OS X 10.5.8 update: MBP shutting down

[Blue Velvet]

Since I finally got round to updating from OS 10.5.6 to 10.5.8 the other day, I've had problems with my MBP (17" 2.33) randomly and occasionally shutting down. Never any problems with 10.5.6 but had to upgrade to get Safari 4 and iTunes updated.

A couple of times, it seemed like it was just turning off with the battery run down without giving a warning, but just a few minutes ago, still running off battery, it just suddenly turned off while I was composing an email, needing a restart.

Not doing anything strenuous with it, but was curious if I could figure out what the story was with the help of lovely forum members. If it's something I'm doing, then I'll stop. If it's something else, then it might be something to look into.

Thanks in advance.

 

[BlueRevolution]

Is it shutting down at any particular time of day? Does it just power off like you held down the power button, or does it take a few seconds to turn everything off like you went to  -> Shut Down?

 

[Blue Velvet]

Is it shutting down at any particular time of day? Does it just power off like you held down the power button, or does it take a few seconds to turn everything off like you went to  -> Shut Down?

Thanks and nope, it's not on schedule, and it's not a gradual process. Screen goes suddenly black and the machine is off. This is usually somewhere around the 30% battery charge mark as shown on the menu bar.

However, I looked at CoconutBattery for the first time in a while this morning, and it's now telling a completely different story than when I last looked at it about a month ago.

Battery Loadcycles: 41
Age of Mac: 32 months
Current capacity: 2995 mAh (47%)​

Last time I looked at it less than six weeks ago, it was saying about 65% health.

I rarely use the machine by battery, and haven't been great about looking after it, but sometimes it's handy to move the machine around the flat. So, it seems that the battery is dying, but instead of warning me that power is running out, it just shuts down. I guess three points lead on from this:

1. Is there any way to fix the problem with it not warning me that it's about to shut down? I would recalibrate the battery, but it's not even getting to the stage where it warns me, just cuts out instead.

2. What's the minimum battery health I can still have, but still run the machine at full speed from the mains charger? I'd rather not buy a new battery right now, times are a bit tight.

3. Out of curiosity, what would have happened to change all the battery readings and the way it subsequently behaves in updating the OS?

 

[BlueRevolution]

Talk to Apple. They should replace it under warranty (they did when my MacBook Pro experienced exactly the same problem), and if your warranty is expired, it's still worth a shot. I've heard of them replacing obvious manufacturer's defects out of warranty.

Battery Loadcycles: 41
Age of Mac: 32 months
Current capacity: 2995 mAh (47%)

Unstable battery aside, you shouldn't be at 47% after only 41 cycles. My iBook's battery still has 76% with 77 cycles under its belt.

2. What's the minimum battery health I can still have, but still run the machine at full speed from the mains charger? I'd rather not buy a new battery right now, times are a bit tight.

You can run the computer perfectly well with no battery at all.

 

[Blue Velvet]

You can run the computer perfectly well with no battery at all.

Not so, according to Apple.

It seems highly probable that by running the MBP for almost three years from the mains with only the occasional charge, that it's damaged the battery to some degree, so I'm left wondering at what point the battery becomes useless.

 

[BlueRevolution]

Interesting. I did not know that. Given what the support article says, I don't imagine it needs more than 10% health, so long as the battery can still provide a bit of juice now and then.