How is this even possible? (battery health)

Discussion in 'MacBook Pro' started by markyr17, Nov 17, 2013.

  1. markyr17 macrumors 65816

    markyr17

    Joined:
    Apr 8, 2010
    #1
    The original max mAh for my late 2013 rMBP is 8440
    The current max mAh is 8624

    Is this just the battery monitor program going wonky? It's worth noting that the 8624 is also what I see when I look in system profiler. Where is the 8440 original max number coming from?

    Thanks
     

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  2. teotuf macrumors member

    Joined:
    Jan 24, 2012
    #2
    8440 is the design capacity.

    These batteries sometimes ship holding charges better than the design capacity. It's not a software mistake, as in windows 8.1 it reports the same charge capacity.

    For example, on my rMBP13 late 2013, design capacity is 6330mAh, whereas my current max capacity is 6682mAh. And it fluctuates regularly.

    At the end of the day, the extra charge is going to give you maybe 15 min of extra battery run time. Just stop worrying about it.
     
  3. markyr17 thread starter macrumors 65816

    markyr17

    Joined:
    Apr 8, 2010
    #3
    Thanks.

    I was more wondering if it was an error or not, but as you say, the batteries can hold a charge higher than capacity.

    I'm not worried about it, more actually happy to know that i will still be at 100% capacity for a bit longer
     
  4. Dovahkiing macrumors regular

    Joined:
    Nov 1, 2013
    #4
    I'm not sure how exact battery specs usually are; but you're talking about a 2.2% deviation from the spec...
     
  5. dextr3k macrumors 6502

    Joined:
    Nov 26, 2012
    #5
    I guess OP was just wondering how a battery can hold more than 100% charge, not how much more.

    But yeah, batteries aren't exact so it is possible to hold a bit more charge. That should be a good thing.
     
  6. dusk007 macrumors 68040

    dusk007

    Joined:
    Dec 5, 2009
    #6
    Overall batteries have a +/- 5 % capacity. Some ship with only 95% of designed cap. some with 105% and some exactly 100%.
    The battery program is never really doing anything wrong. All it does is read out the battery stats from sys rep. What is reported there may not be spot on but it usually is fairly right. Capacity can even change with temperature afaik. A warm battery holds more charge than a cold one. It also dies sooner ;)
     
  7. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #7
    It's not showing more than 100% charge. It's showing more than 100% health.
    It is perfectly normal if your battery health (maximum capacity) is more or less than 100%, even when brand new, or if it fluctuates up or down over time. The gradual decline is not in a straight line downward, and it may decline more rapidly at some times and slower at others. For further details, read the CHECKING STATUS AND HEALTH section of the following link.
    The link below should answer most, if not all, of your battery/charging questions. If you haven't already done so, I highly recommend you take the time to read it.
     

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