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I've been reading up on battery cycle counts and checked out my current count on my MacBook (13-inch, Aluminum, Late 2008) - recommended maximum cycle count is 500.

I've had this laptop now for over 4 years and at the 2 year mark I had the battery replaced by AppleCare. The first time I checked out the cycle count was today and it's currently on 1004. Now my question is, is this the cycle count of the battery since I replaced it (as in, it reads the cycle count from the battery), or is it the combined cycle count (as in, it stores the count somewhere and increments occasionally)? My assumption is that it's the count of that battery but I have no idea how to verify this.

Either way, it looks like I need a new battery ;)

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I'm pretty sure the computer is reading the battery but maybe the power manager or PRAM settings are messed up. Consider resetting both of those to see if that changes the cycle count. –  Richard Jul 18 '13 at 11:50

1 Answer 1

up vote 6 down vote accepted

The cycle count is logged on the battery itself.

I've never actually dug into the idea to see the method or technology used to store the cycle count, however I do know this to be true thanks to personally refurbishing hundreds of MacBooks. When checking over a MacBook's battery life in System Information / System Profiler I would often switch out batteries and check again, deciding if a battery replacement was worthwhile. Once the battery is switched out you will see the cycle count (along with capacity, etc) change. If you don't see it change then you either need to refresh System Profiler (command + R) or the second battery just happens to have the same info.

If you're curious you could always visit the Genius Bar at an Apple store and have them pop in one of their spare batteries that they use for testing.

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Hey thanks for the information! Do you think that 1004 cycles is about right for two years (+ about 2 months) then? I use the laptop day and night (work and home) so it does often get drained. I'm curious as to what my old battery was at but as Apple now have it I guess I'll never know! –  ing0 Jul 18 '13 at 20:31
    
I'm also debating buying a new battery for it. At the moment I get about 1-2 hours life (depending on what I'm doing) but 99% of the time I have the adapter plugged in. Given that my next MacBook purchase is going to be within about a year or so, is it really worth spending £100 on a new one? –  ing0 Jul 18 '13 at 20:33
    
@ing0 1000 cycles seems reasonable if you're a somewhat heavy user. Remember that one full cycle can be spread out over a couple of uses. For instance, if you use it until the battery goes down to 50% then charge it up, then use it again until it drains to 50% you have just then used 1 cycle. Obviously as battery capacity & run time diminishes over time you will see cycles occur quicker. If I were in your situation I would probably hold off on replacing the battery since an upgrade is a year or so away and the current battery still has some life left. –  Mr Rabbit Jul 19 '13 at 13:56
    
I think you're right. So there's no real reason to replace the battery then... I plan on passing it down to my partner when I upgrade (probably plugged in at home). Is there any risk in the future - for example could the battery eventually prevent the MacBook from working? –  ing0 Jul 19 '13 at 14:41
    
@ing0 I've seen a few odd cases where a failed battery has prevented a Mac from working properly but they are few and far between. I wouldn't worry about it. In the odd chance that that does happen though you could always replace the battery then. –  Mr Rabbit Jul 19 '13 at 15:54

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