Battery life dropped considerably on Mountain Lion.

The only way that Apple knew I had the problem was from this forum.

TEST REQUEST...

There are several tests we can conduct to help us understand if this is a power consumption problem or a battery charging problem. So, if you can conduct the following test and post your results, that would be very helpful.

Needed:

Your MBP or MBA running ML. Once someone performs the test, I can conduct the same test on my MBP on Lion. You will need to run the System Information app. You can get to this in your Utilities folder, by searching for it, or navigating to it by: [Apple Symbol in the Menu Bar] -> About This Mac -> More Info... -> System Report -> Power (on the left hand side). Then look at the Battery Information on the right hand side. You will also need to hit File -> Refreash Information in 10 minute intervals. If you could do it for an hour, that would be better, but doing it over a 30 minute period really is the minimum amount of data we can use.

Test:

Within System Information, capture the following information: Charge Remaining (mAh), Fully Charged Capacity (mAh), Amperage (mA), and Voltage (mV). Using your battery indicator, also make note of the % remaining and Time remaning. Capture this at the start of your test, repeat the test 3 times - once every 10 minutes (or every 10 minutes for 30, 40, 50, or 60 minutes; depending on how much time you have to help out). Try not to do anything that taxes your machine during the test.

Please post your results here.

Shall try your suggestions when I return home.

Many thanks

Airuser

Additional Testing inquiry:

Apologies if this has been tried.

A google search for Apple discussions did not turn it up.

For those wth poor battery life, can you boot into the recovery partition (hold down command+R keys) and once it boots, select Use Safari to Read Technical Articles. (Safari actually searches any ol' place you want)

Web surf and monitor your battery use.

My Macbook Air with ML is pulling better than 5 hours, but then I didn't have issues with it.

I am monitoring this issue for a user at my work site.

Does Recovery Partition work with notably better battery performance or is it the same? This is the equivalent of the CD-boot troubleshooting that Apple wanted done to guarantee that software isn't the problem in times past.

I've conducted the test on my 2011 MBP running Lion, with the results posted above. With an average current drain of -790mA, I would expect the remaining capacity after 1 hour to be 4761mAh. At the end of Test 6, the actual capacity was 4816mAh, which is better than was expected. The variability in the Time Remaining is simply reflective of my doing things periodically, such as flipping to the browser versus flipping to Excel. When Chrome has focus, my current would jump to around -1200mA. For this test, I did not spend a lot of time with Chrome having desktop focus.

I would expect ML to behave similarly if there is NO charging problem. However, if the Expected Remaining capacity is significantly higher than the Actually Capacity at the end of Test 6, then a charging problem cannot be ruled out. So, once we get some ML test results we can see if this idea pans out or not. Depending on what others find, we can try a similar test to see what happens when the battery is charging.

Happy New Year 2013!

Any ML MBP/MBA users with this battery issue wiling to test your machine for 30 minutes and post your results?

Hi, i'm willing to test as i have this issue as well. I have MBP late 2011 with ML. Please write me how to test.

Thanks.

Thanks bApTizE. Just follow the steps listed here: https://discussions.apple.com/thread/4135250?answerId=20748047022#20748047022

obviously i need to have the battery fully charged before doing the test, yes??

also, do i leave the computer idle? can i surf the internet?

All i had running was safari with two tabs and the system information window. Test 9, i had a phone call and the display went off after 2 minutes. Please let me know if this is good or should i get better results with Lion?

Thanks.

My battery life in my Mac air this descended quite quickly after I upgraded to mountain lion. I have upgraded with every update that is come my way but nothing has been effective to improve the battery life. Right now it works out to be about a five hour work time after age full charge. I really regret not staying with Lion. That was a great operating system for my computer. My OSX 10.8.2 This is my configuration:

Model Name: MacBook Air

Model Identifier: MacBookAir3,2

Processor Name: Intel Core 2 Duo

Processor Speed: 2.13 GHz

bApTizE, Thank you for posting your results! It is exactly what I needed.

Your results suggest that a battery charging issue could be the problem and cannot be ruled out; as could it be a problem associated with the accuracy of how the battery readings are reported (but I doubt it is the latter). But here's what I'm finding based on your obserations with ML.

1. Your battery life is approx. 60% of what it should be based on the initial capacity of 5516 mAh and an average current draw of 707 mA. I would expect your battery to last almost 8 hours (which is what is reported from the Time Remaining field) since 5516 mAh / 707 mA = 7.8 hours. But, you'll noticed that after 1 hour, your battery has dropped to 75%, meaning you are only getting around 4 hours the way you were using you computer during the test.
2. Your current drop is greater than expected (707 mA expected versus 1408 mA observed). After 1 hour, with an average curent of 707 mA, I would exptect your remaining current to be 5516 - 707 = 4809 mAh. But, your results indicate 4113 mAh. This isn't close and would reflects an average current of 5516 - 4113 = 1408 mAh. This is about twice the drain that is reported (707mA) and is greater than your largest current draw (1089 mA)! This means that either 1) the software is reporting an incorrectly low current drain or 2) the battery was not charged to its full capacity due to over/under charging. I suspect the latter.

What this means is that we can't rule out a battery charging issue as the root cause of what's going on. Similarly, we can't completely rule out some other bug that is incorrectly reporting the actual current draws. I'll need to think about how to troubleshoot this more, but it means that the problem IS NOT necessarily the current drain based on what you're dong on the computer since that appears to be 707 mA, which seems reasonable.

These findings also suggest that the problem is software (or possibly, but not as likely - since it works with Lion, firmware) or configuration / cache related, and not battery related. In other words, a battery replacement isn't likely to fix the problem - unless the battery was previously damaged due to under/over charging or heat.

I lean toward configuration, cache, or software rather than firmware because my MBP worked with Lion but misbehaved under ML. It it were solely a firmware issue, I would expect it to continue to misbehave with Lion. For the same reason, I don't think the firmware is reporting incorrect current readings.

Good data and thanks again for testing. Now to give it a bit more thought as to why. But I'll definitely share these findings with Apple via their feedback URL since I think they should really look at their charging algorithm to solve this one.

Hi,

Thanks for the explanation! do you work in apple? Please keep us updated. The mean reason i switched from PC to MACBook was battery!! I will give it a month or two before i switch back to lion.

Hi bApTizE, No, I'm not an Apple employee, but I was previously a firmware / software engineer. Keep an eye out on your Full capacity on your battery. If it drops below 5400 mAh in the next month or two, I would recommend you drop back to Lion since that would be a 100 mAh drop in a very short period of time.