shut down with no warning 49% battery left.

I also had that warning: replace battery, but it does not come on all the time. If the battery needed to be replaced, the condition warming would be on all the time. No?

Mac OS X v10.6: About the Battery menu bar extra for portable Macs

Nate, I can't think of any way that the situation you mention could actually affect your battery, but there is one "proximity effect" of the kind you mention that can, indeed, make it look as if your Mac has suddenly shut down.

Your computer has a "Halls effect" switch which is normally activated by the latch magnet to put the computer to sleep when you close the lid (after the delay necessary for writing the "sleep image" ). If, however, the halls effect switch (in the body of the Mac) comes into close alignment with another magnet then it will be activated, and the computer will go to sleep after writing the image. Attempts to wake it by pressing keys etc will fail completely until you move it away from the magnet, and many people think that the computer has actually "crashed", and force a restart by pressing the power button. In fact, simply moving it away from the other magnet is all that is needed for it to "wake up" again.

The usual situation where this occurs is when someone sits their MBP down on top of another MB or MBP with a magnetic latch. The magnet in the lower Mac activates the halls effect switch in the upper one. But it can, of course, occur also if another magnetic device is in close proximity and appropriately aligned with the switch.

I am wondering whether your own situation may have somehow created a situation where this could have occurred.

(see http://support.apple.com/kb/TS2917 for Apple's own explanation of the problem when "stacking" MB's and MBPs)

Cheers

Rod

So, um, think anybody from tech support reads this? Or are we all just talking to each other!!!

I'm having the exact same problem. Today I was running my laptop on AC power, no problems. Battery power was at 94% when I turned it off.

Tonight, I turn it on and it said I only have 88% battery power left (about 1 hr 50 mins), which is weird because it was at 94%. I'm online for about an hour using battery power and it just shut down without a warning message. So I switch to AC power and when I reboot it says I have 44% battery power left.

I've had this laptop for just over a year and have never had a problem until recently... the same thing happened to me last week.

I'm running the latest version of Tiger. The only software upgrade I've done is the recent iTunes software upgrade they just pushed.

Any suggestions?

my computer has been doing the exact same thing, all my software is up to date, and my battery is less than a year old. good to know I'm not the only person having troubles. this computer has had so many problems, and every time i take it into the apple store they claim its working fine and they can't seem to find any problem with it. fairly frustrating

Exact same thing happened here. I was starting to prepare my imovie project before uploading to youtube and without a warning it shut down. My batter was certainly not empty and it actually shut down just after I plugged my power cord in. The only reason I plugged it in was because I was going leave the computer alone to keep preparing, like I said, my batter was not empty. My 13 inch macbook pro is three days old 😟. What is going on??!?!?
Apple please respond.

I'm having a battery problem, with my MacBook Pro. right after i installed Snow Leopard, "service battery" alert showed up along with extremely poor battery performance. this is a new battery, my 2nd, I got it this summer. makes no sense. i hope they fix this!!

My wife and I both have MacBook Pros with Mac OS 10.5.8. We are both experiencing this random shutdown when operating "unplugged". The problem might be battery-related: when rotating batteries (and one spare) between the two MacBooks, the problem has occurred with the same battery. All three batteries are about 30 months old, and have about 50% current capacity (dixit Battery Health Monitor).

This just started happening to me, too. My System Profiler shows:
Battery Information:

Battery Installed: Yes
First low level warning: No
Full Charge Capacity (mAh): 3913
Remaining Capacity (mAh): 3913
Amperage (mA): 0
Voltage (mV): 12471
Cycle Count: 207

I don't know what the figures mean, is the battery getting ready to poop out? (That would be preferable to having some really bad problem that's making this happen.)

Same thing with my MacBook Pro. Running Snow Leopard. Battery gets to approx. 45% and bingo! Lights out, computer shuts down w/o warning. Lose all my work! Thought it was a bad battery but not if everyone else is having the same problem.

The same thing is happening to me. Again. Last year same thing happened and a new battery fixed it, but going bad again way before it should. Problem started with computer not waking from sleep, and now the sudden shutdowns. I did update Itunes fairly recently, around the start of the problem, otherwise use 10.4.11 and had not updated anything since the last time I had this problem (curious).

There are an overwhelming number of bad batteries for this machine, I would not conclude it is not the battery and I would turn in the one you just got and try another one.

Also there is another reset to try besides recalibrating, since that is not possible, (PMU?) that I cannot seem to find this time. It did not work the last time but wanted to try it anyway if anyone knows of it, I think it involves removing the battery. Please post it if you know what I am referring to.

I was lucky last time because when I took it in to Apple store it shut off right in front of them at 97% charged!

My Macbook Pro has been doing the same thing, usually when it's around 30-40% left on the battery. My system profile gives me the following:

Health Information:
Cycle count: 208
Condition: Check Battery
Battery Installed: Yes
Amperage (mA): 1042
Voltage (mV): 12529

The Battery ID is Sony-ASM*

< Edited by Host >

Same problem. This is the reading for the system profiler:

Charge Information:
Charge remaining (mAh): 5027
Fully charged: No
Charging: Yes
Full charge capacity (mAh): 5296
Health Information:
Cycle count: 423
Condition: Normal
Battery Installed: Yes
Amperage (mA): 862
Voltage (mV): 12557

I also had that warning: replace battery, but it does not come on all the time. If the battery needed to be replaced, the condition warming would be on all the time. No?

Did not work. Still shuts down without warning. However, this time the battery condition has changed to replace soon. I guess that is my next course of action. I am still wondering as, it shuts down at various stages (68%, 50% sometimes 25%) and sometimes it goes right down to the wire and provides the normal low battery warnings.

Update. As I was looking up the price for another battery I came upon this post in the review section of the MBP 17 batteries:

"After almost 2.5 years my MBP 17" Battery pulled the expanding balloon trick, eventually killing the trackpad.. I of course thought it was the trackpad until the battery expanded in the other direction.. and when the Macbook is a rockin.. well I wasn't knocking on wood.

The cool thing was after going setting up an appointment at the Emeryville Apple store, they replaced it immediately no questions asked even though my mac was wayyyy out of warranty. Cheers Apple."

I checked my battery and sure enough there was some expansion. And I did note my trackpad was not working as well as usual. Also, its been 2.5 years that I have had my MBP... I will go to the Toronto Apple Store and find out if they will be as cooperative!

I will update. In the meantime, if anyone else has the same shut down problem I recommend you check the battery to see if there is any expansion. I noted mine when the bottom of the battery was slightly jutting out of the bottom of the MBP.