Why does my laptop suddenly shut down when battery drains instead of going to sleep??


Mac Convert for Life
I have a MacBook Air (late 2011 model). When I continue to use it until the battery drains (to calibrate it), it used to just sleep when the battery drained, but lately it's been shutting down completely. Why? Should I be concerned?

BTW, iStat says battery health is at 87%, so I wouldn't think that would cause said issue.


How many charge cycles do you have?
You should reasonably expect that it's time to replace your battery if you have more than 1,000 charge cycles.
As it's only about 1 and 1/2 years old - 1,000 full charge cycles is a lot of charging. I have used an estimate of about 100 charge cycles per year for normal use - but some folks do have a need to charge considerably more than that.

I would say that 87% battery health approaches the time for replacement, assuming that you also have a lot of charge cycles.
When I see a battery at 85%, or less - the battery life seems to go downhill fairly quickly.

So - lots of cycles, and decreasing battery health - should mean close to end-of-life for that battery.


Mac Convert for Life
Hi, Delta. I only have 752 charge cycles. And I don't think it's an issue of battery life/health because I still get easily 4 hours of battery juice on a full charge.


Just my opinion then, the "calibration", although useful for some situations, may be counterproductive for you (I'm guessing that you try to follow Apple's suggestions. IMHO, they recommend that be run too often - but what do I know?)
I calibrate once, twice at the most per year.

752 full charge cycles is a LARGE number of full discharge/recharge cycles in 1.5 years....
figure it out, it's the equivalent of COMPLETELY discharging and recharging to capacity every 18 hours since you purchased it.

Contrast that to my MacBook, which I may only use on battery once a week or so, generally it's plugged in. After 2 years, 8 months, I have 73 (!) cycles, so I have accumulated about 2 full charge cycles per month.
I'm not saying that you need to work like I do (I hope not!), but that battery usage is a very individual thing... You have a very high use on battery, so as a result, you get to expect a relatively short calendar life of your battery before it can be considered exhausted.
So, it's just something that you get to watch for.


Mac Convert for Life
I was under the impression that calibrating would prolong battery life, not lessen it. I was also under the impression that keeping your laptop plugged in was not good for the battery life either. Are these things not true? I'm very confused now.


I didn't say anything about calibration AND battery life - I was only expressing an opinion that, because you asked, you seem to be concerned about an unexpected aspect of the calibration process, which you could avoid that concern by not calibrating your batt so freaking often. :D

Or, not calibrate at all (read on...)
Check this article - http://support.apple.com/kb/HT3557
Scroll down to the calibration section (Read the rest if you like), and check the last sentence in that calibration paragraph.

and, lots of good links to other info at the end of that article, that should help alleviate your concerns (and perhaps educate you a bit, too :D )

I think what you should take away from this - is that Lithium Ion batteries do not take kindly to complete discharges - that's completely flat where your laptop shuts off. You posted here with the question about full discharge bringing on a sudden shut off. I would suggest THAT is not good for your particular battery, and you should avoid letting your laptop shut off due to a depleted battery.
THAT is my concern about calibration, and particularly for doing it "too" often (because it fully depletes the battery)
If THAT concerns you, then have your battery replaced.
However, if you still wish to continue to use your battery, because the battery life continues to be satisfactory for your, then, continue to use your battery, until the performance (and the user time from a full charge) is not satisfactory.

So, your ideas about battery life are correct (more or less)
Calibrating maximizes the use of your battery, by optimizing the time that you get from each charge.
The idea that calibration makes the battery last longer before it is eternally exhausted (and won't hold a charge anymore) is not quite true.
I don't leave my MacBook plugged in all the time, but it only is used on battery for more than a few minutes a couple of times a month, when I let it run down to 25% or so, then charge back up. That's just how I use it, and the battery gets full exercise every couple of weeks.
Is my method the "right" method to follow? Works for me. I don't need to be portable, but it gives me the choice. If you like more portability, then that's what YOU do.

I've read lots of posts on similar forums where users want that perfect plan to make the battery last "forever"
Guess what? It isn't going to happen.
Just keep in mind that that any rechargeable battery has a limited life. All batteries will wear out. And, if you keep the computer, you will replace the battery at some point.
Follow the tips to help you work better and longer while on batteries.


Mac Convert for Life
Delta, thank you so much. I must have missed that one line at the bottom when I read the manual. lol I never knew that about MacBook Airs. I will no longer be calibrating (draining) my battery so often. Thanks again, you are a wealth of knowledge!

Edit: Still reading those links at the bottom of that link you gave me. omg, I never knew about the "Option + click" for the battery condition!!!
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