Battery life dropped considerably on Mountain Lion.

thanks Thinman. that sums it up for me. this thread is too long for there not to be a major problem. I give up. hang with lion or downgrade to snow leopard like it came with and enjoy my MacBooks new SSD, thanks all who posted.

after years of people complaining about this issue, seems that Apple just don't give a sh** at long as they keep getting our $$!

I reluctantly upgraded my MBA (or FORCED as I needed to install XCode) to Lion 10.8.5 from Snow Leopard. Ever since, to reiterate everthing that's been said here already, I'm lucky to get 3hrs from one charge - used to be 6 to 7 hrs! The fan is going crazy and the noise is driving me insane - hardly EVER heard the fan before the upgrade!

Used to love this machine... thanks for the Lemon APPLE! NOW, FIX THIS JUNK!!!!!!!!!!!

There is no issue. If you upgraded an MBA so old it ran SL, then the issue is the choice made. That MBA architecture should not have run well on the MBA. 2008 sample MBP am testing runs 3 hrs with ML, 25% less than the original SL it came with. Same with ios7, doe snot at all run the same way on an iphone 4 as it does on the 5 or 5s for that matter.

The Apple battery life is drmatically superior to most of the industry (certainly with the new MBAs that are up to 11 hrs of productivity). I get 6-7 hrs easily. But ML is some ways is a hog that only a more recent CPU and architecture can handle. In other words, your MBA cannot handle HTML embedded flash as mine can. And the OS architecture as well designed to use the processor only the modern one can really do. SL to ML is a jump I would have never made.

Similarly, if still using the original battery, it is perhaps time to change it? Chances are it was 20% less life if so, and I have seen how they may say 4 hrs but really give one 2.5-3. ML would have recalibrated the read and usage data of your battery.

Will upgrade to Maverick as I heard it may work very well on my MBA, but I think it the last OS I upgrade on a 2012 unit.

If ML is runs so badly on older MBAs and Apple is aware of this - then why offer ML as an upgrade path? At a minimum, Apple should have a warning of all the potential issues so that we can make the choice fully aware of the facts, without wasting peoples time having to fix a machine that was working perfectly. The hardware is not outdated - i5, 4GB ram, 256GB SSD.

If the MBA CUP architecture is not supported and the machine has a high likelyhood of not functioning optimally, simply don't offer it as an upgrade. It's no upgrade - it's a downgrade! Why wouldn't Apple be happy if we upgraded hardware to coincide with every OS version.

Except that I'm having the same issue with my mid 2012 MBA. I downgraded back to Lion 10.7.5 and that fixed the battery life issue. I've installed many more programs and it's fine. With Mountain Lion the battery was crazy bad. So your point that "There is no issue" isn't true in my case and many others.

I will upgrade to Mavericks when it comes out, as will many others who have posted on this thread. I will then post here about my experience.

In fact, I'm going to take this opportunity to encourage people to take some metrics of their system before they upgrade. That why when they compare battery life pre and post upgrade it won't be purely anecdotal. Before you upgrade, charge your mac to 100% and then time how long it takes to actually run out of battery life.

If someone has a good tool to create load, that might be good idea to run before and after. Or maybe do something as simple as play a few movies with everything else turned off and see how far you can get before you run out of power. Then do the same thing after upgrading.

Any more ideas? If so, please contribute.

To zumek,

The architecture is compatible (or no one would be able to install it), but not optimized. In other words, run Noticiation center and power sleep and your machine will eb a hog on battery. Turn these off and you gain one hour.

Aple does offer a warnign, as do the geniuses. they have those little notes/* that specify the specs and description are based on a current CPU architecture nor an old one.

Another thing is that 2 yr old apple battery has easily lost 20% life, maybe more even if telling it is 85 or 95%. ML and new SMC siply retell the values as they are and kinda kick the batteyr out the door. So if you bought a new battery for your syste, you will notice a good improvement, and once it will stabilize at 92-93% ML indicated, you will have 4-5 hours.

To -40

there is an issue. Either ML was not given a chance to settle, or your current battery is defective. Should you read the posts you will discover that Lion may say 5-6 hours but countdown in 4. ML corrects and tends to give a more accurate reading.

As mentioned above, first couple of days, as it settles, plus notification center or power nap (which I disabled), ML does drain more. but your MBA is exactly as mine so if you trully get half the life I get then you have a hardware issue at this point. Why did you not fix it under the 1 year warranty? I received 3 defective mid 2012 MBAs from the factory (trackpad, battery, defective LED screen). The battery was obvious and the geniuses diagnosed it instantly looking at the power drain. So I am not sure Lion does better for you unless you can proove that you allowed ML time to settle, did not activate every feature on it, and that, B, Lion is reporting the real countdown.

Installed ML on an older machine several times, and had the impression it drains faster. Also installed a new battery and tested each OS a week per installation. The 2008 machine performed better with ML 10.8.2-4 than the latest Lion, by about half an hour. But took me two months, the arrival of 10.8.2 that improved battery life, and a week of dedicated testing and several cycles per installation.

Agree with -40. I'm having the same issue with a mid-2012 Retina MBP. Upgraded to Mountain Lion, and promptly battery quickly degraded (health steadily declined to 0% within a few weeks). Got the battery replaced through AppleCare. New battery lasted an average of 3 hours on Mountain Lion (running basically Mail and Chrome, turned off Notification Center and Power Nap, installed Flashcontrol, and allowed the machine to run this way over several days and through a number of charge cycles--also constantly monitored the system using iStat Menus to make sure there were no runaway processes).

Went back to Lion and battery life immediately returned to an average of 7 hours (real time based on a clock, not estimated time remaining).

So here's another vote for ML negatively impacting battery life in a severe fashion on some laptops, not necessarily just a bad battery or an old machine.

Looking forward to hearing reports on people's experience with Mavericks.

"So here's another vote for ML negatively impacting battery life in a severe fashion on some laptops."

If so, then those laptops are lemons. Millions of laptops were sold by Apple last year, and this is unheard of in the genius/tech world. Yes, they heard of lemons and so on. I remmember when I thought I had a drive capacity problem, and turns out a fresh install resolved everything. By far and large, the vast majority of MBP 2012 users enjoy 5 hrs + easily.

The second lemon MBA I had was with a defective trackpad. It was shorting. From the factory. Replacing the pad fixed nothing. Long story short, how a machine is a lemon hard to tell. But if 98 MBP 2012s get 5 + hrs with ML, and 2 get three hours, then those 2 are lemons.

Years ago, when building PCs, I was very much aware that x% of units, same spec and configuration, for whatever reason, would not work. Fail benchmarks etc. Most times it was the MB. Sometimes the ROM refuses to update in some units- thus affecting performance. Sometimes it was one memory chip. I remember an entire batch of Asus p4p 800 S motherboards that were so bad from the factory that hundreds were returned. The series before or after were great but not that batch.

How can the OS be impacted? say ML refuses to update the ROM specs on the SMC, using Lion's SMC on ML, that would wreck havoc on the ML battery life calculations. Is it possible? Well, when the Sr Appple techs do the diagnostic software, they essentially get the list of all rom and firmware installed on every chip of the machine, as well as that on the hard drive.

3 hrs? I would have had Apple replace it. The geniuses hook it up and measure the drain with a multimeter. If twice the normal, three failed fixes and they issue a new MB, a new machine.

what sort of situation would cause ML to not update the ROM on the SMC for some and not others?

KaiteChase, you mentioned that going back to Lion didn't help.

When I upgraded to ML, I did exactly that. I "upgraded." When I reverted back to Lion I did a full wipe of my HD first and then I installed Lion. Lion has worked fine. Tonight I'm going to try a wipe and then install directly to ML if possible. I'm not sure if I can do that ML install as a boot over the Internet or not, but I'll try and see if a full wipe and then a truly fresh install works. Thanks for your post.

Beisarius, thanks for your replies.

First off, I made a mistake. I bought a mid 2011 MBA, not a mid 2012. So, the hardware, while still newish isn't what I said it was. I can't believe how fast time has gone by. This also explains why I didn't take it in under the first year of warranty as I didn't purchase ML until 11 months after I purchased my MBA.

I'm not so sure it's a lemon though, it may be that I had a bad install when I upgraded to ML. I'm going to retry, but do a full wipe and I will let people know how things go. I purchased AppleCare with my MBA so if the issue crops up after a fresh install, I'll take it in to Apple.

Also, you mentioned that the battery indicator is more true in ML than Lion. The issue I had wasn't so much about the indicator as the fact that doing nothing on my MBA, it would run out of power completely sometime in the fourth hour of running, meaning around 3.5 hours. Yes, I tested it. That's when I tried disabling stuff, which didn't help. This was after a few months.

So, I'm going to do a fresh install and let it sit there with nothing else installed. Currently my battery lasts about 6 hours (mid 2011 MBA 13") when used for light web browsing combined with doing nothing, with the screen on low brightness. Again, I don't go by the battery indicator for total battery life. I do real world, full battery life from 100% down to 1%. No calculations and extrapolations.

How long do you suggest I let the OS settle before I do my test?

Thanks for your help.

Maybe the ROM has become faulty somehow? I'm an OS guy, not a hardware guy. So it's all a mystery to me except that I do know that hardware goes bad and also that not all "identical" chips are created equal. I think Beisarius' ROM issue was just a suggested possibility.

-40 wrote:

Maybe the ROM has become faulty somehow? I'm an OS guy, not a hardware guy. So it's all a mystery to me except that I do know that hardware goes bad and also that not all "identical" chips are created equal. I think Beisarius' ROM issue was just a suggested possibility.

There are a lot of things it could be. And unless someone who works (or worked) at Apple chimes in, we're only left to speculate. But another data item to consider is that each release of 10.8.X has changed the battery behavior for quite a few people. No, it is NOT solved it for everyone. But the fact that 10.8.X changes affect battery life through the life of ML, suggests it is OS related and not Firmware related. Also, in my case, the recent upgrade for 10.8.5 from 10.8.4 shaved about 90 minutes off of my battery life. So, I went back to 10.8.4, and I got my 90 minutes back. Again, this suggests software. I understand the Apple is going to release a supplemental update to 10.8.5. At this point, I'm going to wait for Mavericks and see what the early reports there look like.

As a former firmware engineer, I agree with your statement; not all chips or boards are made the same. Sometimes the specs can be just close enough that under some conditions it works perfect and under other conditions it fails. So, could it be as simply as a defective battery as some have suggested. In fact, I wouldn't be surprised if it is some sort of spec/timing issues; in the end. It is certainly possible. These types of issues are generally hard to troubleshoot - because, for one, you don't know exactly what you're looking for.

Anyone have a fix yet? I still have the same issue. I purhased this for my college program requirement as well. But I'm lucky if I get 2.5-3 hours. That's with no keyboard lights and all the obvious stuff. Tried the resets etc. and just about everything. I time it with a timer outside of the computer itself. It's definitely not getting the advertised battery life. My friend has the 13'' model and it gets great battery life...so no clue why mine isn't? Genius bar has been less than helpful. I have 3 year apple care. Can I just take it back? I paid a lot for this.