Released June 2009 / 2.66, 2.8, or 3.06 GHz Core 2 Duo Processor

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Battery has high health, but gets short battery life?

I have a MacBook Pro in my house that has experienced dramatically decreasing battery life. Most of the time, I see the same behaviour with computers that have 300 - 500 + cycles, and their battery health shows up as 80% or lower. This MacBook Pro, however, has had 250 charge cycles and is at a 94% health according to coconutbattery. This means that it is at a max capacity of 6113 mAh, compared to its normal 6500 mAh. The strange thing is, leaving it on overnight it can loose 20%+ battery charge, and you can only get about 1:30 run time when idle, even though nothing is running and there is never a process running over 1-2% cpu (CPU spiked at 4% usage when I monitored it through a 100% to 0% battery discharge). I just find this odd with these stats and this performance. Given that is is a 4 year old computer, the battery specs still seem to be decent. I was wondering if anyone know of some sort of background application or something, that wont show up in Activity Monitor, that has the capability to slow down battery life. The computer has also been gradually slowing down, even though it has 8 GB of ram and 400+ GB of space free on the hard drive. I haven't tried replacing the battery yet, because this one still seems like it "should" have some life in it, it just isn't acting like that. As a note, it has never been dropped or had water damage, it has been lightly used for the past 4 years for web browsing and iWork, but never anything heavy. It has stayed indoors and has never been left in a hot car or in direct sunlight. If anyone knows something I can do to get some more battery life back, if there even is anything, I would be happy to hear what you have to say. As I typed this out, the computer battery life dropped from 82% to 63%, and only Safari was running. (it is also in integrated graphics right now, which makes it seem really weird that this is happening, could both the integrated AND dedicated be running at the same time somehow?)

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And I don't think it has something to do with the age of the mac, I have a 17" MacBook Pro from 1.5 years earlier that has had 672 load cycles on it, and it still gets batter battery life.

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Owen - I had a few like this, I ended up putting new batteries into them. Not all of the cells are in series some are in parallel in these packs. I suspect a bad cell or two is the cause here (over charged).

One of the things we all do with these laptops is leave them plugged in all of the time so the battery pack never gets the needed full discharge and lets be real here no one wants to work on a system forcing it to discharge knowing it will die in the middle of something ;-}

I bet this person used this as there desktop system, not as a traveling laptop as it was intended for.

In my case the two systems that are in the executive conference rm. used for presentations are always plugged-in inside a locked cabinet and very lightly used.

One day the CIO came by my desk telling me we needed to send these back to Apple for warranty as the batteries weren't holding a charge. After looking at the cycle history I too saw the cycle rate was way low and the discharge curve was very high (just like you). After asking some questions about these systems It hit me like a brick the battery pack was never deep cycled! I did manage to get Apple to replace the batteries under AppleCare. Now I borrow these systems for a weekend once a month giving them the needed discharge to keep them healthy.

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Yeah, I think the problem may lie with the fact that it was plugged in for days, then only used for 20-30 minutes off the charger every once and a while. The machine was plugged in at work and home for most of the time. I think I am going to look into replacing the battery with a new OEM one. Then I will see what kind of battery life it starts to get.

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Owen Cunneely will be eternally grateful.
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