Mac crashing on battery power
December 4, 2010 5:33 AM   Subscribe

I fell asleep a few nights in a row with my Macbook running on battery. I never did this before and now the laptop crashes erratically whenever running on battery, even when mostly at full charge. I assume the events are related, and that this may be analogous to driving your car until it runs out of gas: bad for the car. Advice? Did I ruin my battery? Is there a fix I'm overlooking?
posted by dgaicun to Computers & Internet (9 answers total) 1 user marked this as a favorite
 
No. In fact, in some cases it's good to run your battery down. The Mac won't let your battery's charge get so low that it causes damage. Your car analogy is incorrect. Here's the first link I found talking about battery health.
posted by Geckwoistmeinauto at 5:38 AM on December 4, 2010 [1 favorite]


The mac guy in my office usually suggests people run AppleJack to try to fix minor issues. Maybe it's worth giving it a try.
posted by Geckwoistmeinauto at 5:39 AM on December 4, 2010


I don't think the events are related. Doesn't mean they aren't, of course.

I suggest:

Take an 8 hour block of time and run the Mac on wall power. Note crashes or none.

Run the Mac on battery. Note crashes.

Ideally, you need to either be able to consistently identify these problems with the battery or make the assessment that the power source is immaterial. In the case of the former, borrowing a battery from someone with a similar Mac is the fastest way to see if the problem is the battery, ONCE YOU HAVE ESTABLISHED THAT IT ONLY APPEARS WHILE BATTERY POWERED.

If the problem goes away with a borrowed battery, it's highly LIKELY, but not definite, that you can solve your problem with a replacement battery. If the problem does not go away, then the remaining issues are the remaining hardware in the Mac or the software.

The key to troubleshooting is to get a repeatable problem, change one thing at a time, and take accurate and thorough notes on what you did and what the result was.
posted by FauxScot at 5:57 AM on December 4, 2010 [1 favorite]




Laptops get a lot hotter while the battery is discharging. There are many ways crashes can be heat-related. I wouldn't go changing things in software until I checked that the fan is working well and the vents are clear of fuzzy stuff.
posted by fritley at 6:20 AM on December 4, 2010


Hold down the option key and click on the battery icon in your status bar and make sure it says "Condition Normal."
posted by andoatnp at 7:57 AM on December 4, 2010 [2 favorites]


Agreeing that running down the battery doesn't seem likely to be the problem - as Geckwoistmeinauto says, that's actually recommended to do sometimes to keep the battery power meter accurate.

Overheating is a good thing to look at - there are various utilities and widgets you can download that'll tell you your computer temperature and whether your fans are running. I've been using one called FanControl on my Mac since I had a few overheating scares. You can also reduce the odds of overheating by running your computer on a flat, cool surface or slightly elevated (say, with a book holding it up on either side but empty space in the middle) and see if it still crashes. When you talk about falling asleep using it, it makes me think you probably had it somewhere soft - on top of a blanket or on your bed - which would insulate it and keep it hotter.
posted by Lady Li at 8:39 AM on December 4, 2010


Response by poster: Yes the laptop was on my bed, LL. It could have overheated, would that destroy the battery?

What I'm seeing right now is: the battery charges normally, and my computer isn't giving me any alerts about the battery.

But I can't turn my computer on on battery power; the screen lights up briefly, but the computer turns off immediately.

If I turn it on, and then run it on battery, the computer shuts down when the battery reads 70-90%.

On the cord there are no shut downs. It's definitely a battery thing.
posted by dgaicun at 5:57 AM on December 5, 2010


It's too late/I'm too lazy to post the links I can't remember off the top of my head, but search for how to do the following things on Apple's support site (support.apple.com)

1. Reset your SMC
2. Calibrate your battery (apple.com/batteries)
3. If neither of those work, bring it to an Apple Authorized Service Provider.
posted by sleeping bear at 12:34 AM on December 6, 2010


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