaces a significant percentage of your files, a virus scan can also be quite intensive... especially when it happens along with indexing.

I noticed the same issue. Battery used to last all day easily on a 13" MBP with room to spare. Its now 3:30, I have used it less than normal and I am at 5% left. I hope this is not something that will be ongoing. Perphaps the OS needs to read a full cycle of the battery in order to use it properly or something. If not, this is a major dissapointment.

Being that the new Hillside Kitty is heavy on the iOS eyecandy and being a new install, lots of caches and indexes have to be built, which takes quite a toll on the battery. I suggest you use it normally for the next day or two and let things settle down, then take measure of how it behaves.

Those of who had the opportunity to see it while it was in gestation have high hopes that it will behave better than it progenitor, the despised Fat Cat (aka Lion).

I've noticed my battery life decreased after the Mountain Lion upgrade, too. Why is this? The CPU does not seem to be slammed. But, I can visably see the battery draining. In fact when I first started writing this post my battery was at 96% and now, three sentences later, without doing anything else, and without having any other applications running, my battery life is at 91%!

The fact that you're not doing anything on the Mac doesn't necessarily mean it is lazying out just scratching its ballz 😉. Open Activity Monitor (found in Utilities) and be amazed at all the automatic processes busily working to optimize the new install for your later pleasure and enjoyment.

I checked activity monitor. My system is averaging a 99% idle state. I am now at 86% battery, since my last post. 🙂

I guess we will have to see if Apple comes out with any kind of patch or it this becomes a much wider spread issue. I think Caurcoul is probably right, at least somewhat. Lets just give it a few days of normal usage and see what happens. I plugged mine if after it died and it is charging fast, for whatever that is worth. 25% charged in about 20 minutes.

You'll also want to check disk activity. An upgrade is more disk intensive than CPU intensive. Indexing is fairly mild on the processor, but requires nearly continuous disk activity until it is complete. There really is no need for concern unless things don't improve with a little time. That's not to say that you're not having an actual problem, it's just a bit early to make that determination. While ML was just released today, it has been tested for quite a few months and battery charge hasn't been a problem. When folks first upgraded from Snow Leopard to Lion, there were tons of posts then about charge times dropping drastically... which pretty much faded away shortly thereafter. There are always going to be some people who do have actual problems, but when installing a new OS, you can't really judge proper battery performance for a little while.

I just checked the disk activity and that seems fairly idle as well. I know that the upgrade requires reindexing the hard drive; Spotlight displayed a warning messages stating it needed to reindenx the drive. Is there anyway check the status of the index? 78% now.

I'm noticing the same behavior. I upgraded to ML around 11AM and left it turned on and plugged in since. I just unplugged it and in the past 30 minutes, my battery life has dropped to 77%. This is on a mid-2011 MBA with Spotlight disabled.

While reading and replying to this thread, it's dropped 2% more, to 75%.

Sigh.

Message was edited by: mevans336

And waddya know, Apple has released an SMC firmware update for the mid-2011 MBA. I just got the notification through the App Store. I bet this is going to solve my battery problems.

http://www.macobserver.com/tmo/article/apple_releases_power_nap_update_for_mid_2 011_macbook_air/

Another issue. Safari 6 consumes a lot of cpu. Perhaps this is the culprit?

Maybe. Depends on what the page it is displaying forces it to do. A simple static page with text and few images causes negligible load, whereas one laden with Flash content and the like pushes the CPU thru the roof. Not to mention the popups and extra pages or tabs that some shady sites are fond of launching.

Another thing to investigate is what the Dashboard and its retinue of widgets are up to. Some may be continuously fetching data, like stock quotes, weather info, sports results, etc., hammering the wireless connection. Others may be computing stuff, like graphing the wireless performance, drawing a starry sky, etc.

Each may not amount to much, but when they all gang up on the poor unsuspecting Mac, results can be devastating.