Battery life dropped considerably on Mountain Lion.

Ditto. Unsubscribing. I wish everything to best of luck regardless of if you stay on ML or decide to return to SL or Lion.

richsadams, I recieved a SMC update when I upgraded to Lion (or shortly thereafter), but not one when I upgraded to ML. So, that could be a factor. However, I am already seeing improvements now that I've returned to Lion. Battery life seems better (although I haven't taken it to a stopwatch). I'm not losing battery life when the lid is closed AND the power cord is plugged in. With ML, I would drop about 0.3% every 5-6 hours. Now with Lion, I don't seem to be droping any after my first time with the lid closed for about 6 hours. So, SMC could certainly be a factor. But ML is also a factor.

I have given up on my MBP running 10.8.2. I've done multiple clean installs, reset SMC, recalibrated the battery and continue to get a mere 2 hours on battery use for web use only. Heaven forbid that I actually need to edit images or work while on location.

Is this actually causing peoples battery to drain from 100% to 0% whilst asleep like mine is doing at the moment?

I have tried reset the SMC and PRAM but i dont think it has made a difference to be honest, i re-calibrated the battery last week which solved my problem until yesterday when it decided to start doing this again......

Is it a battery problem or am i encountering the ML bug that seems to becoming an epidemic?

I have a late 2008 MBP 15", 512gb ssd, 8gb ram running ML

Cheers

Darren

So, I wanted to share my experience here with OS X ML and my Late 2008 MBP:

I did noticed as well the dramatic battery performance drop, to basically half of what it used to be. I can see the battery pretty much draining by just reading a page, with an estimate of 1:40 of running time. So I decided to do a clean install, with nothing added. Same issue! CPU use was near zero, laptop was hotter than usual. I then used Coconut battery, to monitor the power load from the battery. It reported a load of about 19 to 21 watts, idling, and that's while using the best power saving features like brightness to near zero, and GPU set to the 9400, and Bluetooth off.

Then I did a clean install of Lion, straight 10.7, no updates. Amazingly, battery load went from 20 watts to only 11 watts with half brightness on the screen. Almost half the load! The estimated running time went up to 4:54, with a battery capacity of 90% which is absolutely acceptable, considering this is an old battery and memory was upgraded on this machine. Did the combo update to 10.7.5, and the load is still the same. Laptop is cool to the touch and still as fast, with battery on the almost 5 hour range.

Based on what I saw and was able to measure, I believe this has something to do with the Intel SpeedStep management and certain processors. It wouldn't be the first time that an operating system has difficulties handling a power management feature, and to be honest, I am sure Apple will have a fix for it on the next release.

Now, keep in mind that this is just my opinion. I hope this helps any of you. I'll keep monitoring this thread and keep posting as I do more tests.

Do you ever have the problem of yours draining battery whilst sleeping at all?

Cheers

I sure did! It would drop 20% on standby within an hour. That's something I will be testing with Lion tonight, I'll keep you posted.

Its really annoying me now, tried alsorts to cure it and a battery recalibration seemed to fix it for approximately a week and then it started playing up again....i take it a new battery wouldnt fix this then?

My battery has 492 cycles so its getting on now but seems ok running on the battery so doesnt indicate its shot at.

The issue is Mountain Lion, just revert to Lion or Snow Leopard for now. Nothing you do with the battery, SMC, apps, NOTHING will cure it until Apple fixes the issue on the OS. So, rollback, relax and wait until is fixed.

Excellent, cheers for the advice. hopefully they will rush it through.

Next mission....rollback haha more research 😁

I experimented with an even older machine, an early 2008 MBP. I did perhaps 6-7 installs, each a few days to a week max. In the end, these are my observations:

- SNOW LEOPARD gave approx 3 hrs on that 5400 mah (new) battery

- LION 10.7.4 gave 2.5 tops

- ML 10.8.1 1.5 hrs

- ML, 10.8.2, 3 to 3.5 hrs

All at 50% brightness. Conclusion: ML can perform as well or better on older hardware than Lion. But 10.8.2 clearly outperforms 10.7.4, and I redid it three times to be sure.

Now, my 2012 4th MBA replacement, that clearly had a bad battery problem from the factory, is also running very well, 6-7 hrs. The one thing I do not have any longer is FLASH.

Sleep tests on the 2012 MBA. Overnight it drops 5% in sleep. Bad, right? Means 10 days tops standby. I then observed that daytime its sleep is consistently 1-2% per 10 hrs block, or 30 dyas standby.

Then I left it 24 hrs and even 48 hrs. The drain while in standby flattened, with 7-10 percent over 48 hrs. That gets very close to 30 days standby. So essentially:

ML does not behave at night the same way as daytime. I have NO IDEA why

long term sleep mode does flatten out the discharge

New battery works, hence the previous battery was defective on arrival.

Key to these xperiments no Video left on or installer program. Anything that might throw off the dGPU has to be off.

No doubt for some people will vary. But I strongly encourage to go back on the forum, and use the simple solutions first. :

- One install

- One battery replacement

- Warranty for MOBO replacement OR

- Drop OS.

Anything beyond that gets very time consuming. I was able to fiddle with this due to having multiple units so my productivity was not affected.

Apple, the battery life is still poor on my 13" MBP, screen brightness @40%, ML 10.8.2. Still waiting on a fix to improve battery life, please roll out an update soon as I'm only getting 3.0 hrs on a typical charge where I would get almost 6 hrs under OS 10.7.

I'm aching for an update. Battery life is awful for me on MacBook Air 11" since ML.

Did an SMC reset, etc to start with, then bit the bullet and did an absolute fresh install of ML (rather than from Time Machine) and it's still no better.

Does an 11% battery drain (from 100% when I closed the lid last night at midnight to now firing it back up at 5pm) seems reasonable or not?

Either way, in use the battery life isn't as it was prior to ML upgrade.

...and there goes another 10% in 20 mins and that's 30% brightness and I have firefox open typing an email. (as opposed to heavy web browsing with Flash objects)

I do see Firefox Plugin Process (Shockwave Flash) as a background process gobbling 4% constant CPU though. I might disable to see if that's having a play in matters - though it'll probably have an effect on sites I visit.

Its totally not reasonable, and an indication of problems in ML. My system was asleep from 12:42pm at 97% while unplugged, and woke up at 7:58pm at 90%. Seems like an unreasonable drop for about 7 hours... while ASLEEP.

hey guys - you know mountain lion has a power nap feature that does certain things when your computer is asleep. It may be that you have this activated and it drawing on your power. Try turning it off and seeing what happens.